Add benchmark suite comparing sarin, wrk, and bombardier

perf: reduce memory allocations in request generator

.github/FUNDING.yml

@@ -1,2 +1 @@
 buy_me_a_coffee: aykhan
-custom: https://commerce.coinbase.com/checkout/0f33d2fb-54a6-44f5-8783-006ebf70d1a0

.github/workflows/lint.yaml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v5
       - uses: actions/setup-go@v6
         with:
-          go-version: 1.26.0
+          go-version: 1.26.1
       - name: go fix
         run: |
           go fix ./...
@@ -24,4 +24,4 @@ jobs:
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.9.0
+          version: v2.11.2

.github/workflows/release.yaml

@@ -35,7 +35,7 @@ jobs:
         run: |
           echo "VERSION=$(git describe --tags --always)" >> $GITHUB_ENV
           echo "GIT_COMMIT=$(git rev-parse HEAD)" >> $GITHUB_ENV
-          echo "GO_VERSION=1.26.0" >> $GITHUB_ENV
+          echo "GO_VERSION=1.26.1" >> $GITHUB_ENV
 
       - name: Set up Go
         if: github.event_name == 'release' || inputs.build_binaries

Dockerfile

@@ -1,4 +1,4 @@
-ARG GO_VERSION=1.26.0
+ARG GO_VERSION=1.26.1
 
 FROM docker.io/library/golang:${GO_VERSION}-alpine AS builder
 

Taskfile.yaml

@@ -3,7 +3,7 @@ version: "3"
 
 vars:
   BIN_DIR: ./bin
-  GOLANGCI_LINT_VERSION: v2.9.0
+  GOLANGCI_LINT_VERSION: v2.11.2
   GOLANGCI: "{{.BIN_DIR}}/golangci-lint-{{.GOLANGCI_LINT_VERSION}}"
 
 tasks:

benchmark/README.md

@@ -0,0 +1,42 @@
+# Benchmark
+
+Compares [sarin](https://github.com/aykhans/sarin), [wrk](https://github.com/wg/wrk), and [bombardier](https://github.com/codesenberg/bombardier) against a minimal C HTTP server using epoll.
+
+## Requirements
+
+- `sarin`, `wrk`, `bombardier` in PATH
+- `gcc`
+
+## Usage
+
+```bash
+./benchmark/run.sh
+```
+
+Configuration is at the top of `run.sh`:
+
+```bash
+DURATION="30s"
+CONNECTIONS=(50 100 200)
+ITERATIONS=3
+```
+
+## Structure
+
+```
+benchmark/
+  run.sh          - benchmark script
+  server/
+    server.c      - C epoll HTTP server (returns "ok")
+  results/        - output directory (auto-created)
+```
+
+## Output
+
+Each run produces per-tool files:
+
+- `*.out` - tool stdout (throughput, latency)
+- `*.time` - `/usr/bin/time -v` output (peak memory, CPU time)
+- `*_resources.csv` - sampled CPU/memory during run
+
+A summary table is printed at the end with requests/sec, total requests, elapsed time, and peak memory.

