feat: git Access, AccessMethod through BlobAccess

api/credentials/builtin/init.go

@@ -2,4 +2,5 @@ package builtin
 
 import (
 	_ "ocm.software/ocm/api/credentials/builtin/github"
+	_ "ocm.software/ocm/api/tech/git/identity"
 )

api/oci/cpi/support/base.go

@@ -31,18 +31,18 @@ func (a *artifactBase) IsReadOnly() bool {
 }
 
 func (a *artifactBase) IsIndex() bool {
-	d := a.state.GetState().(*artdesc.Artifact)
-	return d.IsIndex()
+	d, ok := a.state.GetState().(*artdesc.Artifact)
+	return ok && d.IsIndex()
 }
 
 func (a *artifactBase) IsManifest() bool {
-	d := a.state.GetState().(*artdesc.Artifact)
-	return d.IsManifest()
+	d, ok := a.state.GetState().(*artdesc.Artifact)
+	return ok && d.IsManifest()
 }
 
 func (a *artifactBase) IsValid() bool {
-	d := a.state.GetState().(*artdesc.Artifact)
-	return d.IsValid()
+	d, ok := a.state.GetState().(*artdesc.Artifact)
+	return ok && d.IsValid()
 }
 
 func (a *artifactBase) blob() (cpi.BlobAccess, error) {

api/oci/internal/uniform.go

@@ -31,7 +31,7 @@ type UniformRepositorySpec struct {
 	// Host is the hostname of an oci ref.
 	Host string `json:"host,omitempty"`
 	// Info is the file path used to host ctf component versions
-	Info string `json:"filePath,omitempty"`
+	Info string `json:"info,omitempty"`
 
 	// CreateIfMissing indicates whether a file based or dynamic repo should be created if it does not exist
 	CreateIfMissing bool `json:"createIfMissing,omitempty"`

api/ocm/elements/artifactaccess/gitaccess/options.go

@@ -0,0 +1,58 @@
+package gitaccess
+
+import (
+	"github.com/mandelsoft/goutils/optionutils"
+)
+
+type Option = optionutils.Option[*Options]
+
+type Options struct {
+	URL    string
+	Ref    string
+	Commit string
+}
+
+var _ Option = (*Options)(nil)
+
+func (o *Options) ApplyTo(opts *Options) {
+	if o.URL != "" {
+		opts.URL = o.URL
+	}
+}
+
+func (o *Options) Apply(opts ...Option) {
+	optionutils.ApplyOptions(o, opts...)
+}
+
+// //////////////////////////////////////////////////////////////////////////////
+// Local options
+
+type url string
+
+func (h url) ApplyTo(opts *Options) {
+	opts.URL = string(h)
+}
+
+func WithURL(h string) Option {
+	return url(h)
+}
+
+type ref string
+
+func (h ref) ApplyTo(opts *Options) {
+	opts.Ref = string(h)
+}
+
+func WithRef(h string) Option {
+	return ref(h)
+}
+
+type commitSpec string
+
+func (h commitSpec) ApplyTo(opts *Options) {
+	opts.Commit = string(h)
+}
+
+func WithCommit(c string) Option {
+	return commitSpec(c)
+}

api/ocm/elements/artifactaccess/gitaccess/resource.go

@@ -0,0 +1,25 @@
+package gitaccess
+
+import (
+	"github.com/mandelsoft/goutils/optionutils"
+
+	"ocm.software/ocm/api/ocm"
+	"ocm.software/ocm/api/ocm/compdesc"
+	"ocm.software/ocm/api/ocm/cpi"
+	"ocm.software/ocm/api/ocm/elements/artifactaccess/genericaccess"
+	access "ocm.software/ocm/api/ocm/extensions/accessmethods/git"
+	resourcetypes "ocm.software/ocm/api/ocm/extensions/artifacttypes"
+)
+
+const TYPE = resourcetypes.DIRECTORY_TREE
+
+func Access[M any, P compdesc.ArtifactMetaPointer[M]](ctx ocm.Context, meta P, opts ...Option) cpi.ArtifactAccess[M] {
+	eff := optionutils.EvalOptions(opts...)
+	if meta.GetType() == "" {
+		meta.SetType(TYPE)
+	}
+
+	spec := access.New(eff.URL, access.WithRef(eff.Ref), access.WithCommit(eff.Commit))
+	// is global access, must work, otherwise there is an error in the lib.
+	return genericaccess.MustAccess(ctx, meta, spec)
+}

