node-function-buildpack

README

node-function-buildpack

The Node Function Buildpack is a Cloud Native Buildpack V3 that provides the riff Node Function Invoker to functions.

This buildpack is designed to work in collaboration with other buildpacks, which are tailored to support (and know how to build / run) languages supported by riff.

In Plain English

In a nutshell, when combined with the other buildpacks present in the riff builder what this means (and especially when dealing with the riff CLI which takes care of the creation of the riff.toml file for you):

• The presence of a package.json file and/or the fact that the --artifact flag points to a .js file will result in
  1. the npm installation (or yarn installation) of the function if applicable
  2. the execution as a node function thanks to the node invoker
• Ambiguity in the detection process will result in a build failure
• The presence of the --invoker flag will entirely bypass the detection mechanism and force a given language/invoker

Detailed Buildpack Behavior

Detection Phase

Detection passes if

• a $APPLICATION_ROOT/riff.toml exists and
• the build plan already contains a npm key (typically because an NPM based application was detected by the npm buildpack)
  1. alternatively, if the file pointed to by the artifact value in riff.toml exists and has a .js extension

If detection passes, the buildpack will add a riff-invoker-node key and fn metadata extracted from the riff metadata.

If several languages are detected simultaneously, the detect phase errors out. The override key in riff.toml can be used to bypass detection and force the use of a particular invoker.

Build Phase

If a node function has been detected

• Contributes the riff Node Invoker to a launch layer, set as the main node entry point with FUNCTION_URI = <artifact> set as an environment variable. Note that artifact may actually be empty, in which case the invoker will require() the current directory (the function), which in turn expects that it contains a valid package.json file with its main entry point set.

The function behavior is exposed via standard buildpack process types:

• Contributes web process
• Contributes function process

Bindings

The buildpack optionally accepts the following bindings during the build phase:

Type: dependency-mapping

Key	Value	Description
<dependency-digest>	<uri>	If needed, the buildpack will fetch the dependency with digest <dependency-digest> from <uri>

How to Build

Prerequisites

To build the node-function-buildpack you'll need

• Go 1.13+
• to run acceptance tests:
  • a running local docker daemon
• for local function builds
  • the pack command line tool

You can build the buildpack by running

make

This will package (with pre-downloaded cache layers) the buildpack in the artifactory/io/projectriff/node/io.projectriff.node/latest directory. That can be used as a uri in a builder.toml file of a builder (see https://github.com/projectriff/builder)

License

This buildpack is released under version 2.0 of the Apache License.