Feat: support partial content for the resource "file"

[dduportal]

Fix #231 , depends on #321

This PR allows manipulating partial content of files.

• Source of kind file can now:

  • Read the whole content from a file or an URL (same as before)
  • Read only the content of the line (by specifying its number) from a file or an URL (breaking: removes the old behavior that was transfomring lines)
  • Read the content of matched string(s) (new behavior) when provided a regex pattern

• Conditions of kind file can now check that a file (or an URL) :

  • has its content matching the input source, or the specified content (same as before)
  • has the specified line matching the input source, or the specified content (new)
  • has the specified line not empty (new)
  • has its content, OR the specified line, matching the provided regex pattern (new)

• Targets of kind file can now update a file:

  • totally, .e.g its whole content from either the source input value or specified content (same as before)
  • partially for a line, e.g. only the specified line is changed to either the source input value or specified content (new)
  • partially for a match + replace regex pattern e.g. a search and replace is applied (new)

How to Test

• The file examples/updateCli.generic/file.yaml had been updated to be a "reference" of different cases
• Unit tests had been added to the plugin file to ensure that a lot of cases can be run in less than 1 seconds (not mentioning the ability to debug easily)

cd ./pkg/plugins/file
go test

• A real life test has been done with the file https://github.com/jenkins-infra/packer-images/blob/a3a5e4a7011c571a22ef6e274eefab334f70cc31/updatecli/updatecli.d/maven.yml that was changed to:

Click to show the code snippet

---
title: "Bump Maven version"
sources:
  getLatestMavenVersion:
    kind: githubRelease
    name: Get the latest Maven version
    spec:
      owner: "apache"
      repository: "maven"
      token: "{{ requiredEnv .github.token }}"
      username: "{{ .github.username }}"
      versionFilter:
        kind: latest
    transformers:
      - trimPrefix: "maven-"

conditions:
  checkIfReleaseIsAvailable:
    kind: shell
    disablesourceinput: true
    spec:
      command: curl --connect-timeout 5 --location --head --fail --silent --show-error https://archive.apache.org/dist/maven/maven-3/{{ source `getLatestMavenVersion` }}/binaries/apache-maven-{{ source `getLatestMavenVersion` }}-bin.tar.gz
  checkIfMavenVersionIsDefined:
    kind: file
    disablesourceinput: true
    spec:
      file: ".auto.pkrvars.hcl"
      matchPattern: 'maven_(.*)=.*'

targets:
  updateMavenVersion:
    name: Update the Maven version in the Packer default values
    sourceID: getLatestMavenVersion
    kind: file
    spec:
      file: ".auto.pkrvars.hcl"
      matchPattern: 'maven_(.*)=.*'
      replacePattern: 'maven_$1= "{{ source `getLatestMavenVersion` }}"'
    scm:
      github:
        user: "{{ .github.user }}"
        email: "{{ .github.email }}"
        owner: "{{ .github.owner }}"
        repository: "{{ .github.repository }}"
        token: "{{ requiredEnv .github.token }}"
        username: "{{ .github.username }}"
        branch: "{{ .github.branch }}"

Additional Details

• Related to the added Unit Test, the packages shell, scm and text are now providing a reusable Mock for some of their internals. This code is always stored within a file named mocks.go

[olblak]

Thanks, @dduportal for the effort in this pull request, excepted minor suggestion, it seems ready to me. I let you rebase and then merge the PR once you considered my comments.

[olblak]

I think it would be better to run all validation, collect every error in a list of errors and then exit an error if there is at least one error. The purpose is to detect every potential configuration issue.

[dduportal]

It had been applied as we discussed: The method has a list of error strings, and they are returned one time for all.

[dduportal]

Doc PR (wip): updatecli/website#161