benchmark/run.sh

@@ -0,0 +1,335 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# ─── Configuration ───────────────────────────────────────────────────────────
+SERVER_PORT=8080
+SERVER_URL="http://127.0.0.1:${SERVER_PORT}/"
+DURATION="30s"
+CONNECTIONS=(50 100 200)
+ITERATIONS=3
+WARMUP_DURATION="5s"
+RESULTS_DIR="benchmark/results/$(date +%Y%m%d_%H%M%S)"
+
+# ─── Colors ──────────────────────────────────────────────────────────────────
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+CYAN='\033[0;36m'
+BOLD='\033[1m'
+NC='\033[0m'
+
+log()  { echo -e "${GREEN}[+]${NC} $*"; }
+warn() { echo -e "${YELLOW}[!]${NC} $*"; }
+err()  { echo -e "${RED}[✗]${NC} $*" >&2; }
+header() { echo -e "\n${BOLD}${CYAN}═══ $* ═══${NC}\n"; }
+
+# ─── Dependency checks ──────────────────────────────────────────────────────
+check_deps() {
+    local missing=()
+    for cmd in wrk bombardier sarin gcc; do
+        if ! command -v "$cmd" &>/dev/null; then
+            missing+=("$cmd")
+        fi
+    done
+    if [[ ${#missing[@]} -gt 0 ]]; then
+        err "Missing dependencies: ${missing[*]}"
+        echo "Install them before running this benchmark."
+        exit 1
+    fi
+    log "All dependencies found"
+}
+
+# ─── Build & manage the C server ────────────────────────────────────────────
+build_server() {
+    header "Building C HTTP server"
+    gcc -O3 -o benchmark/server/bench-server benchmark/server/server.c
+    log "Server built successfully"
+}
+
+start_server() {
+    log "Starting server on port ${SERVER_PORT}..."
+    benchmark/server/bench-server &
+    SERVER_PID=$!
+    sleep 1
+
+    if ! kill -0 "$SERVER_PID" 2>/dev/null; then
+        err "Server failed to start"
+        exit 1
+    fi
+    log "Server running (PID: ${SERVER_PID})"
+}
+
+stop_server() {
+    if [[ -n "${SERVER_PID:-}" ]] && kill -0 "$SERVER_PID" 2>/dev/null; then
+        kill "$SERVER_PID" 2>/dev/null || true
+        wait "$SERVER_PID" 2>/dev/null || true
+        log "Server stopped"
+    fi
+}
+
+trap stop_server EXIT
+
+# ─── Resource monitoring ────────────────────────────────────────────────────
+start_monitor() {
+    local tool_name=$1
+    local conns=$2
+    local iter=$3
+    local monitor_file="${RESULTS_DIR}/${tool_name}_c${conns}_i${iter}_resources.csv"
+
+    echo "timestamp,cpu%,mem_kb" > "$monitor_file"
+
+    (
+        while true; do
+            # Find the PID of the tool by name (exclude monitor itself)
+            local pid
+            pid=$(pgrep -x "$tool_name" 2>/dev/null | head -1) || true
+            if [[ -n "$pid" ]]; then
+                local stats
+                stats=$(ps -p "$pid" -o %cpu=,%mem=,rss= 2>/dev/null) || true
+                if [[ -n "$stats" ]]; then
+                    local cpu mem_kb
+                    cpu=$(echo "$stats" | awk '{print $1}')
+                    mem_kb=$(echo "$stats" | awk '{print $3}')
+                    echo "$(date +%s),$cpu,$mem_kb" >> "$monitor_file"
+                fi
+            fi
+            sleep 0.5
+        done
+    ) &
+    MONITOR_PID=$!
+}
+
+stop_monitor() {
+    if [[ -n "${MONITOR_PID:-}" ]] && kill -0 "$MONITOR_PID" 2>/dev/null; then
+        kill "$MONITOR_PID" 2>/dev/null || true
+        wait "$MONITOR_PID" 2>/dev/null || true
+    fi
+}
+
+# ─── Benchmark runners ─────────────────────────────────────────────────────
+run_wrk() {
+    local conns=$1
+    local dur=$2
+    local out_file=$3
+    local threads=$((conns < 10 ? conns : 10))
+
+    /usr/bin/time -v wrk -t"${threads}" -c"${conns}" -d"${dur}" "${SERVER_URL}" \
+        2>"${out_file}.time" | tee "${out_file}.out"
+}
+
+run_bombardier() {
+    local conns=$1
+    local dur=$2
+    local out_file=$3
+
+    /usr/bin/time -v bombardier -c "${conns}" -d "${dur}" --print result "${SERVER_URL}" \
+        2>"${out_file}.time" | tee "${out_file}.out"
+}
+
+run_sarin() {
+    local conns=$1
+    local dur=$2
+    local out_file=$3
+
+    /usr/bin/time -v sarin -U "${SERVER_URL}" -c "${conns}" -d "${dur}" -q \
+        2>"${out_file}.time" | tee "${out_file}.out"
+}
+
+# ─── Warmup ──────────────────────────────────────────────────────────────────
+warmup() {
+    header "Warming up server"
+    wrk -t4 -c50 -d"${WARMUP_DURATION}" "${SERVER_URL}" > /dev/null 2>&1
+    log "Warmup complete"
+    sleep 2
+}
+
+# ─── Extract peak memory from /usr/bin/time -v output ────────────────────────
+extract_peak_mem() {
+    local time_file=$1
+    grep "Maximum resident set size" "$time_file" 2>/dev/null | awk '{print $NF}' || echo "N/A"
+}
+
+# ─── Extract total requests from tool output ─────────────────────────────────
+extract_requests() {
+    local tool=$1
+    local out_file=$2
+
+    case "$tool" in
+        wrk)
+            # wrk: "312513 requests in 2.10s, ..."
+            grep "requests in" "$out_file" 2>/dev/null | awk '{print $1}' || echo "N/A"
+            ;;
+        bombardier)
+            # bombardier: "1xx - 0, 2xx - 100000, 3xx - 0, 4xx - 0, 5xx - 0"
+            # Sum all HTTP code counts
+            grep -E "^\s+1xx" "$out_file" 2>/dev/null | \
+                awk -F'[,-]' '{sum=0; for(i=1;i<=NF;i++){gsub(/[^0-9]/,"",$i); if($i+0>0) sum+=$i} print sum}' || echo "N/A"
+            ;;
+        sarin)
+            # sarin table: "│ Total │ 1556177 │ ..."
+            grep -i "total" "$out_file" 2>/dev/null | awk -F'│' '{gsub(/[[:space:]]/, "", $3); print $3}' || echo "N/A"
+            ;;
+    esac
+}
+
+extract_elapsed() {
+    local time_file=$1
+    grep "wall clock" "$time_file" 2>/dev/null | awk '{print $NF}' || echo "N/A"
+}
+
+extract_rps() {
+    local tool=$1
+    local out_file=$2
+
+    case "$tool" in
+        wrk)
+            # wrk: "Requests/sec:  12345.67"
+            grep "Requests/sec" "$out_file" 2>/dev/null | awk '{print $2}' || echo "N/A"
+            ;;
+        bombardier)
+            # bombardier: "Reqs/sec  12345.67  ..."
+            grep -i "reqs/sec" "$out_file" 2>/dev/null | awk '{print $2}' || echo "N/A"
+            ;;
+        sarin)
+            # sarin doesn't output rps - calculate from total requests and duration
+            local total
+            total=$(extract_requests "sarin" "$out_file")
+            if [[ "$total" != "N/A" && -n "$total" ]]; then
+                local dur_secs
+                dur_secs=$(echo "$DURATION" | sed 's/s$//')
+                awk "BEGIN {printf \"%.2f\", $total / $dur_secs}"
+            else
+                echo "N/A"
+            fi
+            ;;
+    esac
+}
+
+# ─── Print comparison table ──────────────────────────────────────────────────
+print_table() {
+    local title=$1
+    local extract_fn=$2
+    shift 2
+    local columns=("$@")
+
+    echo -e "${BOLD}${title}:${NC}"
+    printf "%-12s" ""
+    for col in "${columns[@]}"; do
+        printf "%-18s" "$col"
+    done
+    echo ""
+
+    local tools=("wrk" "bombardier" "sarin")
+    for tool in "${tools[@]}"; do
+        printf "%-12s" "$tool"
+        for col in "${columns[@]}"; do
+            local val
+            val=$($extract_fn "$tool" "$col")
+            printf "%-18s" "${val}"
+        done
+        echo ""
+    done
+    echo ""
+}
+
+# ─── Main ────────────────────────────────────────────────────────────────────
+main() {
+    header "HTTP Load Testing Tool Benchmark"
+    echo "Tools:       wrk, bombardier, sarin"
+    echo "Duration:    ${DURATION} per run"
+    echo "Connections: ${CONNECTIONS[*]}"
+    echo "Iterations:  ${ITERATIONS} per configuration"
+    echo ""
+
+    check_deps
+
+    mkdir -p "${RESULTS_DIR}"
+    log "Results will be saved to ${RESULTS_DIR}/"
+
+    build_server
+    start_server
+    warmup
+
+    local tools=("wrk" "bombardier" "sarin")
+
+    for conns in "${CONNECTIONS[@]}"; do
+        header "Testing with ${conns} connections"
+
+        for tool in "${tools[@]}"; do
+            echo -e "${BOLD}--- ${tool} (${conns} connections) ---${NC}"
+
+            for iter in $(seq 1 "$ITERATIONS"); do
+                local out_file="${RESULTS_DIR}/${tool}_c${conns}_i${iter}"
+                echo -n "  Run ${iter}/${ITERATIONS}... "
+
+                start_monitor "$tool" "$conns" "$iter"
+
+                case "$tool" in
+                    wrk)         run_wrk "$conns" "$DURATION" "$out_file" > /dev/null 2>&1 ;;
+                    bombardier)  run_bombardier "$conns" "$DURATION" "$out_file" > /dev/null 2>&1 ;;
+                    sarin)       run_sarin "$conns" "$DURATION" "$out_file" > /dev/null 2>&1 ;;
+                esac
+
+                stop_monitor
+
+                local peak_mem rps elapsed
+                peak_mem=$(extract_peak_mem "${out_file}.time")
+                rps=$(extract_rps "$tool" "${out_file}.out")
+                elapsed=$(extract_elapsed "${out_file}.time")
+                echo -e "done (elapsed: ${elapsed}, rps: ${rps}, peak mem: ${peak_mem} KB)"
+
+                sleep 2
+            done
+            echo ""
+        done
+    done
+
+    # ─── Summary ─────────────────────────────────────────────────────────
+    header "Summary"
+    echo "Raw results saved to: ${RESULTS_DIR}/"
+    echo ""
+    echo "Files per run:"
+    echo "  *.out       - tool stdout (throughput, latency stats)"
+    echo "  *.time      - /usr/bin/time output (peak memory, CPU time)"
+    echo "  *_resources.csv - sampled CPU/memory during run"
+    echo ""
+
+    local columns=()
+    for conns in "${CONNECTIONS[@]}"; do
+        columns+=("c=${conns}")
+    done
+
+    _get_rps() {
+        local c=${2#c=}
+        extract_rps "$1" "${RESULTS_DIR}/${1}_c${c}_i${ITERATIONS}.out"
+    }
+
+    _get_total() {
+        local c=${2#c=}
+        extract_requests "$1" "${RESULTS_DIR}/${1}_c${c}_i${ITERATIONS}.out"
+    }
+
+    _get_mem() {
+        local c=${2#c=}
+        extract_peak_mem "${RESULTS_DIR}/${1}_c${c}_i${ITERATIONS}.time"
+    }
+
+    _get_elapsed() {
+        local c=${2#c=}
+        extract_elapsed "${RESULTS_DIR}/${1}_c${c}_i${ITERATIONS}.time"
+    }
+
+    print_table "Requests/sec" _get_rps "${columns[@]}"
+    print_table "Total Requests" _get_total "${columns[@]}"
+    print_table "Elapsed Time" _get_elapsed "${columns[@]}"
+    print_table "Peak Memory (KB)" _get_mem "${columns[@]}"
+
+    log "Benchmark complete!"
+    echo ""
+    echo "To inspect individual results:"
+    echo "  cat ${RESULTS_DIR}/wrk_c200_i1.out"
+    echo "  cat ${RESULTS_DIR}/sarin_c200_i1.out"
+    echo "  cat ${RESULTS_DIR}/bombardier_c200_i1.out"
+}
+
+main "$@"

