cnbp

Overview

This repository houses a barebones BuildKit frontend for Cloud Native Buildpacks. Note that it's Linux only since BuildKit doesn't support Windows yet. Frontend aims to implement Platform API 0.5, but is not there yet.

How to try it

• Make sure that BuildKit is enabled in your daemon
• Clone CNBP samples repository
• Add the following lines to the project.toml. builder corresponds to --builder flag of pack build <image-name> [flags] invocation.

# syntax = erichripko/cnbp
[io.buildpacks.build]
builder = "some-builder"

• Build it

$ docker build -t sample .
[+] Building 80.8s (28/28) FINISHED
 => [internal] load build definition from Dockerfile                                                               0.1s
 => => transferring dockerfile: 173B                                                                               0.0s
 => [internal] load .dockerignore                                                                                  0.0s
 => => transferring context: 2B                                                                                    0.0s
 => resolve image config for docker.io/erichripko/cnbp:latest                                                      0.0s
 => CACHED docker-image://docker.io/erichripko/cnbp:latest                                                         0.0s
 => [internal] load build definition from Dockerfile                                                               0.0s
 => => transferring dockerfile: 173B                                                                               0.0s
 => load metadata for docker.io/paketobuildpacks/builder:full                                                      0.0s
 => [internal] load context                                                                                        0.1s
 => => transferring context: 87.94kB                                                                               0.0s
 => Builder is paketobuildpacks/builder:full                                                                       0.6s
 => Load sources                                                                                                   0.2s
 => Detection                                                                                                      1.2s
 => Load group definition                                                                                          0.2s
 => Load plan definition                                                                                           0.2s
 => Build                                                                                                         41.2s
 => load metadata for docker.io/paketobuildpacks/run:full-cnb                                                      1.4s
 => Run image is index.docker.io/paketobuildpacks/run:full-cnb                                                    30.0s
 => Exporting launcher                                                                                             1.0s
 => Exporting buildpack layer /layers/paketo-buildpacks_ca-certificates/helper                                     0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/helper                                   0.2s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/java-security-properties                 0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/jre                                      0.5s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/jvmkill                                  0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_executable-jar/classpath                                   0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/helper                                         0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/spring-cloud-bindings                          0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/web-application-type                           0.1s
 => Exporting app layer                                                                                            0.2s
 => Exporting build metadata                                                                                       0.2s
 => exporting to image                                                                                             0.9s
 => => exporting layers                                                                                            0.8s
 => => writing image sha256:321aa7926a9e38422f53a1ebcfff5e32af9dcff4788e825199140eeb5d5e38a6                       0.0s
 => => naming to docker.io/library/sample                                                                          0.0s

• Run the application: docker run --rm -d -p 8080:8080 sample /cnb/lifecycle/launcher
• Observe that it works as expected

$ curl http://localhost:8080
...
        <h1>Hello, Buildpacker!</h1>
    </div>
</body>
</html>

Setting environment variables

Buildpacks support configuration via build-time environment variables. These are mapped to build args in Docker, meaning that you can either:

• Set them on CLI with --build-arg argument
• Set them in Compose with args: attribute

For example, we can configure JVM version (see paketo Buildpacks docs):

$ docker build -t sample --build-arg BP_JVM_VERSION=8 .
[+] Building 39.1s (29/29) FINISHED
 => [internal] load build definition from Dockerfile                                                               0.1s
 => => transferring dockerfile: 110B                                                                               0.0s
 => [internal] load .dockerignore                                                                                  0.0s
 => => transferring context: 2B                                                                                    0.0s
 => resolve image config for docker.io/erichripko/cnbp:latest                                                      0.0s
 => CACHED docker-image://docker.io/erichripko/cnbp:latest                                                         0.0s
 => [internal] load build definition from Dockerfile                                                               0.0s
 => => transferring dockerfile: 110B                                                                               0.0s
 => load metadata for docker.io/paketobuildpacks/builder:full                                                      0.0s
 => [internal] load context                                                                                        0.0s
 => => transferring context: 4.16kB                                                                                0.0s
 => Builder is paketobuildpacks/builder:full                                                                       0.0s
 => CACHED Load sources                                                                                            0.0s
 => CACHED Set BP_JVM_VERSION=8                                                                                    0.0s
 => CACHED Detection                                                                                               0.0s
 => CACHED Load group definition                                                                                   0.0s
 => CACHED Load plan definition                                                                                    0.0s
 => Build                                                                                                         32.0s
 => load metadata for docker.io/paketobuildpacks/run:full-cnb                                                      0.0s
 => CACHED Run image is index.docker.io/paketobuildpacks/run:full-cnb                                              0.0s
 => Exporting launcher                                                                                             0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_ca-certificates/helper                                     0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/helper                                   0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/java-security-properties                 0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/jre                                      0.8s
 => Exporting buildpack layer /layers/paketo-buildpacks_bellsoft-liberica/jvmkill                                  0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_executable-jar/classpath                                   0.2s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/helper                                         0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/spring-cloud-bindings                          0.1s
 => Exporting buildpack layer /layers/paketo-buildpacks_spring-boot/web-application-type                           0.1s
 => Exporting app layer                                                                                            0.2s
 => Exporting build metadata                                                                                       0.1s
 => exporting to image                                                                                             1.3s
 => => exporting layers                                                                                            1.3s
 => => writing image sha256:7342883afc5ad3c62de8076ecb1261e75aa31ec4336d8af9b35c354368392334                       0.0s
 => => naming to docker.io/library/sample                                                                          0.0s

If you inspect Java in the container, you will see that it's indeed version 8:

$ java -version
openjdk version "1.8.0_282"
OpenJDK Runtime Environment (build 1.8.0_282-b08)
OpenJDK 64-Bit Server VM (build 25.282-b08, mixed mode)

Caching

Layers that have cache=true will be stored in BuildKit build-time cache. For example:

$ docker build -t sample .
[+] Building 59.1s (33/33) FINISHED
...
$ echo bust > file
$ docker build -t sample .
[+] Building 32.2s (33/33) FINISHED
...
#13 Analyze
#13 sha256:bc95079754ce8087237b9e4b8b24413ba96328b79315060ed65064ade1dfa692
#13 2.178 Previous image with name "this-image-definitely-does-not-exist" not found
#13 2.598 Restoring metadata for "paketo-buildpacks/bellsoft-liberica:jdk" from cache
#13 2.599 Restoring metadata for "paketo-buildpacks/maven:application" from cache
#13 2.600 Restoring metadata for "paketo-buildpacks/maven:cache" from cache
#13 DONE 2.7s

#14 Restore
#14 sha256:1095e4ee229fee1a92fcb17a9bd16c164d5e61270d9341835d14b086954ec1ac
#14 0.443 Restoring data for "paketo-buildpacks/bellsoft-liberica:jdk" from cache
#14 0.445 Restoring data for "paketo-buildpacks/maven:application" from cache
#14 0.445 Restoring data for "paketo-buildpacks/maven:cache" from cache
#14 DONE 3.0s
...
#15 Build
#15 sha256:373931a74c93e2a8a589f93437fdf5deeb670228a5d6fc0b30551812cadb6305
#15 0.778
...
#15 0.880   BellSoft Liberica JDK 11.0.10: Reusing cached layer
...

Note that build-time cached can be wiped by running docker builder prune.