gitrepo: Intro contentConfigChecksum & improvement

Introduce contentConfigChecksum in the GitRepository.Status to track the
configurations that affect the content of the artifact. It is used to
detect a change in the configuration that requires rebuilding the whole
artifact. This helps skip the reconciliation early when we find out that
the remote repository has not changed.

Moves fetching the included repositories in reconcileSource() to collect
enough information in reconcileSource() to be able to decide if the full
reconciliation can be skipped. This results in reconcileInclude() to
just copy artifact to the source build directory.

Introduce a gitCheckout() method to perform construction of all the git
checkout options and perform the checkout operation. This helps to
easily perform checkout multiple times when we need it in
reconcileSource(). When we check with the remote repository if there's
an update, and find out that there's no update, we check if any other
configurations that affect the source content has changed, like
includes, ignore rules, etc. If there's a change, we need to perform a
full checkout of the remote repository in order to fetch the complete
source. The git checkout no-op optimization is enabled in this method
based on the presence of an artifact in the storage.

The failure notification handler is modifed to handle the recovery of a
no-op reconcile failure and create a notification message accordingly
with the partial commit.

Signed-off-by: Sunny <darkowlzz@protonmail.com>

api/v1beta2/gitrepository_types.go

@@ -211,6 +211,18 @@ type GitRepositoryStatus struct {
 	// +optional
 	IncludedArtifacts []*Artifact `json:"includedArtifacts,omitempty"`
 
+	// ContentConfigChecksum is a checksum of all the configurations related to
+	// the content of the source artifact:
+	//  - .spec.ignore
+	//  - .spec.recurseSubmodules
+	//  - .spec.included and the checksum of the included artifacts
+	// observed in .status.observedGeneration version of the object. This can
+	// be used to determine if the content of the included repository has
+	// changed.
+	// It has the format of `<algo>:<checksum>`, for example: `sha256:<checksum>`.
+	// +optional
+	ContentConfigChecksum string `json:"contentConfigChecksum,omitempty"`
+
 	meta.ReconcileRequestStatus `json:",inline"`
 }
 

config/crd/bases/source.toolkit.fluxcd.io_gitrepositories.yaml

@@ -653,6 +653,15 @@ spec:
                   - type
                   type: object
                 type: array
+              contentConfigChecksum:
+                description: 'ContentConfigChecksum is a checksum of all the configurations
+                  related to the content of the source artifact:  - .spec.ignore  -
+                  .spec.recurseSubmodules  - .spec.included and the checksum of the
+                  included artifacts observed in .status.observedGeneration version
+                  of the object. This can be used to determine if the content of the
+                  included repository has changed. It has the format of `<algo>:<checksum>`,
+                  for example: `sha256:<checksum>`.'
+                type: string
               includedArtifacts:
                 description: IncludedArtifacts contains a list of the last successfully
                   included Artifacts as instructed by GitRepositorySpec.Include.