benchmark/server/server.c

@@ -0,0 +1,114 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#define PORT 8080
+#define MAX_EVENTS 1024
+#define BUF_SIZE 4096
+
+static const char RESPONSE[] =
+    "HTTP/1.1 200 OK\r\n"
+    "Content-Length: 2\r\n"
+    "Content-Type: text/plain\r\n"
+    "Connection: keep-alive\r\n"
+    "\r\n"
+    "ok";
+
+static const int RESPONSE_LEN = sizeof(RESPONSE) - 1;
+
+static void set_nonblocking(int fd) {
+    int flags = fcntl(fd, F_GETFL, 0);
+    fcntl(fd, F_SETFL, flags | O_NONBLOCK);
+}
+
+int main(void) {
+    signal(SIGPIPE, SIG_IGN);
+
+    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
+    if (server_fd < 0) {
+        perror("socket");
+        return 1;
+    }
+
+    int opt = 1;
+    setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    setsockopt(server_fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
+    setsockopt(server_fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
+
+    struct sockaddr_in addr = {
+        .sin_family = AF_INET,
+        .sin_port = htons(PORT),
+        .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
+    };
+
+    if (bind(server_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        perror("bind");
+        return 1;
+    }
+
+    if (listen(server_fd, SOMAXCONN) < 0) {
+        perror("listen");
+        return 1;
+    }
+
+    set_nonblocking(server_fd);
+
+    int epoll_fd = epoll_create1(0);
+    struct epoll_event ev = {.events = EPOLLIN, .data.fd = server_fd};
+    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, server_fd, &ev);
+
+    struct epoll_event events[MAX_EVENTS];
+    char buf[BUF_SIZE];
+
+    fprintf(stderr, "Listening on http://127.0.0.1:%d\n", PORT);
+
+    for (;;) {
+        int n = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
+        for (int i = 0; i < n; i++) {
+            if (events[i].data.fd == server_fd) {
+                /* Accept all pending connections */
+                for (;;) {
+                    int client_fd = accept(server_fd, NULL, NULL);
+                    if (client_fd < 0) {
+                        if (errno == EAGAIN || errno == EWOULDBLOCK)
+                            break;
+                        continue;
+                    }
+                    set_nonblocking(client_fd);
+                    int tcp_opt = 1;
+                    setsockopt(client_fd, IPPROTO_TCP, TCP_NODELAY, &tcp_opt, sizeof(tcp_opt));
+                    struct epoll_event cev = {.events = EPOLLIN | EPOLLET, .data.fd = client_fd};
+                    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client_fd, &cev);
+                }
+            } else {
+                int fd = events[i].data.fd;
+                /* Read all available data and respond to each request */
+                for (;;) {
+                    ssize_t nread = read(fd, buf, BUF_SIZE);
+                    if (nread <= 0) {
+                        if (nread == 0 || (errno != EAGAIN && errno != EWOULDBLOCK)) {
+                            close(fd);
+                        }
+                        break;
+                    }
+                    if (write(fd, RESPONSE, RESPONSE_LEN) < 0) {
+                        close(fd);
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    close(server_fd);
+    close(epoll_fd);
+    return 0;
+}

cmd/cli/main.go

@@ -14,7 +14,7 @@ import (
 )
 
 func main() {
-	ctx, cancel := context.WithCancel(context.Background())
+	ctx, cancel := context.WithCancel(context.Background()) //nolint:gosec // G118: cancel is called in listenForTermination goroutine
 	go listenForTermination(func() { cancel() })
 
 	combinedConfig := config.ReadAllConfigs()

docs/configuration.md

@@ -105,6 +105,12 @@ SARIN_CONFIG_FILE=/config1.yaml sarin -f /config2.yaml -f https://example.com/co
 
 If all four files define `url`, the value from `config3.yaml` wins.
 
