osbuild2: add support for reading stage metadata

Metadata from stages in the output from osbuild in the v2 schema are
stored at the top level of the result structure.

Adding the same Metadata types from v1:
- org.osbuild.rpm stage
- org.osbuild.ostree.commit stage
- Raw metadata (for every other stage type)

internal/osbuild2/ostree_commit_stage.go

@@ -39,3 +39,23 @@ func NewOSTreeCommitStage(options *OSTreeCommitStageOptions, inputs *OSTreeCommi
 		Inputs:  inputs,
 	}
 }
+
+type OSTreeCommitStageMetadata struct {
+	Compose OSTreeCommitStageMetadataCompose `json:"compose"`
+}
+
+type OSTreeCommitStageMetadataCompose struct {
+	Ref                       string `json:"ref"`
+	OSTreeNMetadataTotal      int    `json:"ostree-n-metadata-total"`
+	OSTreeNMetadataWritten    int    `json:"ostree-n-metadata-written"`
+	OSTreeNContentTotal       int    `json:"ostree-n-content-total"`
+	OSTreeNContentWritten     int    `json:"ostree-n-content-written"`
+	OSTreeNCacheHits          int    `json:"ostree-n-cache-hits"`
+	OSTreeContentBytesWritten int    `json:"ostree-content-bytes-written"`
+	OSTreeCommit              string `json:"ostree-commit"`
+	OSTreeContentChecksum     string `json:"ostree-content-checksum"`
+	OSTreeTimestamp           string `json:"ostree-timestamp"`
+	RPMOSTreeInputHash        string `json:"rpm-ostree-inputhash"`
+}
+
+func (OSTreeCommitStageMetadata) isStageMetadata() {}

internal/osbuild2/result.go

@@ -14,6 +14,18 @@ type StageResult struct {
 	Error   string `json:"string,omitempty"`
 }
 
+type PipelineMetadata map[string]StageMetadata
+
+type StageMetadata interface {
+	isStageMetadata()
+}
+
+// RawStageMetadata is used to store the metadata from a stage that doesn't
+// define its own structure
+type RawStageMetadata json.RawMessage
+
+func (RawStageMetadata) isStageMetadata() {}
+
 // UnmarshalJSON decodes json-encoded StageResult.
 //
 // This method is here only as a workaround for the default value of the
@@ -40,9 +52,38 @@ func (sr *StageResult) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
-type Result struct {
-	Type    string                    `json:"type"`
-	Success bool                      `json:"success"`
-	Error   json.RawMessage           `json:"error"`
-	Log     map[string]PipelineResult `json:"log"`
+func (md *PipelineMetadata) UnmarshalJSON(data []byte) error {
+	var rawPipelineMetadata map[string]json.RawMessage
+	if err := json.Unmarshal(data, &rawPipelineMetadata); err != nil {
+		return err
+	}
+	pmd := make(map[string]StageMetadata)
+	var metadata StageMetadata
+	for name, rawStageData := range rawPipelineMetadata {
+		switch name {
+		case "org.osbuild.rpm":
+			metadata = new(RPMStageMetadata)
+			if err := json.Unmarshal(rawStageData, metadata); err != nil {
+				return err
+			}
+		case "org.osbuild.ostree.commit":
+			metadata = new(OSTreeCommitStageMetadata)
+			if err := json.Unmarshal(rawStageData, metadata); err != nil {
+				return err
+			}
+		default:
+			metadata = RawStageMetadata(rawStageData)
+		}
+		pmd[name] = metadata
+	}
+	*md = pmd
+	return nil
+}
+
+type Result struct {
+	Type     string                      `json:"type"`
+	Success  bool                        `json:"success"`
+	Error    json.RawMessage             `json:"error"`
+	Log      map[string]PipelineResult   `json:"log"`
+	Metadata map[string]PipelineMetadata `json:"metadata"`
 }

internal/osbuild2/rpm_stage.go

@@ -51,3 +51,22 @@ func NewRPMStage(options *RPMStageOptions, inputs *RPMStageInputs) *Stage {
 		Options: options,
 	}
 }
+
+// RPMStageMetadata gives the set of packages installed by the RPM stage
+type RPMStageMetadata struct {
+	Packages []RPMPackageMetadata `json:"packages"`
+}
+
+// RPMPackageMetadata contains the metadata extracted from one RPM header
+type RPMPackageMetadata struct {
+	Name    string  `json:"name"`
+	Version string  `json:"version"`
+	Release string  `json:"release"`
+	Epoch   *string `json:"epoch"`
+	Arch    string  `json:"arch"`
+	SigMD5  string  `json:"sigmd5"`
+	SigPGP  string  `json:"sigpgp"`
+	SigGPG  string  `json:"siggpg"`
+}
+
+func (RPMStageMetadata) isStageMetadata() {}