Cloud Native Buildpacks

Cloud Native Buildpacks enable building a container image from source code without the need for a Dockerfile.

Skaffold supports building with Cloud Native Buildpacks, requiring only a local Docker daemon. Skaffold performs the build inside a container using the builder specified in the buildpack config.

On successful build completion, the built image will be pushed to the remote registry. You can choose to skip this step.

Configuration

To use Buildpacks, add a buildpack field to each artifact you specify in the artifacts part of the build section. context should be a path to your source.

The following options can optionally be configured:

Option Description Default
builder Required builder image used.
runImage overrides the stack’s default run image.
env environment variables, in the key=value form, passed to the build. Values can use the go template syntax. []
buildpacks a list of strings, where each string is a specific buildpack to use with the builder. If you specify buildpacks the builder image automatic detection will be ignored. These buildpacks will be used to build the Image from your source code. Order matters. []
trustBuilder indicates that the builder should be trusted. false
projectDescriptor path to the project descriptor file. project.toml
dependencies file dependencies that skaffold should watch for both rebuilding and file syncing for this artifact.
volumes support mounting host volumes into the container.

Builder

builder is required and tells Skaffold which Builder to use.

Run Image

runImage is optional and will override the default Run Image.

Artifact Dependency

You can define dependency on other artifacts using the requires keyword. This can be useful to specify another artifact image as the builder or runImage.

build:
  artifacts:
  - image: image1 # buildpacks artifact
    buildpacks:
      builder: image2
      runImage: image3
    requires:
      - image: image2
      - image: image3
  - image: image2 # builder artifact
  - image: image3 # run image artifact
  local: {}

User defined environment variables

env makes it possible to configure specific environment variables for buildpacks. Many buildpacks use environment variables to adjust their detection and the build phases, such as selecting specific versions of language runtimes. Note that user’s current environment is not passed through to buildpacks.

Example

The following build section, instructs Skaffold to build a Docker image with buildpacks:

apiVersion: skaffold/v2beta5
kind: Config
build:
  artifacts:
  - image: gcr.io/k8s-skaffold/skaffold-buildpacks
    buildpacks:
      builder: "gcr.io/buildpacks/builder:v1"

Dependencies

dependencies tells the skaffold file watcher which files should be watched to trigger rebuilds and file syncs. Supported schema for dependencies includes:

Option Description Default
paths should be set to the file dependencies for this artifact, so that the skaffold file watcher knows when to rebuild and perform file synchronization. []
ignore specifies the paths that should be ignored by skaffold’s file watcher. If a file exists in both paths and in ignore, it will be ignored, and will be excluded from both rebuilds and file synchronization. Will only work in conjunction with paths. []

By default, every file in the artifact’s context will be watched.

Paths and Ignore

Paths and Ignore are arrays used to list dependencies. Any paths in Ignore will be ignored by the skaffold file watcher, even if they are also specified in Paths. Ignore will only work in conjunction with Paths, and with none of the other custom artifact dependency types.

buildpack:
  builder: "gcr.io/buildpacks/builder:v1"
  dependencies:
    paths:
    - pkg/**
    - src/*.go
    ignore:
    - vendor/**
Last modified November 5, 2020: Update documentation for builders around artifact dependency. (#4998) (fd67ac10f)