Go Build Cloud Native Buildpack

The Go Build CNB executes the go build compilation process for Go programs. The buildpack builds the source code in the application directory into an executable and sets it as the start command for the image.

Integration

The Go Build CNB does not provide any dependencies. However, in order to execute the go build compilation process, the buildpack requires the go dependency that can be provided by a buildpack like the Go Distribution CNB.

Usage

To package this buildpack for consumption:

$ ./scripts/package.sh

This builds the buildpack's Go source using GOOS=linux by default. You can supply another value as the first argument to package.sh.

Go Build Configuration

Please set the following environment variables at build time either directly (ex. pack build my-app --env BP_ENVIRONMENT_VARIABLE=some-value) or through a project.toml file

BP_GO_BUILD_LDFLAGS

The BP_GO_BUILD_LDFLAGS variable allows you to set a value for the -ldflags build flag when compiling your program.

BP_GO_BUILD_LDFLAGS= -X main.variable=some-value

BP_GO_TARGETS

The BP_GO_TARGETS variable allows you to specify multiple programs to be compiled. The first target will be used as the start command for the image.

BP_GO_TARGETS=./cmd/web-server:./cmd/debug-server

BP_GO_BUILD_FLAGS

The BP_GO_BUILD_FLAGS variable allows you to override the default build flags when compiling your program.

BP_GO_BUILD_FLAGS= -buildmode=default -tags=paketo -ldflags="-X main.variable=some-value"

BP_GO_BUILD_IMPORT_PATH

The BP_GO_BUILD_IMPORT_PATH allows you to specify an import path for your application. This is necessary if you are building a $GOPATH application that imports its own sub-packages.

BP_GO_BUILD_IMPORT_PATH= example.com/some-app

BP_GO_WORK_USE

The BP_GO_WORK_USE variable allows you to initialise a workspace file and add modules to it. This is helpful for building submodules which use relative replace directives and go.work is not checked in. Usually, this is set together with BP_GO_TARGETS.

BP_GO_WORK_USE=./cmd/controller:./cmd/webhook

BP_GO_WORKDIR

The BP_GO_WORKDIR specifies a subdirectory (relative to the app root) which will be used as build working directory. This is where the main go package lives. For most applications, it is the root directory and this variable is not needed; this is useful for monorepos or non-standard applications. The difference between BP_GO_TARGETS is that it specifies nested targets to build while this var changes the directory for building and builds from there.

BP_GO_WORKDIR=subdir/path/to/main

BP_KEEP_FILES

The BP_KEEP_FILES variable allows to you to specity a path list of files (including file globs) that you would like to appear in the workspace of the final image. This will allow you to perserve static assests.

BP_KEEP_FILES=assets/*:public/*