Package kn in a container image

[imjasonh]

This would enable users of Tekton and Google Cloud Build to more easily invoke kn, e.g.:

...
steps
- name: kn-deploy-image
  image: gcr.io/knative-something/kn:v0.X.Y
  command: ['kn', 'service', 'update', 'foo', '--image', 'gcr.io/my/image']
...

Assuming kn doesn't depend on any other tools, you could build and push the image using ko publish (and crane copy to shorten the image name):

$ KO_DOCKER_REPO=gcr.io/knative-something/ ko publish -P github.com/knative/client/cmd/kn
$ crane copy gcr.io/knative-something/github.com/knative/client/cmd/kn gcr.io/knative-something/kn:${RELEASE}

[imjasonh]

Related: #52 #53

It'd be great to get nightly-built images tagged with the latest commit SHA (or just :latest), and release-tagged images built during releases.

[houshengbo]

We can directly run the command "ko publish github.com/knative/client/cmd/kn -B -t ${tag}" to name the image <KO_DOCKER_REPO>/kn in the image registry. No need of crane copy.

We can define <KO_DOCKER_REPO> as gcr.io/[gcloud-project], docker.io/, etc. So where do we put this image officially for knative client? Do we have a public directory somewhere to host knative images?

[houshengbo]

I have succeeded in creating the image in my own dockerhub repository, docker.io/houshengbo/kn:latest, with the command:

ko publish github.com/knative/client/cmd/kn -B -t latest

When I pulled the image, and did the taskrun run for the following section:

steps
- name: kn-deploy-image
  image: docker.io/houshengbo/kn:latest
  command: ['kn', 'service', 'create', 'foo', '--image', 'gcr.io/knative-samples/helloworld-go', '--env', 'TARGET=Knative']

I have got:

Error executing command: exec: "kn": executable file not found in $PATH

I was wondering what I have done wrong or I am missing. @imjasonh Do you have any ideas? Thx.

[rhuss]

@houshengbo just shot in the dark, but could you use ./kn instead of plain kn ? Thoug, I'm not sure what working directory ko sets for the generated image, nor what working directory Tekton is using.

[houshengbo]

It looks like I need to install crane first to check the path of kn. This is what I have done:

go get github.com/google/go-containerregistry/cmd/crane

crane should be install under $GOPATH/bin.

Then run

crane config ${image}

Here is the output for the image of kn:

{"architecture":"amd64","author":"Bazel","created":"1970-01-01T00:00:00Z","history":[{"author":"Bazel","created":"1970-01-01T00:00:00Z","created_by":"bazel build ..."},{"created":"0001-01-01T00:00:00Z"},{"created":"0001-01-01T00:00:00Z"}],"os":"linux","rootfs":{"type":"layers","diff_ids":["sha256:01092e5921c5543a918d54d9df752ee09a84c912a1d914b7eb37e7152f20b951","sha256:8f8d58d9708807553434fbd82014ea40b5ee0dc8b2eeefcde561a363461d3e66","sha256:0d411545791d984190d7488cad58d30fa9ae1aec52eda3262d65ecd1aa58d1dc"]},"config":{"AttachStderr":false,"AttachStdin":false,"AttachStdout":false,"Cmd":null,"Healthcheck":null,"Domainname":"","Entrypoint":["/ko-app/kn"],"Env":["PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin","SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt","KO_DATA_PATH=/var/run/ko"],"Hostname":"","Image":"","Labels":null,"OnBuild":null,"OpenStdin":false,"StdinOnce":false,"Tty":false,"User":"","Volumes":null,"WorkingDir":"","ExposedPorts":null,"ArgsEscaped":false,"NetworkDisabled":false,"MacAddress":"","StopSignal":"","Shell":null},"container_config":{"AttachStderr":false,"AttachStdin":false,"AttachStdout":false,"Cmd":null,"Healthcheck":null,"Domainname":"","Entrypoint":null,"Env":null,"Hostname":"","Image":"","Labels":null,"OnBuild":null,"OpenStdin":false,"StdinOnce":false,"Tty":false,"User":"","Volumes":null,"WorkingDir":"","ExposedPorts":null,"ArgsEscaped":false,"NetworkDisabled":false,"MacAddress":"","StopSignal":"","Shell":null}}

The most important thing we need to look up is Entrypoint":["/ko-app/kn"], which tells us the path of the command.

I will try /ko-app/kn instead of kn to see how it goes. Thanks to @imjasonh.

[houshengbo]

/assign @houshengbo

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[sixolet]

We have it now!

[imjasonh]

That's gcr.io/knative-releases/github.com/knative/client/cmd/kn correct?

[rhuss]

Yes. With the gotcha that kn version is broken (we need to propagate ldflags to ko) --> #257