Improve ko run

[jonjohnsonjr]

Shift the UX closer to go run than kubectl run.

This also adds some flags to make ko run spin up a pod, attach logs, and automatically clean itself up.

This drops the ability to override kubectl flags, but if you're going to do that I'd say just use some yaml 🤷‍♂.

Edit: Matt pointed out that you can just do kubectl run --name=$(ko publish IMPORTPATH) if you want to control flags, which is really nice. I'm happy with keeping ko run as just easy defaults.

Fixes #5

$ ko run ./cmd/ko -- run -h
2019/08/16 11:25:06 Building github.com/google/ko/cmd/ko
2019/08/16 11:25:12 Using base gcr.io/distroless/static:latest for github.com/google/ko/cmd/ko
2019/08/16 11:25:13 Publishing gcr.io/jonjohnson-test/ko/ko-099ba5bcefdead87f92606265fb99ac0:latest
2019/08/16 11:25:13 existing blob: sha256:72164b581b02b1eb297b403bcc8fc1bfa245cb52e103a3a525a0835a58ff58e2
2019/08/16 11:25:13 existing blob: sha256:e8d8785a314f385d3675a017f4e2df1707c528c06e7a7989663fdab4900bd8ff
2019/08/16 11:25:15 pushed blob: sha256:0fae946271ba011f82900b97d708352ba63d25a49e12e6a9e80779605b053400
2019/08/16 11:25:17 pushed blob: sha256:1519142143763d5f96d3cbb4b57d725a71f3c12e924b4492b3a0a45abbc5c530
2019/08/16 11:25:18 gcr.io/jonjohnson-test/ko/ko-099ba5bcefdead87f92606265fb99ac0:latest: digest: sha256:8c6a1882da175b22a7ae8dbc05c804b7538fd8c9a914c97b81a731f8a58d3f3c size: 751
2019/08/16 11:25:18 Published gcr.io/jonjohnson-test/ko/ko-099ba5bcefdead87f92606265fb99ac0@sha256:8c6a1882da175b22a7ae8dbc05c804b7538fd8c9a914c97b81a731f8a58d3f3c
2019/08/16 11:25:18 Running "github.com/google/ko/cmd/ko"
2019/08/16 11:25:19 $ kubectl run ko-099ba5bcefdead87f92606265fb99ac0 --image gcr.io/jonjohnson-test/ko/ko-099ba5bcefdead87f92606265fb99ac0@sha256:8c6a1882da175b22a7ae8dbc05c804b7538fd8c9a914c97b81a731f8a58d3f3c --generator=run-pod/v1 --attach --rm --restart=Never --log-flush-frequency=1s -- run -h
This sub-command combines "ko publish" and "kubectl run" to support containerizing and running Go binaries on Kubernetes in a single command.

Usage:
  ko run IMPORTPATH [flags]

Examples:

  # Publish the --image and run it on Kubernetes as:
  #   ${KO_DOCKER_REPO}/<package name>-<hash of import path>
  # When KO_DOCKER_REPO is ko.local, it is the same as if
  # --local and --preserve-import-paths were passed.
  ko run github.com/foo/bar/cmd/baz

  # This supports relative import paths as well.
  ko run ./cmd/baz

Flags:
  -B, --base-import-paths       Whether to use the base path without MD5 hash after KO_DOCKER_REPO.
      --disable-optimizations   Disable optimizations when building Go code. Useful when you want to interactively debug the created container.
  -h, --help                    help for run
      --insecure-registry       Whether to skip TLS verification on the registry
  -L, --local                   Whether to publish images to a local docker daemon vs. a registry.
  -P, --preserve-import-paths   Whether to preserve the full import path after KO_DOCKER_REPO.
  -t, --tags strings            Which tags to use for the produced image instead of the default 'latest' tag. (default [latest])
pod "ko-099ba5bcefdead87f92606265fb99ac0" deleted

[jonjohnsonjr]

This PR made debugging google/go-containerregistry#594 about 100x easier.

I was able to diagnose what was going on in basically 60 seconds with:

$ ko run ./cmd/gcrane/ -- cp -v ubuntu gcr.io/jonjohnson-test/ubuntu:copied