Allow to configure kamel CLI with env vars and configuration files

[lburgazzoli]

Fixes #1108

You can now configure default values for any kamel command in a file named .kamel/config.yaml in the current working directory or in the user home like:

kamel:
  install:
    kits:
      - js
      - yaml
    maven-repositories:
      - http://repository.apache.org/snapshots@id=apache.snapshots@snapshots@noreleases
      - http://oss.sonatype.org/content/repositories/snapshots@id=oss.snapshots@snapshots@noreleases

Environment variables can be used to so the configuration below can be replaced by:

KAMEL_INSTALL_KITS="js,yaml"
KAMEL_INSTALL_MAVEN_REPOSITORIES="http://repository.apache.org/snapshots@id=apache.snapshots@snapshots@noreleases,http://oss.sonatype.org/content/repositories/snapshots@id=oss.snapshots@snapshots@noreleases"

You can of course mix command flags, environment variables and configuration files (in the given order of priority).

Note that inside a configuration file or environment variables, multi value flags are expressed through the plural for of the flag, as example:

kamel install --kit=js --kit=java

is equivalent to

KAMEL_INSTALL_KITS="js,java" kamel install

Release Note

Default values for the kamel CLI can now be configured through a configuration file and/or environment variables.

[lburgazzoli]

I still need to work on proper unit test but that would require a major refactor of how we create commands so for the moment it would be nice if anyone can test this PR an report any misbehaviour.

[valdar]

@lburgazzoli Ah! actually I have that refactor almost done in some stashed commit locally... based on a years-old camel-k ...

[jamesnetherton]

Question about:

multi value flags are expressed through the plural for of the flag

Does that apply to everything? E.g if I want to apply a set of environment variables to my integration via the --env flag of kamel run.

The singular version works:

KAMEL_RUN_ENV="FOO=BAR,CHEESE=WINE" kamel run examples/Sample.java

The plural version does not:

KAMEL_RUN_ENVS="FOO=BAR,CHEESE=WINE" kamel run examples/Sample.java

That's seems a bug as it is supposed to be working. It may be an issue as the plural form is computed and maybe not working for that, will have a look. In any case the singular version is always there but does not look very nice for multi val flags

[nicolaferraro]

Question about:

multi value flags are expressed through the plural for of the flag

Does that apply to everything? E.g if I want to apply a set of environment variables to my integration via the --env flag of kamel run.

The singular version works:

KAMEL_RUN_ENV="FOO=BAR,CHEESE=WINE" kamel run examples/Sample.java

The plural version does not:

KAMEL_RUN_ENVS="FOO=BAR,CHEESE=WINE" kamel run examples/Sample.java

That's seems a bug as it is supposed to be working. It may be an issue as the plural form is computed and maybe not working for that, will have a look. In any case the singular version is always there but does not look very nice for multi val flags

A different thing (nice to have?) would be to have a named config for each runnable integration, like:

kamel:
  install:
    kits:
      - js
      - yaml
  run:
    hello.groovy:
      dependencies:
      - "camel:jackson"

[lburgazzoli]

A different thing (nice to have?) would be to have a named config for each runnable integration, like:

kamel:
  install:
    kits:
      - js
      - yaml
  run:
    hello.groovy:
      dependencies:
      - "camel:jackson"

that would be much more complex as you'd need to determine first the name of the integration which is itself something you can grab from env or file.

maybe I can add en env var to control a sort of prefix/profile

[lburgazzoli]

@jamesnetherton your issues should be fixed now
@nicolaferraro you can not change the name of the configuration file with the env var KAMEL_CONFIG_NAME, this is not a full profile thing but helps a little

[valdar]

finally LGTM!