+**Merge behavior by field:**
+
+- **Scalar fields** (`url`, `requests`, `duration`, `timeout`, `concurrency`, etc.) — higher priority overrides lower priority
+- **Method and Body** — higher priority overrides lower priority (no merging)
+- **Headers, Params, Cookies, Proxies, Values, Lua, and Js** — accumulated across all config files
+
 ## URL
 
 Target URL. Must be HTTP or HTTPS. The URL path supports [templating](templating.md), allowing dynamic path generation per request.

docs/examples.md

@@ -199,7 +199,7 @@ params:
 
 ```sh
 sarin -U http://example.com/users -r 1000 -c 10 \
-  -P "id={{ fakeit_IntRange 1 1000 }}" \
+  -P "id={{ fakeit_Number 1 1000 }}" \
   -P "fields=name,email"
 ```
 
@@ -211,7 +211,7 @@ url: http://example.com/users
 requests: 1000
 concurrency: 10
 params:
-    id: "{{ fakeit_IntRange 1 1000 }}"
+    id: "{{ fakeit_Number 1 1000 }}"
     fields: "name,email"
 ```
 

docs/templating.md

@@ -10,6 +10,8 @@ Sarin supports Go templates in URL paths, methods, bodies, headers, params, cook
 - [General Functions](#general-functions)
     - [String Functions](#string-functions)
     - [Collection Functions](#collection-functions)
+    - [Time Functions](#time-functions)
+    - [Crypto Functions](#crypto-functions)
     - [Body Functions](#body-functions)
     - [File Functions](#file-functions)
 - [Fake Data Functions](#fake-data-functions)
@@ -109,6 +111,24 @@ sarin -U http://example.com/users \
 | `slice_Int(values ...int)`               | Create int slice                              | `{{ slice_Int 1 2 3 }}`                                  |
 | `slice_Uint(values ...uint)`             | Create uint slice                             | `{{ slice_Uint 1 2 3 }}`                                 |
 
+### Time Functions
+
+| Function                 | Description                                 | Example                                                                         |
+| ------------------------ | ------------------------------------------- | ------------------------------------------------------------------------------- |
+| `time_NowUnix`           | Current Unix timestamp (seconds)            | `{{ time_NowUnix }}` → `1735689600`                                             |
+| `time_NowUnixMilli`      | Current Unix timestamp (milliseconds)       | `{{ time_NowUnixMilli }}` → `1735689600123`                                     |
+| `time_NowRFC3339`        | Current time in RFC3339 format              | `{{ time_NowRFC3339 }}` → `"2026-02-26T21:00:00Z"`                              |
+| `time_Format(layout, t)` | Format a `time.Time` value with a Go layout | `{{ time_Format "2006-01-02" (strings_ToDate "2024-05-10") }}` → `"2024-05-10"` |
+
+### Crypto Functions
+
+| Function                             | Description                                | Example                                      |
+| ------------------------------------ | ------------------------------------------ | -------------------------------------------- |
+| `crypto_SHA256(s string)`            | SHA-256 hash (hex-encoded)                 | `{{ crypto_SHA256 "hello" }}`                |
+| `crypto_MD5(s string)`               | MD5 hash (hex-encoded)                     | `{{ crypto_MD5 "hello" }}`                   |
+| `crypto_HMACSHA256(key, msg string)` | HMAC-SHA256 signature (hex-encoded)        | `{{ crypto_HMACSHA256 "secret" "payload" }}` |
+| `crypto_Base64URL(s string)`         | Base64 URL-safe encoding (without padding) | `{{ crypto_Base64URL "hello world" }}`       |
+
 ### Body Functions
 
 | Function                         | Description                                                                                                                                                                                                 | Example                                                             |
@@ -153,11 +173,18 @@ body: '{{ body_FormData "twitter" "@@username" }}'
 
 | Function                     | Description                                                                                               | Example                                 |
 | ---------------------------- | --------------------------------------------------------------------------------------------------------- | --------------------------------------- |
+| `file_Read(source string)`   | Read a file (local path or URL) and return raw content as string. Files are cached after first read.      | `{{ file_Read "/path/to/file.txt" }}`   |
 | `file_Base64(source string)` | Read a file (local path or URL) and return its Base64 encoded content. Files are cached after first read. | `{{ file_Base64 "/path/to/file.pdf" }}` |
 
-**`file_Base64` Details:**
+**`file_Read` and `file_Base64` Details:**
 
 ```yaml
+# Local file as plain text
+body: '{{ file_Read "/path/to/template.json" }}'
+
+# Remote text file
+body: '{{ file_Read "https://example.com/payload.txt" }}'
+
 # Local file as Base64 in JSON body
 body: '{"file": "{{ file_Base64 "/path/to/document.pdf" }}", "filename": "document.pdf"}'
 
@@ -239,24 +266,24 @@ These functions are powered by [gofakeit](https://github.com/brianvoe/gofakeit)
 
 ### Address
 
-| Function                                            | Description                  | Example Output                                      |
-| --------------------------------------------------- | ---------------------------- | --------------------------------------------------- |
-| `fakeit_City`                                       | City name                    | `"Marcelside"`                                      |
-| `fakeit_Country`                                    | Country name                 | `"United States of America"`                        |
-| `fakeit_CountryAbr`                                 | Country abbreviation         | `"US"`                                              |
-| `fakeit_State`                                      | State name                   | `"Illinois"`                                        |
-| `fakeit_StateAbr`                                   | State abbreviation           | `"IL"`                                              |
-| `fakeit_Street`                                     | Full street                  | `"364 East Rapidsborough"`                          |
-| `fakeit_StreetName`                                 | Street name                  | `"View"`                                            |
-| `fakeit_StreetNumber`                               | Street number                | `"13645"`                                           |
-| `fakeit_StreetPrefix`                               | Street prefix                | `"East"`                                            |
-| `fakeit_StreetSuffix`                               | Street suffix                | `"Ave"`                                             |
-| `fakeit_Unit`                                       | Unit                         | `"Apt 123"`                                         |
-| `fakeit_Zip`                                        | ZIP code                     | `"13645"`                                           |
-| `fakeit_Latitude`                                   | Random latitude              | `-73.534056`                                        |
-| `fakeit_Longitude`                                  | Random longitude             | `-147.068112`                                       |
-| `fakeit_LatitudeInRange(min float64, max float64)`  | Latitude in specified range  | `{{ fakeit_LatitudeInRange 0 90 }}` → `22.921026`   |
-| `fakeit_LongitudeInRange(min float64, max float64)` | Longitude in specified range | `{{ fakeit_LongitudeInRange 0 180 }}` → `-8.170450` |
+| Function                                            | Description                  | Example Output                                       |
+| --------------------------------------------------- | ---------------------------- | ---------------------------------------------------- |
+| `fakeit_City`                                       | City name                    | `"Marcelside"`                                       |
+| `fakeit_Country`                                    | Country name                 | `"United States of America"`                         |
+| `fakeit_CountryAbr`                                 | Country abbreviation         | `"US"`                                               |
+| `fakeit_State`                                      | State name                   | `"Illinois"`                                         |
+| `fakeit_StateAbr`                                   | State abbreviation           | `"IL"`                                               |
+| `fakeit_Street`                                     | Full street                  | `"364 East Rapidsborough"`                           |
+| `fakeit_StreetName`                                 | Street name                  | `"View"`                                             |
+| `fakeit_StreetNumber`                               | Street number                | `"13645"`                                            |
+| `fakeit_StreetPrefix`                               | Street prefix                | `"East"`                                             |
+| `fakeit_StreetSuffix`                               | Street suffix                | `"Ave"`                                              |
+| `fakeit_Unit`                                       | Unit                         | `"Apt 123"`                                          |
+| `fakeit_Zip`                                        | ZIP code                     | `"13645"`                                            |
+| `fakeit_Latitude`                                   | Random latitude              | `-73.534056`                                         |
+| `fakeit_Longitude`                                  | Random longitude             | `-147.068112`                                        |
+| `fakeit_LatitudeInRange(min float64, max float64)`  | Latitude in specified range  | `{{ fakeit_LatitudeInRange 0 90 }}` → `22.921026`    |
+| `fakeit_LongitudeInRange(min float64, max float64)` | Longitude in specified range | `{{ fakeit_LongitudeInRange 0 180 }}` → `122.471830` |
 
