Allow to define changedif behavior for the shell resource

[olblak]

Opening for visibility

This pullrequest allows to have different success criteria for the shell resource.
It's an initial implementation based on this discussion
I am introduce three new success criteria which are:

• console/output - (current shell behavior)
• exitcode where we can specify which exit code to map to.
• file/checksum: that monitor file checksum to determine success

While the "console/output" introduce no change as it requires no configuration, we can use the following snippet to customize the exit code

sources
  echo:  
    name: Should be succeeding
    kind: shell
    spec:
      command: "echo 1.0.0"
      changedif:
        kind: exitcode
        spec:
          warning: 2
          failure: 1
          success: 0

conditions:
  success:
    disablesourceinput: true
    name: Test the condition succeed according success criteria despite command failing
    kind: shell
    spec:
      command: "false"
      changedif:
        kind: file/checksum
        spec:
          files:
            - e2e/updatecli.d/success.d/shell/checksum.yaml

Test

To test this pull request, you can run the following commands:

cp pkg/plugins/resources/shell/success/console/
go test 
pkg/plugins/resources/shell/success/exitcode/
go test
go build -o bin/updatecli .
./bin/updatecli diff --config e2e/updatecli.d/success.d/command.yaml
./bin/updatecli diff --config e2e/updatecli.d/success.d/shell

Additional Information

Tradeoff

I must admit that I am not a big fan of the word "outcome" another one that I could think of is "successcriteria" but I find it a bit long...

EDIT
I decided to go with success as I think it's pretty self explanatory
EDIT
Finally I leaning toward changedif

Potential improvement

As suggested in the discussion, I could imagine introducing more possible outcome rules such as file/exist when we need to monitor a lot of files

[olblak]

I think instead of outcome, 'success' would better capture the meaning

[olblak]

Damien suggestion would be to replace success to changedif

[dduportal]

Damien suggestion would be to replace success to changedif

changed_if to be precise :)

[olblak]

Damien suggestion would be to replace success to changedif

changed_if to be precise :)

After some experimentation with the jsonschema changed_if sounds fine so I'll proceed with it

[olblak]

For a reason that I ignore the following line

ChangedIf SpecChangedIf `yaml:"changed_if,omitempty" json:"changed_if,omitempty"`

Do no extract the changed_if but changedif, without the lowercase

[olblak]

But the json tag works correctly as the generated jsonschema has the property changed_if

[olblak]

Even thought I prefer the lowercase syntax, I can't figure out why the yaml tag is not correctly used. So I am just going to move forward without the underscore

[olblak]

Once the tests are passing here, I'll merge this pullrequest so I can finalize the npm autodiscovery one

[olblak]

Same remark than here until we release 0.44.0 after FOSDEM. I am open to change the name. Once release it will have to be deprecated