Draft release action to support monoreo

Modifies the draft handling code to support a monorepo where buildpack.toml is not at the root of the project. The default is still at the root of the project, but the path is configurable via environment variable.

Signed-off-by: Daniel Mikusa <[email protected]>

README.md

@@ -412,7 +412,9 @@ A Github token is strongly recommended. This is for fetching information from Gi
 
 The `package` and `version` entries are required. They are required to indiciate the specific buildpack that will be described.
 
-A mapper will add additional permutations of Github project URIs to try. For example, if you have an image URI of `gcr.io/foo/bar:1.2.3` but the Github project is at `github.com/org/foo-bar` then you can add a mapper of `|foo\/bar|org/foo-bar|` to have `compute-artifact-dependencies` try both. You can specify as many mappers as you want, with each mapper generating a new URI for `compute-artifact-dependencies` to try. It will stop when it hits the first URL that successfully pulls back the `buildpack.toml` file.
+A mapper will add additional permutations of Github project URIs to try. For example, if you have an image URI of `gcr.io/foo/bar:1.2.3` but the Github project is at `github.com/org/foo-bar` then you can add a mapper of `|foo\/bar|org/foo-bar|` to have `compute-artifact-dependencies` try both. You can specify as many mappers as you want, with each mapper generating a new URI for `compute-artifact-dependencies` to try. It will stop when it hits the first URL that successfully pulls back the `buildpack.toml` file.Mappers may use regexp capture groups and reference the captured value with `$<num>` (ex: `$1`, `$2`, etc) in the regular expression.
+
+The location of the `buildpack.toml` file in the Github project is assumed to be at `/buildpack.toml`. If you have a monorepo with multiple buildpacks, you may adjust the location by setting an environment variable in the format `BP_TOML_PATH_<org>_<repo>=actual/path` where `<org>` and `<repo>` are the organization and repo pulled out of the image URI. For example, `gcr.io/foo/bar:1.2.3`. The org is `foo` and the repo is `bar`. A leading `/` is not necessary, nor is `buildpack.toml` on the end. You may omit that to shorten the value and the action will automatically add `/buildpack.toml` to the end. For example, with an org of `vmware-tanzu` and a repo of `function-buildpacks-for-knative` the environment variable would be `BP_TOML_PATH_VMWARE_TANZU_FUNCTION_BUILDPACKS_FOR_KNATIVE='buildpacks/java/buildpack.toml`, which would be the same as `BP_TOML_PATH_VMWARE_TANZU_FUNCTION_BUILDPACKS_FOR_KNATIVE='buildpacks/java` since the trailing `buildpack.toml` is optional.
 
 The output is `artifact-reference-description`, which can be referenced by other jobs.
 
@@ -432,7 +434,9 @@ The `draft-release` action is used to augment release notes generated by the `re
 
 The `draft-release` action needs to be able to look up and remotely fetch buildpack metadata. It does this by obtaining the `buildpack.toml` file for any dependent buildpacks from Github. This requires mapping the image URI to the Github project URI, which is not always one-to-one. As such, the action supports mappers.
 