 ### Game
 
@@ -343,16 +370,16 @@ These functions are powered by [gofakeit](https://github.com/brianvoe/gofakeit)
 
 ### Text
 
-| Function                                                                                 | Description                                     | Example                                       |
-| ---------------------------------------------------------------------------------------- | ----------------------------------------------- | --------------------------------------------- |
-| `fakeit_Sentence`                                                                        | Random sentence                                 | `{{ fakeit_Sentence }}`                       |
-| `fakeit_Paragraph`                                                                       | Random paragraph                                | `{{ fakeit_Paragraph }}`                      |
-| `fakeit_LoremIpsumWord`                                                                  | Lorem ipsum word                                | `"lorem"`                                     |
-| `fakeit_LoremIpsumSentence(wordCount int)`                                               | Lorem ipsum sentence with specified word count  | `{{ fakeit_LoremIpsumSentence 5 }}`           |
-| `fakeit_LoremIpsumParagraph(paragraphs int, sentences int, words int, separator string)` | Lorem ipsum paragraphs with specified structure | `{{ fakeit_LoremIpsumParagraph 1 3 5 "\n" }}` |
-| `fakeit_Question`                                                                        | Random question                                 | `"What is your name?"`                        |
-| `fakeit_Quote`                                                                           | Random quote                                    | `"Life is what happens..."`                   |
-| `fakeit_Phrase`                                                                          | Random phrase                                   | `"a piece of cake"`                           |
+| Function                                                                                 | Description                                     | Example                                               |
+| ---------------------------------------------------------------------------------------- | ----------------------------------------------- | ----------------------------------------------------- |
+| `fakeit_Sentence(wordCount ...int)`                                                      | Random sentence (optional word count)           | `{{ fakeit_Sentence }}` or `{{ fakeit_Sentence 10 }}` |
+| `fakeit_Paragraph`                                                                       | Random paragraph                                | `{{ fakeit_Paragraph }}`                              |
+| `fakeit_LoremIpsumWord`                                                                  | Lorem ipsum word                                | `"lorem"`                                             |
+| `fakeit_LoremIpsumSentence(wordCount int)`                                               | Lorem ipsum sentence with specified word count  | `{{ fakeit_LoremIpsumSentence 5 }}`                   |
+| `fakeit_LoremIpsumParagraph(paragraphs int, sentences int, words int, separator string)` | Lorem ipsum paragraphs with specified structure | `{{ fakeit_LoremIpsumParagraph 1 3 5 "\n" }}`         |
+| `fakeit_Question`                                                                        | Random question                                 | `"What is your name?"`                                |
+| `fakeit_Quote`                                                                           | Random quote                                    | `"Life is what happens..."`                           |
+| `fakeit_Phrase`                                                                          | Random phrase                                   | `"a piece of cake"`                                   |
 
 ### Foods
 

go.mod

@@ -1,9 +1,9 @@
 module go.aykhans.me/sarin
 
-go 1.26.0
+go 1.26.1
 
 require (
-	github.com/brianvoe/gofakeit/v7 v7.14.0
+	github.com/brianvoe/gofakeit/v7 v7.14.1
 	github.com/charmbracelet/bubbles v1.0.0
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/glamour v0.10.0
@@ -15,7 +15,7 @@ require (
 	github.com/yuin/gopher-lua v1.1.1
 	go.aykhans.me/utils v1.0.7
 	go.yaml.in/yaml/v4 v4.0.0-rc.3
-	golang.org/x/net v0.50.0
+	golang.org/x/net v0.52.0
 )
 
 require (
@@ -53,7 +53,7 @@ require (
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	github.com/yuin/goldmark v1.7.16 // indirect
 	github.com/yuin/goldmark-emoji v1.0.6 // indirect
-	golang.org/x/sys v0.41.0 // indirect
-	golang.org/x/term v0.40.0 // indirect
-	golang.org/x/text v0.34.0 // indirect
+	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/term v0.41.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
 )

go.sum

@@ -14,8 +14,8 @@ github.com/aymanbagabas/go-udiff v0.3.1 h1:LV+qyBQ2pqe0u42ZsUEtPiCaUoqgA9gYRDs3v
 github.com/aymanbagabas/go-udiff v0.3.1/go.mod h1:G0fsKmG+P6ylD0r6N/KgQD/nWzgfnl8ZBcNLgcbrw8E=
 github.com/aymerick/douceur v0.2.0 h1:Mv+mAeH1Q+n9Fr+oyamOlAkUNPWPlA8PPGR0QAaYuPk=
 github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd30/FjWUq4=
-github.com/brianvoe/gofakeit/v7 v7.14.0 h1:R8tmT/rTDJmD2ngpqBL9rAKydiL7Qr2u3CXPqRt59pk=
-github.com/brianvoe/gofakeit/v7 v7.14.0/go.mod h1:QXuPeBw164PJCzCUZVmgpgHJ3Llj49jSLVkKPMtxtxA=
+github.com/brianvoe/gofakeit/v7 v7.14.1 h1:a7fe3fonbj0cW3wgl5VwIKfZtiH9C3cLnwcIXWT7sow=
+github.com/brianvoe/gofakeit/v7 v7.14.1/go.mod h1:QXuPeBw164PJCzCUZVmgpgHJ3Llj49jSLVkKPMtxtxA=
 github.com/charmbracelet/bubbles v1.0.0 h1:12J8/ak/uCZEMQ6KU7pcfwceyjLlWsDLAxB5fXonfvc=
 github.com/charmbracelet/bubbles v1.0.0/go.mod h1:9d/Zd5GdnauMI5ivUIVisuEm3ave1XwXtD1ckyV6r3E=
 github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
@@ -111,16 +111,16 @@ go.yaml.in/yaml/v4 v4.0.0-rc.3 h1:3h1fjsh1CTAPjW7q/EMe+C8shx5d8ctzZTrLcs/j8Go=
 go.yaml.in/yaml/v4 v4.0.0-rc.3/go.mod h1:aZqd9kCMsGL7AuUv/m/PvWLdg5sjJsZ4oHDEnfPPfY0=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
-golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
-golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
+golang.org/x/net v0.52.0 h1:He/TN1l0e4mmR3QqHMT2Xab3Aj3L9qjbhRm78/6jrW0=
+golang.org/x/net v0.52.0/go.mod h1:R1MAz7uMZxVMualyPXb+VaqGSa3LIaUqk0eEt3w36Sw=
 golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
-golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/term v0.40.0 h1:36e4zGLqU4yhjlmxEaagx2KuYbJq3EwY8K943ZsHcvg=
-golang.org/x/term v0.40.0/go.mod h1:w2P8uVp06p2iyKKuvXIm7N/y0UCRt3UfJTfZ7oOpglM=
-golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
-golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
+golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
+golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
+golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
+golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
+golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

