osbuild-composer/config: new option: ignore_missing_repos

osbuild/images added an error type that's returned when the reporegistry
loader doesn't find any repository configurations to load [1].  This
lets callers decide whether to stop or continue execution based on
whether repository configurations are required.

A new top-level configuration option is added for osbuild-composer that
makes it possible to start the service without having static rpm
repositories configured.  This is useful in certain (SaaS) modes where
build requests specify their own repository configurations.

cmd/osbuild-composer/composer.go

@@ -78,16 +78,30 @@ func NewComposer(config *ComposerConfigFile, stateDir, cacheDir string) (*Compos
 	}
 
 	repoConfigs, err := reporegistry.LoadAllRepositories(repositoryConfigs)
-	if err != nil {
-		return nil, fmt.Errorf("error loading repository definitions: %v", err)
+	switch err.(type) {
+	case *reporegistry.NoReposLoadedError:
+		if !c.config.IgnoreMissingRepos {
+			return nil, fmt.Errorf("error loading repository definitions: %w", err)
+		}
+		// running without repositories is allowed: log message and continue
+		logrus.Info(err.Error())
+		logrus.Info("ignore_missing_repos enabled: continuing")
+	case nil:
+		c.repos = reporegistry.NewFromDistrosRepoConfigs(repoConfigs)
+	default:
+		return nil, fmt.Errorf("error loading repository definitions: %w", err)
 	}
-	c.repos = reporegistry.NewFromDistrosRepoConfigs(repoConfigs)
 
 	c.solver = dnfjson.NewBaseSolver(path.Join(c.cacheDir, "rpmmd"))
 	c.solver.SetDNFJSONPath(c.config.DNFJson)
 
-	// Clean up the cache, removes unknown distros and files
-	c.solver.CleanupOldCacheDirs(c.repos.ListDistros())
+	// Clean up the cache, removes unknown distros and files.
+	// If no repos are configured, the cache is cleared out completely.
+	var repoDistros []string
+	if c.repos != nil {
+		repoDistros = c.repos.ListDistros()
+	}
+	c.solver.CleanupOldCacheDirs(repoDistros)
 
 	var jobs jobqueue.JobQueue
 	if config.Worker.PGDatabase != "" {

cmd/osbuild-composer/config.go

@@ -12,18 +12,19 @@ import (
 )
 
 type ComposerConfigFile struct {
-	Koji              KojiAPIConfig     `toml:"koji"`
-	Worker            WorkerAPIConfig   `toml:"worker"`
-	WeldrAPI          WeldrAPIConfig    `toml:"weldr_api"`
-	DistroAliases     map[string]string `toml:"distro_aliases" env:"DISTRO_ALIASES"`
-	LogLevel          string            `toml:"log_level"`
-	LogFormat         string            `toml:"log_format"`
-	DNFJson           string            `toml:"dnf-json"`
-	SplunkHost        string            `env:"SPLUNK_HEC_HOST"`
-	SplunkPort        string            `env:"SPLUNK_HEC_PORT"`
-	SplunkToken       string            `env:"SPLUNK_HEC_TOKEN"`
-	GlitchTipDSN      string            `env:"GLITCHTIP_DSN"`
-	DeploymentChannel string            `env:"CHANNEL"`
+	Koji               KojiAPIConfig     `toml:"koji"`
+	Worker             WorkerAPIConfig   `toml:"worker"`
+	WeldrAPI           WeldrAPIConfig    `toml:"weldr_api"`
+	DistroAliases      map[string]string `toml:"distro_aliases" env:"DISTRO_ALIASES"`
+	LogLevel           string            `toml:"log_level"`
+	LogFormat          string            `toml:"log_format"`
+	DNFJson            string            `toml:"dnf-json"`
+	IgnoreMissingRepos bool              `toml:"ignore_missing_repos"`
+	SplunkHost         string            `env:"SPLUNK_HEC_HOST"`
+	SplunkPort         string            `env:"SPLUNK_HEC_PORT"`
+	SplunkToken        string            `env:"SPLUNK_HEC_TOKEN"`
+	GlitchTipDSN       string            `env:"GLITCHTIP_DSN"`
+	DeploymentChannel  string            `env:"CHANNEL"`
 }
 
 type KojiAPIConfig struct {
@@ -129,9 +130,10 @@ func GetDefaultConfig() *ComposerConfigFile {
 			"rhel-9":  "rhel-9.5",
 			"rhel-10": "rhel-10.0",
 		},
-		LogLevel:  "info",
-		LogFormat: "journal",
-		DNFJson:   "/usr/libexec/osbuild-depsolve-dnf",
+		LogLevel:           "info",
+		LogFormat:          "journal",
+		DNFJson:            "/usr/libexec/osbuild-depsolve-dnf",
+		IgnoreMissingRepos: false,
 	}
 }