Merge pull request #130 from rajatvig/add-download-config-option

feat: add download configuration option to support pre-installed binaries

Author: mcncl

README.md

@@ -281,6 +281,30 @@ steps:
                 trigger: "deploy-foo-service"
 ```
 
+### `download` (optional)
+
+Default: `true`
+
+By setting `download` to `false`, the plugin will use a pre-installed binary instead of downloading it on each run. The binary `monorepo-diff-buildkite-plugin` must be available in your PATH (typically `/usr/bin`).
+
+This option is useful for:
+- Reducing build time by avoiding repeated downloads
+- Improving security by using pre-vetted binaries
+- Organizations with policies against runtime binary downloads
+
+```yaml
+steps:
+  - label: "Triggering pipelines"
+    plugins:
+      - monorepo-diff#v1.6.0:
+          download: false
+          diff: "git diff --name-only HEAD~1"
+          watch:
+            - path: "foo-service/"
+              config:
+                trigger: "deploy-foo-service"
+```
+
 ### `hooks` (optional)
 
 Currently supports a list of `commands` you wish to execute after the `watched` pipelines have been triggered

docker-compose.yml

@@ -0,0 +1,5 @@
+services:
+  tests:
+    image: buildkite/plugin-tester:latest
+    volumes:
+      - .:/plugin

hooks/command

@@ -100,7 +100,7 @@ get_version() {
   else
     _version=""
   fi
-    
+
   RETVAL="$_version"
 }
 
@@ -152,8 +152,25 @@ download_binary_and_run() {
 
   # todo: move it to a more secure place
   chmod +x "${executable}"
-  
+
   ./"${executable}"
 }
 
-download_binary_and_run "$@" || exit 1
+run_preinstalled_binary() {
+  local _executable="monorepo-diff-buildkite-plugin"
+
+  if ! check_cmd "$_executable"; then
+    err "Binary '$_executable' not found in PATH. Please install it or set download: true"
+  fi
+
+  ${_executable} "$@"
+}
+
+# Check if download option is disabled (default is true for backward compatibility)
+download_enabled="${BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD:-true}"
+
+if [[ "$download_enabled" == "false" ]]; then
+  run_preinstalled_binary "$@" || exit 1
+else
+  download_binary_and_run "$@" || exit 1
+fi

plugin.yml

@@ -7,6 +7,8 @@ configuration:
   properties:
     diff:
       type: string
+    download:
+      type: boolean
     log_level:
       type: string
     interpolation:

tests/command.bats

@@ -0,0 +1,96 @@
+#!/usr/bin/env bats
+
+load "$BATS_PLUGIN_PATH/load.bash"
+
+# Uncomment the following line to debug stubbed commands
+# export COMMAND_STUB_DEBUG=/dev/tty
+
+setup() {
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_BUILDKITE_PLUGIN_TEST_MODE=true
+  # Set a minimal plugin config (only used by Go binary, not the bash hook's download logic)
+  export BUILDKITE_PLUGINS='[{"monorepo-diff": {}}]'
+  
+  # Create a mock binary in the current directory for download mode tests
+  cat > "$PWD/monorepo-diff-buildkite-plugin" << 'MOCKBIN'
+#!/bin/bash
+echo "Mock binary executed with args: $@"
+MOCKBIN
+  chmod +x "$PWD/monorepo-diff-buildkite-plugin"
+}
+
+teardown() {
+  # Clean up the mock binary
+  rm -f "$PWD/monorepo-diff-buildkite-plugin"
+}
+
+@test "download=false with binary in PATH succeeds" {
+  # Buildkite sets this env var based on plugin config
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD=false
+  export PATH="$PWD:$PATH"
+
+  run "$PWD/hooks/command"
+
+  assert_success
+  assert_output --partial "Mock binary executed"
+}
+
+@test "download=false without binary in PATH fails with error" {
+  # Buildkite sets this env var based on plugin config
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD=false
+  
+  # Remove mock binary from current directory and don't add to PATH
+  rm -f "$PWD/monorepo-diff-buildkite-plugin"
+  export PATH="/usr/bin:/bin"
+
+  run "$PWD/hooks/command"
+
+  assert_failure
+  assert_output --partial "Binary 'monorepo-diff-buildkite-plugin' not found in PATH"
+  assert_output --partial "Please install it or set download: true"
+}
+
+@test "download=true executes binary in test mode" {
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD=true
+
+  # In test mode, it skips download but still executes the mock binary we created
+  run "$PWD/hooks/command"
+
+  assert_success
+  assert_output --partial "Mock binary executed"
+}
+
+@test "download defaults to true when not set" {
+  # Don't set BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD - should default to true
+
+  # Should default to true, skip download in test mode, and execute mock binary
+  run "$PWD/hooks/command"
+
+  assert_success
+  assert_output --partial "Mock binary executed"
+}
+
+@test "download=false passes arguments to preinstalled binary" {
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD=false
+  export PATH="$PWD:$PATH"
+
+  run "$PWD/hooks/command" arg1 arg2
+
+  assert_success
+  assert_output --partial "Mock binary executed with args: arg1 arg2"
+}
+
+@test "download=true in test mode skips actual download" {
+  export BUILDKITE_PLUGIN_MONOREPO_DIFF_DOWNLOAD=true
+
+  # Stub curl to verify it's NOT called in test mode
+  stub curl \
+    ": echo 'ERROR: curl should not be called in test mode'; exit 1"
+
+  run "$PWD/hooks/command"
+
+  # Should succeed without calling curl
+  assert_success
+  
+  # Clean up stub (it should not have been called)
+  unstub curl || true
+}