internal/config/config.go

@@ -275,7 +275,7 @@ func (config Config) Print() bool {
 func (config *Config) Merge(newConfig *Config) {
 	config.Files = append(config.Files, newConfig.Files...)
 	if len(newConfig.Methods) > 0 {
-		config.Methods = append(config.Methods, newConfig.Methods...)
+		config.Methods = newConfig.Methods
 	}
 	if newConfig.URL != nil {
 		config.URL = newConfig.URL
@@ -317,7 +317,7 @@ func (config *Config) Merge(newConfig *Config) {
 		config.Cookies = append(config.Cookies, newConfig.Cookies...)
 	}
 	if len(newConfig.Bodies) != 0 {
-		config.Bodies = append(config.Bodies, newConfig.Bodies...)
+		config.Bodies = newConfig.Bodies
 	}
 	if len(newConfig.Proxies) != 0 {
 		config.Proxies.Append(newConfig.Proxies...)
@@ -418,7 +418,7 @@ func (config Config) Validate() error {
 		validationErrors = append(validationErrors, types.NewFieldValidationError("Duration", "0", errors.New("duration must be greater than 0")))
 	}
 
-	if *config.Timeout < 1 {
+	if config.Timeout == nil || *config.Timeout < 1 {
 		validationErrors = append(validationErrors, types.NewFieldValidationError("Timeout", "0", errors.New("timeout must be greater than 0")))
 	}
 

internal/config/env.go

@@ -157,7 +157,7 @@ func (parser ConfigENVParser) Parse() (*Config, error) {
 				types.NewFieldParseError(
 					parser.getFullEnvName("DURATION"),
 					duration,
-					errors.New("invalid value duration, expected a duration string (e.g., '10s', '1h30m')"),
+					errors.New("invalid value for duration, expected a duration string (e.g., '10s', '1h30m')"),
 				),
 			)
 		} else {
@@ -173,7 +173,7 @@ func (parser ConfigENVParser) Parse() (*Config, error) {
 				types.NewFieldParseError(
 					parser.getFullEnvName("TIMEOUT"),
 					timeout,
-					errors.New("invalid value duration, expected a duration string (e.g., '10s', '1h30m')"),
+					errors.New("invalid value for duration, expected a duration string (e.g., '10s', '1h30m')"),
 				),
 			)
 		} else {

internal/sarin/client.go

@@ -172,7 +172,6 @@ func fasthttpSocksDialerDualStackTimeout(ctx context.Context, proxyURL *url.URL,
 				return nil, types.NewProxyDialError(proxyStr, err)
 			}
 
-			// Cap DNS resolution to half the timeout to reserve time for dial
 			dnsCtx, dnsCancel := context.WithTimeout(ctx, timeout)
 			ips, err := net.DefaultResolver.LookupIP(dnsCtx, "ip", host)
 			dnsCancel()
@@ -244,7 +243,7 @@ func fasthttpHTTPSDialerDualStackTimeout(proxyURL *url.URL, timeout time.Duratio
 		}
 
 		// Upgrade to TLS
-		tlsConn := tls.Client(conn, &tls.Config{ //nolint:gosec
+		tlsConn := tls.Client(conn, &tls.Config{
 			ServerName: proxyURL.Hostname(),
 		})
 		if err := tlsConn.Handshake(); err != nil {

internal/sarin/helpers.go

@@ -8,7 +8,7 @@ import (
 func NewDefaultRandSource() rand.Source {
 	now := time.Now().UnixNano()
 	return rand.NewPCG(
-		uint64(now),     //nolint:gosec // G115: Safe conversion; UnixNano timestamp used as random seed, bit pattern is intentional
-		uint64(now>>32), //nolint:gosec // G115: Safe conversion; right-shifted timestamp for seed entropy, overflow is acceptable
+		uint64(now),
+		uint64(now>>32),
 	)
 }

internal/sarin/request.go

@@ -43,19 +43,34 @@ func NewRequestGenerator(
 	randSource := NewDefaultRandSource()
 	//nolint:gosec // G404: Using non-cryptographic rand for load testing, not security
 	localRand := rand.New(randSource)
-	templateFuncMap := NewDefaultTemplateFuncMap(randSource, fileCache)
 
-	pathGenerator, isPathGeneratorDynamic := createTemplateFunc(requestURL.Path, templateFuncMap)
-	methodGenerator, isMethodGeneratorDynamic := NewMethodGeneratorFunc(localRand, methods, templateFuncMap)
-	paramsGenerator, isParamsGeneratorDynamic := NewParamsGeneratorFunc(localRand, params, templateFuncMap)
-	headersGenerator, isHeadersGeneratorDynamic := NewHeadersGeneratorFunc(localRand, headers, templateFuncMap)
-	cookiesGenerator, isCookiesGeneratorDynamic := NewCookiesGeneratorFunc(localRand, cookies, templateFuncMap)
+	// Funcs() is only called if a value actually contains template syntax.
+	// The root template is shared across all createTemplateFunc calls so Funcs() is called at most once.
+	var templateRoot *template.Template
+	lazyTemplateRoot := func() *template.Template {
+		if templateRoot == nil {
+			templateRoot = template.New("").Funcs(NewDefaultTemplateFuncMap(randSource, fileCache))
+		}
+		return templateRoot
+	}
+
+	pathGenerator, isPathGeneratorDynamic := createTemplateFunc(requestURL.Path, lazyTemplateRoot)
+	methodGenerator, isMethodGeneratorDynamic := NewMethodGeneratorFunc(localRand, methods, lazyTemplateRoot)
+	paramsGenerator, isParamsGeneratorDynamic := NewParamsGeneratorFunc(localRand, params, lazyTemplateRoot)
+	headersGenerator, isHeadersGeneratorDynamic := NewHeadersGeneratorFunc(localRand, headers, lazyTemplateRoot)
+	cookiesGenerator, isCookiesGeneratorDynamic := NewCookiesGeneratorFunc(localRand, cookies, lazyTemplateRoot)
 
 	bodyTemplateFuncMapData := &BodyTemplateFuncMapData{}
-	bodyTemplateFuncMap := NewDefaultBodyTemplateFuncMap(randSource, bodyTemplateFuncMapData, fileCache)
-	bodyGenerator, isBodyGeneratorDynamic := NewBodyGeneratorFunc(localRand, bodies, bodyTemplateFuncMap)
+	var bodyTemplateRoot *template.Template
+	lazyBodyTemplateRoot := func() *template.Template {
+		if bodyTemplateRoot == nil {
+			bodyTemplateRoot = template.New("").Funcs(NewDefaultBodyTemplateFuncMap(randSource, bodyTemplateFuncMapData, fileCache))
+		}
+		return bodyTemplateRoot
+	}
+	bodyGenerator, isBodyGeneratorDynamic := NewBodyGeneratorFunc(localRand, bodies, lazyBodyTemplateRoot)
 
