Add support for ContainerSource

[rhuss]

Feature request

ContainerSource is back with knative/eventing#2755 in Eventing 0.14.0. As a built-in source we should support it out of the box.

[daisy-ycguo]

/assign
I would take a look at this feature.

[daisy-ycguo]

ContainerSource has a field Template corev1.PodTemplateSpec whose type is:

type PodTemplateSpec struct {
	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
	Spec PodSpec `json:"spec,omitempty" protobuf:"bytes,2,opt,name=spec"`
}

Although there are many fields in PodTemplateSpec, we could not support all fields as options. I would select some frequently used fields as container command options. Here are what I have selected:

• container name
• container image
• ImagePullPolicy
• Args
• Env

If you have more in your mind, we could discuss whether to support in the coming initial PR or in the future PRs. Thanks.

[rhuss]

I wonder whether we could 'reuse' the part from kn service create as this is also about setting up a PodSpec for the revision (so we could split out those options that are about specifying the pod teplates into a separate package and reuse it). This would have also the benefit that the UX would be uniform for kn service create and kn source container.

Or this might be not really what we want, as a pod specified here has no restrictions wrt/ number of containers/ports, etc.

What's about supporting the same set of options that kubectl run --generator=run-pod/v1 supports ?

[rhuss]

Thinking again, I believe its better to follow the kubectl syntax and maybe add an option -f that allows to import a PodTemplate from a YAML file (could be a plain Pod declaration)

[daisy-ycguo]

Here are kubectl run options

Options:
      --allow-missing-template-keys=true: If true, ignore any errors in
templates when a field or map key is missing in the template. Only applies to
golang and jsonpath output formats.
      --attach=false: If true, wait for the Pod to start running, and then
attach to the Pod as if 'kubectl attach ...' were called.  Default false, unless
'-i/--stdin' is set, in which case the default is true. With '--restart=Never'
the exit code of the container process is returned.
      --cascade=true: If true, cascade the deletion of the resources managed by
this resource (e.g. Pods created by a ReplicationController).  Default true.
      --command=false: If true and extra arguments are present, use them as the
'command' field in the container, rather than the 'args' field which is the
default.
      --dry-run=false: If true, only print the object that would be sent,
without sending it.
      --env=[]: Environment variables to set in the container
      --expose=false: If true, a public, external service is created for the
container(s) which are run
  -f, --filename=[]: to use to replace the resource.
      --force=false: Only used when grace-period=0. If true, immediately remove
resources from API and bypass graceful deletion. Note that immediate deletion of
some resources may result in inconsistency or data loss and requires
confirmation.
      --generator='': The name of the API generator to use, see
http://kubernetes.io/docs/user-guide/kubectl-conventions/#generators for a list.
      --grace-period=-1: Period of time in seconds given to the resource to
terminate gracefully. Ignored if negative. Set to 1 for immediate shutdown. Can
only be set to 0 when --force is true (force deletion).
      --hostport=-1: The host port mapping for the container port. To
demonstrate a single-machine container.
      --image='': The image for the container to run.
      --image-pull-policy='': The image pull policy for the container. If left
empty, this value will not be specified by the client and defaulted by the
server
  -l, --labels='': Comma separated labels to apply to the pod(s). Will override
previous values.
      --leave-stdin-open=false: If the pod is started in interactive mode or
with stdin, leave stdin open after the first attach completes. By default, stdin
will be closed after the first attach completes.
      --limits='': The resource requirement limits for this container.  For
example, 'cpu=200m,memory=512Mi'.  Note that server side components may assign
limits depending on the server configuration, such as limit ranges.
  -o, --output='': Output format. One of:
json|yaml|name|templatefile|template|go-template|go-template-file|jsonpath-file|jsonpath.
      --overrides='': An inline JSON override for the generated object. If this
is non-empty, it is used to override the generated object. Requires that the
object supply a valid apiVersion field.
      --pod-running-timeout=1m0s: The length of time (like 5s, 2m, or 3h, higher
than zero) to wait until at least one pod is running
      --port='': The port that this container exposes.  If --expose is true,
this is also the port used by the service that is created.
      --quiet=false: If true, suppress prompt messages.
      --record=false: Record current kubectl command in the resource annotation.
If set to false, do not record the command. If set to true, record the command.
If not set, default to updating the existing annotation value only if one
already exists.
  -R, --recursive=false: Process the directory used in -f, --filename
recursively. Useful when you want to manage related manifests organized within
the same directory.
  -r, --replicas=1: Number of replicas to create for this container. Default is
1.
      --requests='': The resource requirement requests for this container.  For
example, 'cpu=100m,memory=256Mi'.  Note that server side components may assign
requests depending on the server configuration, such as limit ranges.
      --restart='Always': The restart policy for this Pod.  Legal values
[Always, OnFailure, Never].  If set to 'Always' a deployment is created, if set
to 'OnFailure' a job is created, if set to 'Never', a regular pod is created.
For the latter two --replicas must be 1.  Default 'Always', for CronJobs
`Never`.
      --rm=false: If true, delete resources created in this command for attached
containers.
      --save-config=false: If true, the configuration of current object will be
saved in its annotation. Otherwise, the annotation will be unchanged. This flag
is useful when you want to perform kubectl apply on this object in the future.
      --schedule='': A schedule in the Cron format the job should be run with.
      --service-generator='service/v2': The name of the generator to use for
creating a service.  Only used if --expose is true
      --service-overrides='': An inline JSON override for the generated service
object. If this is non-empty, it is used to override the generated object.
Requires that the object supply a valid apiVersion field.  Only used if --expose
is true.
      --serviceaccount='': Service account to set in the pod spec
  -i, --stdin=false: Keep stdin open on the container(s) in the pod, even if
nothing is attached.
      --template='': Template string or path to template file to use when
-o=go-template, -o=go-template-file. The template format is golang templates
[http://golang.org/pkg/text/template/#pkg-overview].
      --timeout=0s: The length of time to wait before giving up on a delete,
zero means determine a timeout from the size of the object
  -t, --tty=false: Allocated a TTY for each container in the pod.
      --wait=false: If true, wait for resources to be gone before returning.
This waits for finalizers.

