From 10287f9a80c1831ab5fbbb4782a8cd675ab9876c Mon Sep 17 00:00:00 2001
From: Tom Proctor <tomhjp@users.noreply.github.com>
Date: Wed, 15 Oct 2025 13:31:45 +0100
Subject: [PATCH] scripts: add benchmark.sh script for testing

This is the script I've been using locally to reproducibly simulate what
kind of speed-ups I can expect to see for a specific go project
depending on how close gocached is and how many cache hits we get. I
also experimented with a -miss-percentage flag on go-cacher, but the
results were roughly what you'd expect interpolating between cold and
warm benchmarks.

Typical output for running with defaults:

```shell-session
$ ./scripts/benchmark.sh
---- LATENCY=0 ----

Testing with cold cache...
2025/10/16 12:53:36 go-cacher: verbose mode enabled
2025/10/16 12:53:45 cacher: closing; 494 gets (0 hits, 494 misses, 0 errors); 1026 puts (0 errors)
Cold run took 8762ms

Testing with warm HTTP and disk cache...
2025/10/16 12:53:46 go-cacher: verbose mode enabled
2025/10/16 12:53:46 cacher: closing; 747 gets (744 hits, 3 misses, 0 errors); 3 puts (0 errors)
Warm run took 497ms

Testing with warm HTTP cache only...
2025/10/16 12:53:47 go-cacher: verbose mode enabled
2025/10/16 12:53:48 cacher: closing; 747 gets (744 hits, 3 misses, 0 errors); 3 puts (0 errors)
HTTP run took 628ms
```

Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>
---
 scripts/benchmark.sh | 96 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100755 scripts/benchmark.sh

diff --git a/scripts/benchmark.sh b/scripts/benchmark.sh
new file mode 100755
index 0000000..e9e7cfe
--- /dev/null
+++ b/scripts/benchmark.sh
@@ -0,0 +1,96 @@
+#!/usr/bin/env bash
+#
+# benchmark.sh benchmarks go-cacher + go-cacher-server.
+#
+# It runs three types of benchmarks:
+#
+# - cold; go-cacher and go-cacher-server both start with a cold cache.
+# - warm; go-cacher and go-cacher-server both start with a warm cache.
+# - http; go-cacher starts with a cold cache, go-cacher-server starts with a warm cache.
+#
+# Usage:
+#   ./scripts/benchmark.sh [<go cmd>]
+#
+# Environment variables:
+#   LATENCIES: Comma-separated list of latencies (as Go duration strings) to run go-cacher-server with. Default: 0
+#   TESTS: Comma-separated list of tests to run. Options are: cold, warm, http. Default: cold,warm,http
+
+set -euo pipefail
+
+GOCMD="${@:-go build ./...}"
+TESTS="${TESTS:-cold,warm,http}"
+IFS=',' read -ra LATENCY_ARRAY <<< "${LATENCIES:-0}"
+
+which go-cacher > /dev/null 2>&1 || go install github.com/bradfitz/go-tool-cache/cmd/go-cacher@latest
+which go-cacher-server > /dev/null 2>&1 || go install github.com/bradfitz/go-tool-cache/cmd/go-cacher-server@latest
+
+export RUN_DIR=$(mktemp -d)
+
+cleanup() {
+    stop_server
+    rm -rf "$RUN_DIR"
+}
+trap cleanup EXIT SIGTERM SIGINT
+
+ensure_server() {
+    if [ -f "$RUN_DIR/server.pid" ]; then
+        return
+    fi
+
+    go-cacher-server -verbose -inject-latency="${LATENCY}" -cache-dir="$(mktemp -d -p "$RUN_DIR" srv_cache_XXXX)" > "/tmp/server.log" 2>&1 &
+    echo $! > "$RUN_DIR/server.pid"
+}
+
+stop_server() {
+    if [ -f "$RUN_DIR/server.pid" ]; then
+        kill $(cat "$RUN_DIR/server.pid") 2>/dev/null || true
+        rm -f "$RUN_DIR/server.pid"
+    fi
+}
+
+ensure_cold_server() {
+    stop_server
+    ensure_server
+}
+
+for l in "${LATENCY_ARRAY[@]}"; do
+    export LATENCY="$l"
+    echo "---- LATENCY=${LATENCY} ----"
+    echo ""
+
+    if [[ "${TESTS}" == *"cold"* ]]; then
+        ensure_cold_server
+
+        echo "Testing with cold cache..."
+        start=$(date +%s%N)
+        GOCACHEPROG="go-cacher -verbose -cache-dir=$(mktemp -d -p "$RUN_DIR" cmd_cache_XXXX) -cache-server=http://localhost:31364" eval "$GOCMD"
+        dur=$(( ($(date +%s%N) - start) / 1000000 ))
+        echo "Cold run took ${dur}ms"
+        echo ""
+    fi
+
+    if [[ "${TESTS}" == *"warm"* ]]; then
+        export CMD_CACHE_DIR="$(mktemp -d -p "$RUN_DIR" cmd_cache_XXXX)"
+        ensure_server
+        GOCACHEPROG="go-cacher -cache-dir=$CMD_CACHE_DIR -cache-server=http://localhost:31364" eval "$GOCMD"
+
+        echo "Testing with warm HTTP and disk cache..."
+        start=$(date +%s%N)
+        GOCACHEPROG="go-cacher -verbose -cache-dir=$CMD_CACHE_DIR -cache-server=http://localhost:31364" eval "$GOCMD"
+        dur=$(( ($(date +%s%N) - start) / 1000000 ))
+        echo "Warm run took ${dur}ms"
+        echo ""
+    fi
+
+    if [[ "${TESTS}" == *"http"* ]]; then
+        ensure_server
+        GOCACHEPROG="go-cacher -cache-dir=$(mktemp -d -p "$RUN_DIR" cmd_cache_XXXX) -cache-server=http://localhost:31364" eval "$GOCMD"
+
+        echo "Testing with warm HTTP cache only..."
+        start=$(date +%s%N)
+        GOCACHEPROG="go-cacher -verbose -cache-dir=$(mktemp -d -p "$RUN_DIR" cmd_cache_XXXX) -cache-server=http://localhost:31364" eval "$GOCMD"
+        dur=$(( ($(date +%s%N) - start) / 1000000 ))
+        echo "HTTP run took ${dur}ms"
+        echo ""
+    fi
+done