-	valuesGenerator := NewValuesGeneratorFunc(values, templateFuncMap)
+	valuesGenerator := NewValuesGeneratorFunc(values, lazyTemplateRoot)
 
 	hasScripts := scriptTransformer != nil && !scriptTransformer.IsEmpty()
 
@@ -91,7 +106,7 @@ func NewRequestGenerator(
 				return err
 			}
 
-			bodyTemplateFuncMapData.ClearFormDataContenType()
+			bodyTemplateFuncMapData.ClearFormDataContentType()
 			if err = bodyGenerator(reqData, data); err != nil {
 				return err
 			}
@@ -99,8 +114,8 @@ func NewRequestGenerator(
 			if err = headersGenerator(reqData, data); err != nil {
 				return err
 			}
-			if bodyTemplateFuncMapData.GetFormDataContenType() != "" {
-				reqData.Headers["Content-Type"] = append(reqData.Headers["Content-Type"], bodyTemplateFuncMapData.GetFormDataContenType())
+			if bodyTemplateFuncMapData.GetFormDataContentType() != "" {
+				reqData.Headers["Content-Type"] = append(reqData.Headers["Content-Type"], bodyTemplateFuncMapData.GetFormDataContentType())
 			}
 
 			if err = paramsGenerator(reqData, data); err != nil {
@@ -170,8 +185,8 @@ func applyRequestDataToFastHTTP(reqData *script.RequestData, req *fasthttp.Reque
 	}
 }
 
-func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
-	methodGenerator, isDynamic := buildStringSliceGenerator(localRand, methods, templateFunctions)
+func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, lazyRoot func() *template.Template) (requestDataGenerator, bool) {
+	methodGenerator, isDynamic := buildStringSliceGenerator(localRand, methods, lazyRoot)
 
 	var (
 		method string
@@ -188,8 +203,8 @@ func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, templateFunc
 	}, isDynamic
 }
 
-func NewBodyGeneratorFunc(localRand *rand.Rand, bodies []string, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
-	bodyGenerator, isDynamic := buildStringSliceGenerator(localRand, bodies, templateFunctions)
+func NewBodyGeneratorFunc(localRand *rand.Rand, bodies []string, lazyRoot func() *template.Template) (requestDataGenerator, bool) {
+	bodyGenerator, isDynamic := buildStringSliceGenerator(localRand, bodies, lazyRoot)
 
 	var (
 		body string
@@ -206,8 +221,8 @@ func NewBodyGeneratorFunc(localRand *rand.Rand, bodies []string, templateFunctio
 	}, isDynamic
 }
 
-func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
-	generators, isDynamic := buildKeyValueGenerators(localRand, params, templateFunctions)
+func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, lazyRoot func() *template.Template) (requestDataGenerator, bool) {
+	generators, isDynamic := buildKeyValueGenerators(localRand, params, lazyRoot)
 
 	var (
 		key, value string
@@ -231,8 +246,8 @@ func NewParamsGeneratorFunc(localRand *rand.Rand, params types.Params, templateF
 	}, isDynamic
 }
 
-func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
-	generators, isDynamic := buildKeyValueGenerators(localRand, headers, templateFunctions)
+func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, lazyRoot func() *template.Template) (requestDataGenerator, bool) {
+	generators, isDynamic := buildKeyValueGenerators(localRand, headers, lazyRoot)
 
 	var (
 		key, value string
@@ -256,8 +271,8 @@ func NewHeadersGeneratorFunc(localRand *rand.Rand, headers types.Headers, templa
 	}, isDynamic
 }
 
-func NewCookiesGeneratorFunc(localRand *rand.Rand, cookies types.Cookies, templateFunctions template.FuncMap) (requestDataGenerator, bool) {
-	generators, isDynamic := buildKeyValueGenerators(localRand, cookies, templateFunctions)
+func NewCookiesGeneratorFunc(localRand *rand.Rand, cookies types.Cookies, lazyRoot func() *template.Template) (requestDataGenerator, bool) {
+	generators, isDynamic := buildKeyValueGenerators(localRand, cookies, lazyRoot)
 
 	var (
 		key, value string
@@ -281,11 +296,11 @@ func NewCookiesGeneratorFunc(localRand *rand.Rand, cookies types.Cookies, templa
 	}, isDynamic
 }
 
-func NewValuesGeneratorFunc(values []string, templateFunctions template.FuncMap) func() (valuesData, error) {
+func NewValuesGeneratorFunc(values []string, lazyRoot func() *template.Template) func() (valuesData, error) {
 	generators := make([]func(_ any) (string, error), len(values))
 
 	for i, v := range values {
-		generators[i], _ = createTemplateFunc(v, templateFunctions)
+		generators[i], _ = createTemplateFunc(v, lazyRoot)
 	}
 
 	var (
@@ -313,8 +328,12 @@ func NewValuesGeneratorFunc(values []string, templateFunctions template.FuncMap)
 	}
 }
 
-func createTemplateFunc(value string, templateFunctions template.FuncMap) (func(data any) (string, error), bool) {
-	tmpl, err := template.New("").Funcs(templateFunctions).Parse(value)
+func createTemplateFunc(value string, lazyRoot func() *template.Template) (func(data any) (string, error), bool) {
+	if !strings.Contains(value, "{{") {
+		return func(_ any) (string, error) { return value, nil }, false
+	}
+
+	tmpl, err := lazyRoot().New("").Parse(value)
 	if err == nil && hasTemplateActions(tmpl) {
 		var err error
 		return func(data any) (string, error) {
@@ -340,7 +359,7 @@ type keyValueItem interface {
 func buildKeyValueGenerators[T keyValueItem](
 	localRand *rand.Rand,
 	items []T,
-	templateFunctions template.FuncMap,
+	lazyRoot func() *template.Template,
 ) ([]keyValueGenerator, bool) {
 	isDynamic := false
 	generators := make([]keyValueGenerator, len(items))
@@ -350,7 +369,7 @@ func buildKeyValueGenerators[T keyValueItem](
 		keyValue := types.KeyValue[string, []string](item)
 