[daisy-ycguo]

and here are kn service create options:

Flags:
  -a, --annotation stringArray        Service annotation to set.
                                      name=value; you may provide this
                                      flag any number of times to set
                                      multiple annotations. To unset,
                                      specify the annotation name followed
                                      by a "-" (e.g., name-).
      --arg stringArray               Add argument to the container
                                      command. Example: --arg myArg1 --arg
                                      --myArg2 --arg myArg3=3. You can use
                                      this flag multiple times.
      --async                         DEPRECATED: please use --no-wait
                                      instead. Do not wait for 'service
                                      create' operation to be completed.
      --autoscale-window string       Duration to look back for making
                                      auto-scaling decisions. The service
                                      is scaled to zero if no request was
                                      received in during that time. (eg: 10s)
      --cluster-local                 Specify that the service be private.
                                      (--no-cluster-local will make the
                                      service publicly available)
      --cmd string                    Specify command to be used as
                                      entrypoint instead of default one.
                                      Example: --cmd /app/start or --cmd
                                      /app/start --arg myArg to pass
                                      aditional arguments.
      --concurrency-limit int         Hard Limit of concurrent requests to
                                      be processed by a single replica.
      --concurrency-target int        Recommendation for when to scale up
                                      based on the concurrent number of
                                      incoming request. Defaults to
                                      --concurrency-limit when given.
      --concurrency-utilization int   Percentage of concurrent requests
                                      utilization before scaling up.
                                      (default 70)
  -e, --env stringArray               Environment variable to set.
                                      NAME=value; you may provide this
                                      flag any number of times to set
                                      multiple environment variables. To
                                      unset, specify the environment
                                      variable name followed by a "-"
                                      (e.g., NAME-).
      --env-from stringArray          Add environment variables from a
                                      ConfigMap (prefix cm: or
                                      config-map:) or a Secret (prefix
                                      secret:). Example: --env-from
                                      cm:myconfigmap or --env-from
                                      secret:mysecret. You can use this
                                      flag multiple times. To unset a
                                      ConfigMap/Secret reference, append
                                      "-" to the name, e.g. --env-from
                                      cm:myconfigmap-.
      --force                         Create service forcefully, replaces
                                      existing service if any.
  -h, --help                          help for create
      --image string                  Image to run.
  -l, --label stringArray             Labels to set for both Service and
                                      Revision. name=value; you may
                                      provide this flag any number of
                                      times to set multiple labels. To
                                      unset, specify the label name
                                      followed by a "-" (e.g., name-).
      --label-revision stringArray    Revision label to set. name=value;
                                      you may provide this flag any number
                                      of times to set multiple labels. To
                                      unset, specify the label name
                                      followed by a "-" (e.g., name-).
                                      This flag takes precedence over
                                      "label" flag.
      --label-service stringArray     Service label to set. name=value;
                                      you may provide this flag any number
                                      of times to set multiple labels. To
                                      unset, specify the label name
                                      followed by a "-" (e.g., name-).
                                      This flag takes precedence over
                                      "label" flag.
      --limits-cpu string             The limits on the requested CPU
                                      (e.g., 1000m).
      --limits-memory string          The limits on the requested memory
                                      (e.g., 1024Mi).
