Add plugin dependencies to releases file (#329)

In order to optimize lookups, we should add dependency information to
the plugin-releases.json file. This will allow us to avoid scanning
every .zip file to parse the buf.plugin.yaml.

cmd/release/main.go

@@ -220,10 +220,12 @@ func (c *command) calculateNewReleasePlugins(currentRelease *release.PluginRelea
 				URL:              downloadURL,
 				LastUpdated:      now,
 				Status:           status,
+				Dependencies:     pluginDependencies(plugin),
 			})
 		} else {
 			log.Printf("plugin %s:%s unchanged", pluginRelease.PluginName, pluginRelease.PluginVersion)
 			pluginRelease.Status = release.StatusExisting
+			pluginRelease.Dependencies = pluginDependencies(plugin)
 			existingPlugins = append(existingPlugins, pluginRelease)
 		}
 		return nil
@@ -242,6 +244,21 @@ func (c *command) calculateNewReleasePlugins(currentRelease *release.PluginRelea
 	return plugins, nil
 }
 
+func pluginDependencies(plugin *plugin.Plugin) []string {
+	if len(plugin.Deps) == 0 {
+		return nil
+	}
+	deps := make([]string, len(plugin.Deps))
+	for i, dep := range plugin.Deps {
+		if dep.Revision != 0 {
+			log.Fatalf("unsupported plugin dependency revision: %v", dep.Revision)
+		}
+		deps[i] = dep.Plugin
+	}
+	sort.Strings(deps)
+	return deps
+}
+
 func (c *command) loadMinisignPublicKeyFromFileOrPrivateKey(privateKey minisign.PrivateKey) (minisign.PublicKey, error) {
 	var publicKey minisign.PublicKey
 	if c.minisignPublicKey != "" {

internal/release/release.go

@@ -39,6 +39,7 @@ type PluginRelease struct {
 	URL              string    `json:"url"`            // URL to GitHub release zip file for the plugin - i.e. https://github.com/bufbuild/plugins/releases/download/20221121.1/bufbuild-connect-go-v1.1.0.zip
 	LastUpdated      time.Time `json:"last_updated"`
 	Status           Status    `json:"-"`
+	Dependencies     []string  `json:"dependencies,omitempty"` // direct dependencies on other plugins
 }
 
 // CalculateDigest will calculate the sha256 digest of the given file.