Refactor target resource to return more metadata

[olblak]

In an attempt to generate better report out of Updatecli execution, I am refactoring target resources with following compopents:

• Merge the functions Target() and TargetFromSCM

As the Updatecli project evolved, I realize that those two functions are useless code duplication, and introduce more complexity. Therefor I went over all plugin to simplify those two functions into one named Target()

The risk associated with this refactoring is that a target plugin working with scm repositories can be broken and this hard to fully tests in dev environment.

• Target function now return additional metadata during execution

I modify both the target function parameters and returned values. Target uses the new struct result.Target to store\

• Old value
• New Value
• execution result (success, attention, failure, skipped)
• message such as update yaml key "version" from x to y in file z

---

In very short

-       Target(source string, dryRun bool) (bool, error)
-       TargetFromSCM(source string, scm scm.ScmHandler, dryRun bool) (changed bool, files []string, message string, err error)
+       Target(source string, scm scm.ScmHandler, dryRun bool, targetResult *result.Target) (err error)

Where result.Target is:

// Target holds target execution result
type Target struct {
    // Name holds the target name
    Name string
    /*  
        Result holds the target result, accepted values must be one:
            * "SUCCESS"
            * "FAILURE"
            * "ATTENTION"
            * "SKIPPED"
    */
    Result string
    // OldInformation stores the old information detected by the target execution
    OldInformation string
    // NewInformation stores the new information updated by during the target execution
    NewInformation string
    // Description stores the target execution description
    Description string
    // Files holds the list of files modified by a target execution
    Files   []string
    Changed bool
}

---

Test

Considering that this pullrequest modifies all target plugin, we need as many tests as possible

Additional Information

Tradeoff

Not every target plugin has the ability to retrieve the old value before updating.
For example the shell plugin allows to run whatever scripts needed. For those situation, I decided to use the default value "unkown"

Potential improvement

We need similar refactoring for the condition and source plugins but I prefer to do as stage at the time considering the amount of files changed.

[olblak]

An example of possible report

=============================

REPORTS:


✔ Bump venom version:
	Source:
		✔ [latestVersion] Get latest Venom release (kind: githubrelease)
	Target:
		✔ [goWorkflow] Bump Venom version to v1.1.0
			=> all contents from 'file' and 'files' combined already up to date


Run Summary
===========
Pipeline(s) run:
  * Changed:	0
  * Failed:	0
  * Skipped:	0
  * Succeeded:	1
  * Total:	1

or

=============================

REPORTS:


✔ Bump epinio server version:
	Source:
		✔ [epinio] Get Latest epinio version (kind: gittag)
	Condition:
		✔ [dockerImage] Check that ghcr.io/epinio/epinio-server:v1.6.1 is published (kind: dockerimage)
		✔ [dockerImageRegistry] Check that 'ghcr.io' registry is used in Helm chart epinio (kind: yaml)
		✔ [dockerImageRepository] Check that container image repository 'epinio/epinio-server' is used in Helm chart epinio (kind: yaml)
	Target:
		✔ [epinioui] Update epinio version in chart epinio
			=> key "epinio-ui.epinioVersion" already set to "v1.6.1", from file "/tmp/updatecli/github/olblak/epinio-helm-chart/chart/epinio/values.yaml", 
		✔ [helm-charts] Update epinio version in chart epinio
			=> key "appVersion" already set to "v1.6.1", from file "/tmp/updatecli/github/olblak/epinio-helm-chart/chart/epinio/Chart.yaml", 


Run Summary
===========
Pipeline(s) run:
  * Changed:	0
  * Failed:	0
  * Skipped:	0
  * Succeeded:	1
  * Total:	1