      --lock-to-digest                Keep the running image for the
                                      service constant when not explicitly
                                      specifying the image.
                                      (--no-lock-to-digest pulls the image
                                      tag afresh with each new revision)
                                      (default true)
      --max-scale int                 Maximal number of replicas.
      --min-scale int                 Minimal number of replicas.
      --mount stringArray             Mount a ConfigMap (prefix cm: or
                                      config-map:), a Secret (prefix
                                      secret: or sc:), or an existing
                                      Volume (without any prefix) on the
                                      specified directory. Example:
                                      --mount /mydir=cm:myconfigmap,
                                      --mount /mydir=secret:mysecret, or
                                      --mount /mydir=myvolume. When a
                                      configmap or a secret is specified,
                                      a corresponding volume is
                                      automatically generated. You can use
                                      this flag multiple times. For
                                      unmounting a directory, append "-",
                                      e.g. --mount /mydir-, which also
                                      removes any auto-generated volume.
  -n, --namespace string              Specify the namespace to operate in.
      --no-cluster-local              Do not specify that the service be
                                      private. (--no-cluster-local will
                                      make the service publicly available)
                                      (default true)
      --no-lock-to-digest             Do not keep the running image for
                                      the service constant when not
                                      explicitly specifying the image.
                                      (--no-lock-to-digest pulls the image
                                      tag afresh with each new revision)
      --no-wait                       Do not wait for 'service create'
                                      operation to be completed.
  -p, --port int32                    The port where application listens on.
      --pull-secret string            Image pull secret to set. An empty
                                      argument ("") clears the pull
                                      secret. The referenced secret must
                                      exist in the service's namespace.
      --requests-cpu string           The requested CPU (e.g., 250m).
      --requests-memory string        The requested memory (e.g., 64Mi).
      --revision-name string          The revision name to set. Must start
                                      with the service name and a dash as
                                      a prefix. Empty revision name will
                                      result in the server generating a
                                      name for the revision. Accepts
                                      golang templates, allowing
                                      {{.Service}} for the service name,
                                      {{.Generation}} for the generation,
                                      and {{.Random [n]}} for n random
                                      consonants. (default
                                      "{{.Service}}-{{.Random
                                      5}}-{{.Generation}}")
      --service-account string        Service account name to set. An
                                      empty argument ("") clears the
                                      service account. The referenced
                                      service account must exist in the
                                      service's namespace.
      --user int                      The user ID to run the container
                                      (e.g., 1001).
      --volume stringArray            Add a volume from a ConfigMap
                                      (prefix cm: or config-map:) or a
                                      Secret (prefix secret: or sc:).
                                      Example: --volume
                                      myvolume=cm:myconfigmap or --volume
                                      myvolume=secret:mysecret. You can
                                      use this flag multiple times. To
                                      unset a ConfigMap/Secret reference,
                                      append "-" to the name, e.g.
                                      --volume myvolume-.
      --wait                          Wait for 'service create' operation
                                      to be completed. (default true)
      --wait-timeout int              Seconds to wait before giving up on
                                      waiting for service to be ready.
                                      (default 600)

[rhuss]

I would just start with:

• --image
• --env
• --label
• --annotation
• --service-account

[rhuss]

we always can add more later (and also check for synergy with kn service)