api/ocm/extensions/accessmethods/git/README.md

@@ -0,0 +1,93 @@
+
+# Access Method `git` - Git Commit Access
+
+## Synopsis
+
+```yaml
+type: git/v1
+```
+
+Provided blobs use the following media type for: `application/x-tgz`
+
+The artifact content is provided as gnu-zipped tar archive
+
+### Description
+
+This method implements the access of the content of a git commit stored in a
+git repository.
+
+Supported specification version is `v1alpha1`
+
+### Specification Versions
+
+#### Version `v1alpha1`
+
+The type specific specification fields are:
+
+- **`repository`**  *string*
+
+  Repository URL with or without scheme.
+
+- **`ref`** (optional) *string*
+
+  Original ref used to get the commit from
+
+- **`commit`** *string*
+
+  The sha/id of the git commit
+
+### Go Bindings
+
+The go binding can be found [here](method.go)
+
+#### Example
+
+```go
+package main
+
+import (
+  "archive/tar"
+  "bytes"
+  "compress/gzip"
+  "fmt"
+  "io"
+
+  "ocm.software/ocm/api/ocm"
+  "ocm.software/ocm/api/ocm/cpi"
+  me "ocm.software/ocm/api/ocm/extensions/accessmethods/git"
+)
+
+func main() {
+  ctx := ocm.New()
+  accessSpec := me.New(
+    "https://github.com/octocat/Hello-World.git",
+    me.WithRef("refs/heads/master"),
+  )
+  method, err := accessSpec.AccessMethod(&cpi.DummyComponentVersionAccess{Context: ctx})
+  if err != nil {
+    panic(err)
+  }
+  content, err := method.GetContent()
+  if err != nil {
+    panic(err)
+  }
+  unzippedContent, err := gzip.NewReader(bytes.NewReader(content))
+
+  r := tar.NewReader(unzippedContent)
+
+  file, err := r.Next()
+  if err != nil {
+    panic(err)
+  }
+
+  if file.Name != "README.md" {
+    panic("Expected README.md")
+  }
+
+  data, err := io.ReadAll(r)
+  if err != nil {
+    panic(err)
+  }
+  fmt.Println(string(data))
+}
+```

api/ocm/extensions/accessmethods/git/cli.go

@@ -0,0 +1,43 @@
+package git
+
+import (
+	"ocm.software/ocm/api/ocm/extensions/accessmethods/options"
+	"ocm.software/ocm/api/utils/cobrautils/flagsets"
+)
+
+func ConfigHandler() flagsets.ConfigOptionTypeSetHandler {
+	return flagsets.NewConfigOptionTypeSetHandler(
+		Type, AddConfig,
+		options.RepositoryOption,
+		options.ReferenceOption,
+		options.CommitOption,
+	)
+}
+
+func AddConfig(opts flagsets.ConfigOptions, config flagsets.Config) error {
+	flagsets.AddFieldByOptionP(opts, options.RepositoryOption, config, "repository", "repo", "repoUrl", "repoURL")
+	flagsets.AddFieldByOptionP(opts, options.CommitOption, config, "commit")
+	flagsets.AddFieldByOptionP(opts, options.ReferenceOption, config, "ref")
+	return nil
+}
+
+var usage = `
+This method implements the access of the content of a git commit stored in a
+Git repository.
+`
+
+var formatV1 = `
+The type specific specification fields are:
+
+- **<code>repoUrl</code>**  *string*
+
+  Repository URL with or without scheme.
+
+- **<code>ref</code>** (optional) *string*
+
+  Original ref used to get the commit from
+
+- **<code>commit</code>** *string*
+
+  The sha/id of the git commit
+`