Error is called when an error is encountered.

InstallTarballIfNotCached installs a runtime tarball hosted on dl.google.com into the provided layer with caching. Returns true if a cached layer is u

IsFlex returns true if the buildpack target platform is flex

OSForStack returns the Operating System being used by input stackID.

TestDetectWithStack is a helper for testing a buildpack's implementation of bin/detect which allows setting a custom stack name. This MUST be called f

AddProcess adds the given command as named process, overwriting any previous process with the same name.

BuildpackID returns the buildpack id.

FilterFailureTests returns a new slice with only tests that should be run. Tests are filtered out if their VersionInclusionConstraint does not match t

ReadNodeDependencies looks for a package.json and lockfile in either appDir or rootDir. The lockfile must either be in the same directory as package.j

Build serves as a common builder for App Engine buildpacks.

BuildpackVersion returns the buildpack version.

Enabled indicates that the builder is running in Development mode.

IsGCF returns true if the buildpack target platform is gcf.

ReadAndValidateFromFile converts the provided file into an AppHostingSchema. Returns an empty AppHostingSchema{} if the file does not exist.

Rename is a pass through for os.Rename(...) and logs an informational statement and returns any error with proper user / system attribution

SetFunctionsEnvVars sets launch-time functions environment variables.

StackID returns the stack id.

WithApplicationRoot sets the application root in Context.

Add adds the key-value to the cache for the given layer for future builds.

AddLabel adds a label to the user's application container.

ApplicationDirectory looks up the path to the application directory from the environment. Returns the application root by default.

CommonBuildpacks returns a map of common buildpacks that are used by all language runtimes.

CreateFile is a pass through for os.Create(...) and returns any error with proper user / system attribution

FailedFrameworkBuildError creates a FahError belonging to the class of errors that occur when the framework build command fails.

HashAndCheck computes a hash value according to the cache options provided and checks if there is a cache hit or miss by looking at the provided layer

HomeDir returns the path of the $USER's $HOME directory.

IsFAH returns true if the buildpack target platform is fah.

MaybeCopyPathContents recursively copies the contents of srcPath to destPath.

MetadataAdded returns the builder metadata after the buildpack phase was executed.

PackagePresent checks if a given package is present in the requirements file.

RunBuild is a helper for testing a buildpack's implementation of /bin/build. This MUST be called from a test function with the stub `func TestBuild(t

Tipf emits a structured logging line for usage tips.

WithFile sets the path of a file the server should send as a response.

WithMessageProducer sets a custom MessageProducer to produce the error message.

WithTestName specifies the test case name if a table-driven test is being used. This is important when invoking the test binary again as a child proce