 		// Generate key function
-		keyFunc, keyIsDynamic := createTemplateFunc(keyValue.Key, templateFunctions)
+		keyFunc, keyIsDynamic := createTemplateFunc(keyValue.Key, lazyRoot)
 		if keyIsDynamic {
 			isDynamic = true
 		}
@@ -358,7 +377,7 @@ func buildKeyValueGenerators[T keyValueItem](
 		// Generate value functions
 		valueFuncs := make([]func(data any) (string, error), len(keyValue.Value))
 		for j, v := range keyValue.Value {
-			valueFunc, valueIsDynamic := createTemplateFunc(v, templateFunctions)
+			valueFunc, valueIsDynamic := createTemplateFunc(v, lazyRoot)
 			if valueIsDynamic {
 				isDynamic = true
 			}
@@ -381,7 +400,7 @@ func buildKeyValueGenerators[T keyValueItem](
 func buildStringSliceGenerator(
 	localRand *rand.Rand,
 	values []string,
-	templateFunctions template.FuncMap,
+	lazyRoot func() *template.Template,
 ) (func() func(data any) (string, error), bool) {
 	// Return a function that returns an empty string generator if values is empty
 	if len(values) == 0 {
@@ -393,7 +412,7 @@ func buildStringSliceGenerator(
 	valueFuncs := make([]func(data any) (string, error), len(values))
 
 	for i, value := range values {
-		valueFunc, valueIsDynamic := createTemplateFunc(value, templateFunctions)
+		valueFunc, valueIsDynamic := createTemplateFunc(value, lazyRoot)
 		if valueIsDynamic {
 			isDynamic = true
 		}

internal/sarin/sarin.go

@@ -484,13 +484,11 @@ func newHostClients(
 		proxiesRaw[i] = url.URL(proxy)
 	}
 
-	maxConns := max(fasthttp.DefaultMaxConnsPerHost, workers)
-	maxConns = ((maxConns * 50 / 100) + maxConns)
 	return NewHostClients(
 		ctx,
 		timeout,
 		proxiesRaw,
-		maxConns,
+		workers,
 		requestURL,
 		skipCertVerify,
 	)

internal/sarin/template.go

@@ -2,7 +2,11 @@ package sarin
 
 import (
 	"bytes"
+	"crypto/hmac"
+	"crypto/md5" // #nosec G501 -- exposed intentionally as a template utility helper
+	"crypto/sha256"
 	"encoding/base64"
+	"encoding/hex"
 	"math/rand/v2"
 	"mime/multipart"
 	"strings"
@@ -81,7 +85,47 @@ func NewDefaultTemplateFuncMap(randSource rand.Source, fileCache *FileCache) tem
 		"slice_Uint": func(values ...uint) []uint { return values },
 		"slice_Join": strings.Join,
 
+		// Time
+		"time_NowUnix":      func() int64 { return time.Now().Unix() },
+		"time_NowUnixMilli": func() int64 { return time.Now().UnixMilli() },
+		"time_NowRFC3339":   func() string { return time.Now().Format(time.RFC3339) },
+		"time_Format": func(layout string, t time.Time) string {
+			return t.Format(layout)
+		},
+
+		// Crypto
+		"crypto_SHA256": func(s string) string {
+			sum := sha256.Sum256([]byte(s))
+			return hex.EncodeToString(sum[:])
+		},
+		"crypto_MD5": func(s string) string {
+			sum := md5.Sum([]byte(s)) // #nosec G401 -- MD5 is intentionally provided as a non-security template helper
+			return hex.EncodeToString(sum[:])
+		},
+		"crypto_HMACSHA256": func(key string, msg string) string {
+			mac := hmac.New(sha256.New, []byte(key))
+			_, _ = mac.Write([]byte(msg))
+			return hex.EncodeToString(mac.Sum(nil))
+		},
+		"crypto_Base64URL": func(s string) string {
+			return base64.RawURLEncoding.EncodeToString([]byte(s))
+		},
+
 		// File
+		// file_Read reads a file (local or remote URL) and returns its content as a string.
+		// Usage: {{ file_Read "/path/to/file.txt" }}
+		//        {{ file_Read "https://example.com/data.txt" }}
+		"file_Read": func(source string) (string, error) {
+			if fileCache == nil {
+				return "", types.ErrFileCacheNotInitialized
+			}
+			cached, err := fileCache.GetOrLoad(source)
+			if err != nil {
+				return "", err
+			}
+			return string(cached.Content), nil
+		},
+
 		// file_Base64 reads a file (local or remote URL) and returns its Base64 encoded content.
 		// Usage: {{ file_Base64 "/path/to/file.pdf" }}
 		//        {{ file_Base64 "https://example.com/image.png" }}
@@ -242,7 +286,7 @@ func NewDefaultTemplateFuncMap(randSource rand.Source, fileCache *FileCache) tem
 		"fakeit_AdverbFrequencyDefinite":   fakeit.AdverbFrequencyDefinite,
 		"fakeit_AdverbFrequencyIndefinite": fakeit.AdverbFrequencyIndefinite,
 
-		// Propositions
+		// Prepositions
 		"fakeit_Preposition":         fakeit.Preposition,
 		"fakeit_PrepositionSimple":   fakeit.PrepositionSimple,
 		"fakeit_PrepositionDouble":   fakeit.PrepositionDouble,
@@ -545,15 +589,15 @@ func NewDefaultTemplateFuncMap(randSource rand.Source, fileCache *FileCache) tem
 }
 
 type BodyTemplateFuncMapData struct {
-	formDataContenType string
+	formDataContentType string
 }
 
-func (data BodyTemplateFuncMapData) GetFormDataContenType() string {
-	return data.formDataContenType
+func (data BodyTemplateFuncMapData) GetFormDataContentType() string {
+	return data.formDataContentType
 }
 
-func (data *BodyTemplateFuncMapData) ClearFormDataContenType() {
-	data.formDataContenType = ""
+func (data *BodyTemplateFuncMapData) ClearFormDataContentType() {
+	data.formDataContentType = ""
 }
 
 func NewDefaultBodyTemplateFuncMap(
@@ -584,7 +628,7 @@ func NewDefaultBodyTemplateFuncMap(
 
 			var multipartData bytes.Buffer
 			writer := multipart.NewWriter(&multipartData)
-			data.formDataContenType = writer.FormDataContentType()
+			data.formDataContentType = writer.FormDataContentType()
 
 			for i := 0; i < len(pairs); i += 2 {
 				key := pairs[i]