-A mapper will add additional permutations of Github project URIs to try. For example, if you have an image URI of `gcr.io/foo/bar:1.2.3` but the Github project is at `github.com/org/foo-bar` then you can add a mapper of `|foo\/bar|org/foo-bar|` to have `draft-release` try both. You can specify as many mappers as you want, with each mapper generating a new URI for `draft-release` to try. It will stop when it hits the first URL that successfully pulls back the `buildpack.toml` file.
+A mapper will add additional permutations of Github project URIs to try. For example, if you have an image URI of `gcr.io/foo/bar:1.2.3` but the Github project is at `github.com/org/foo-bar` then you can add a mapper of `|foo\/bar|org/foo-bar|` to have `draft-release` try both. You can specify as many mappers as you want, with each mapper generating a new URI for `draft-release` to try. It will stop when it hits the first URL that successfully pulls back the `buildpack.toml` file. Mappers may use regexp capture groups and reference the captured value with `$<num>` (ex: `$1`, `$2`, etc) in the regular expression.
+
+The location of the `buildpack.toml` file in the Github project is assumed to be at `/buildpack.toml`. If you have a monorepo with multiple buildpacks, you may adjust the location by setting an environment variable in the format `BP_TOML_PATH_<org>_<repo>=actual/path` where `<org>` and `<repo>` are the organization and repo pulled out of the image URI. For example, `gcr.io/foo/bar:1.2.3`. The org is `foo` and the repo is `bar`. A leading `/` is not necessary, nor is `buildpack.toml` on the end. You may omit that to shorten the value and the action will automatically add `/buildpack.toml` to the end. For example, with an org of `vmware-tanzu` and a repo of `function-buildpacks-for-knative` the environment variable would be `BP_TOML_PATH_VMWARE_TANZU_FUNCTION_BUILDPACKS_FOR_KNATIVE='buildpacks/java/buildpack.toml`, which would be the same as `BP_TOML_PATH_VMWARE_TANZU_FUNCTION_BUILDPACKS_FOR_KNATIVE='buildpacks/java` since the trailing `buildpack.toml` is optional.
 
 ```yaml
 uses: docker://ghcr.io/paketo-buildpacks/actions/draft-release:main

drafts/drafts.go

@@ -348,28 +348,36 @@ func (g GithubBuildpackLoader) LoadBuildpack(imgUri string) (Buildpack, error) {
 		org := parts[1]
 		repo := parts[2]
 		version := parts[3]
-		if regexp.MustCompile(`\d+\.\d+\.\d+`).MatchString(version) {
-			version = fmt.Sprintf("v%s", version)
-		}
 
-		tomlBytes, err := g.fetchTOMLFile(org, repo, version, "/buildpack.toml")
+		paths, err := g.mapBuildpackTOMLPath(org, repo)
 		if err != nil {
-			var apiErr *github.ErrorResponse
-			if errors.As(err, &apiErr) && apiErr.Response.StatusCode == 404 {
-				fmt.Println("skipping 404", apiErr)
-				continue
-			}
-			return Buildpack{}, fmt.Errorf("unable to fetch toml\n%w", err)
+			return Buildpack{}, fmt.Errorf("unable to map buildpack toml path\n%w", err)
 		}
 
-		if len(tomlBytes) > 0 {
-			bp, err := loadBuildpackTOML(tomlBytes)
+		if regexp.MustCompile(`^\d+\.\d+\.\d+$`).MatchString(version) {
+			version = fmt.Sprintf("v%s", version)
+		}
+
+		for _, path := range paths {
+			tomlBytes, err := g.fetchTOMLFile(org, repo, version, path)
 			if err != nil {
-				return Buildpack{}, fmt.Errorf("unable to load buildpack toml from image\n%w", err)
+				var apiErr *github.ErrorResponse
+				if errors.As(err, &apiErr) && apiErr.Response.StatusCode == 404 {
+					fmt.Println("skipping 404", apiErr)
+					continue
+				}
+				return Buildpack{}, fmt.Errorf("unable to fetch toml\n%w", err)
 			}
 
-			bp.Info.Version = parts[3]
-			return *bp, nil
+			if len(tomlBytes) > 0 {
+				bp, err := loadBuildpackTOML(tomlBytes)
+				if err != nil {
+					return Buildpack{}, fmt.Errorf("unable to load buildpack toml from image\n%w", err)
+				}
+
+				bp.Info.Version = parts[3]
+				return *bp, nil
+			}
 		}
 	}
 
@@ -442,8 +450,26 @@ func (g GithubBuildpackLoader) mapURIs(uri string) ([]string, error) {
 	return possibilities, nil
 }
 
+func (g GithubBuildpackLoader) mapBuildpackTOMLPath(org, repo string) ([]string, error) {
+	paths := []string{
+		"/buildpack.toml",
+	}
+
+	org = strings.ToUpper(strings.ReplaceAll(org, "-", "_"))
+	repo = strings.ToUpper(strings.ReplaceAll(repo, "-", "_"))
+
+	if p, found := os.LookupEnv(fmt.Sprintf("BP_TOML_PATH_%s_%s", org, repo)); found {
+		if !strings.HasSuffix(p, "/buildpack.toml") {
+			p = fmt.Sprintf("%s/buildpack.toml", p)
+		}
+		return []string{p}, nil
+	}
+
+	return paths, nil
+}
+
 func (g GithubBuildpackLoader) fetchTOMLFile(org, repo, version, path string) ([]byte, error) {
-	fmt.Println("Fetching from org:", org, "repo:", repo, "version:", version)
+	fmt.Println("Fetching from org:", org, "repo:", repo, "version:", version, "path:", path)
 	body, _, err := g.GithubClient.Repositories.DownloadContents(
 		context.Background(),
 		org,