feat(static): pass extra Go build flags, ldflags and tags

build-static.sh

@@ -16,6 +16,9 @@ set -o pipefail
 # - PHP_EXTENSIONS: comma-separated extensions (default: the list in craft.yml)
 # - PHP_EXTENSION_LIBS: comma-separated extra libraries (default: the list in craft.yml)
 # - XCADDY_ARGS: extra Caddy modules to pass to xcaddy (default: the list in craft.yml)
+# - GO_BUILD_FLAGS: extra flags to pass to go build (default: none)
+# - GO_LDFLAGS: extra Go linker flags, without double quotes (default: none)
+# - GO_TAGS: extra comma-separated Go build tags (default: none)
 # - FRANKENPHP_VERSION: FrankenPHP version (default: current Git commit)
 # - EMBED: path to the PHP app to embed (default: none)
 # - CLEAN: when set, rebuild everything from scratch (default: none)
@@ -213,6 +216,15 @@ while IFS= read -r line || [ -n "${line}" ]; do
 	*"SPC_CMD_VAR_FRANKENPHP_XCADDY_MODULES:"*)
 		[ -n "${XCADDY_ARGS}" ] && line="  SPC_CMD_VAR_FRANKENPHP_XCADDY_MODULES: \"${XCADDY_ARGS}\""
 		;;
+	*"SPC_CMD_VAR_FRANKENPHP_GO_BUILD_FLAGS:"*)
+		line="  SPC_CMD_VAR_FRANKENPHP_GO_BUILD_FLAGS: \"${GO_BUILD_FLAGS}\""
+		;;
+	*"SPC_CMD_VAR_FRANKENPHP_GO_LDFLAGS:"*)
+		line="  SPC_CMD_VAR_FRANKENPHP_GO_LDFLAGS: \"${GO_LDFLAGS}\""
+		;;
+	*"SPC_CMD_VAR_FRANKENPHP_GO_TAGS:"*)
+		line="  SPC_CMD_VAR_FRANKENPHP_GO_TAGS: \"${GO_TAGS}\""
+		;;
 	esac
 
 	printf '%s\n' "${line}" >>"${craft}"

craft.yml

@@ -30,6 +30,9 @@ download-options:
 
 extra-env:
   SPC_CMD_VAR_FRANKENPHP_XCADDY_MODULES: "--with github.com/dunglas/caddy-cbrotli --with github.com/dunglas/mercure/caddy --with github.com/dunglas/vulcain/caddy"
+  SPC_CMD_VAR_FRANKENPHP_GO_BUILD_FLAGS: ""
+  SPC_CMD_VAR_FRANKENPHP_GO_LDFLAGS: ""
+  SPC_CMD_VAR_FRANKENPHP_GO_TAGS: ""
   EXTENSION_DIR: "/usr/lib/frankenphp/modules"
   OPENSSLDIR: "/etc/ssl"
 

docs/embed.md

@@ -131,6 +131,20 @@ You can also run the PHP CLI scripts embedded in your binary:
 ./my-app php-cli bin/console
 ```
 
+## Extraction path
+
+At startup, the embedded app is extracted to a private temporary directory whose name changes
+with the content of the app. Some apps need a fixed path, for instance because they ship
+precompiled code referencing absolute paths, such as an OPcache file cache.
+Set it at build time with Go linker flags:
+
+```console
+EMBED=/path/to/your/app GO_LDFLAGS="-X github.com/dunglas/frankenphp.EmbeddedAppPath=/opt/my-app" ./build-static.sh
+```
+
+Files already present at this path are kept as is: it must only be writable by the user
+running the binary.
+
 ## PHP extensions
 
 By default, the script will build extensions required by the `composer.json` file of your project, if any.

docs/static.md

@@ -97,6 +97,20 @@ In this example, we add the [Souin](https://souin.io) HTTP cache module for Cadd
 > The cbrotli, Mercure, and Vulcain modules are included by default if `XCADDY_ARGS` is empty or not set.
 > If you customize the value of `XCADDY_ARGS`, you must include them explicitly if you want them to be included.
 
+### Go build flags
+
+To pass extra flags to the Go build, use the `GO_BUILD_FLAGS`, `GO_LDFLAGS` (linker flags, without double quotes) and `GO_TAGS` (comma-separated build tags) variables.
+Linker flags and tags are merged with the ones FrankenPHP needs:
+
+```console
+docker run --rm -v "$PWD/output:/output" -e OUTPUT_DIR=/output -e SPC_LOGS_DIR=/output/log \
+  -e GO_BUILD_FLAGS=-trimpath \
+  -e GO_LDFLAGS="-X github.com/dunglas/frankenphp.EmbeddedAppPath=/opt/my-app" \
+  dunglas/frankenphp:static-builder-musl
+```
+
+These variables are applied by static-php-cli (`SPC_CMD_VAR_FRANKENPHP_GO_*`), older versions ignore them.
+
 See also how to [customize the FrankenPHP static build](#customizing-the-frankenphp-static-build)
 
 ### GitHub token