worker: introduce JobImplementation interface

Introduce JobImplementation and turn the current RunJob() into
OSBuildJobImpl. Make main() select a job impl based on job type.

This is in preparation to add additional impls.

cmd/osbuild-worker/jobimpl-osbuild.go

@@ -23,6 +23,11 @@ import (
 	"github.com/osbuild/osbuild-composer/internal/worker"
 )
 
+type OSBuildJobImpl struct {
+	Store       string
+	KojiServers map[string]koji.GSSAPICredentials
+}
+
 func packageMetadataToSignature(pkg osbuild.RPMPackageMetadata) *string {
 	if pkg.SigGPG != "" {
 		return &pkg.SigGPG
@@ -56,7 +61,7 @@ func osbuildStagesToRPMs(stages []osbuild.StageResult) []koji.RPM {
 	return rpms
 }
 
-func RunJob(job worker.Job, store string, kojiServers map[string]koji.GSSAPICredentials) error {
+func (impl *OSBuildJobImpl) Run(job worker.Job) error {
 	outputDirectory, err := ioutil.TempDir("/var/tmp", "osbuild-worker-*")
 	if err != nil {
 		return fmt.Errorf("error creating temporary output directory: %v", err)
@@ -76,7 +81,7 @@ func RunJob(job worker.Job, store string, kojiServers map[string]koji.GSSAPICred
 
 	start_time := time.Now()
 
-	osbuildOutput, err := RunOSBuild(args.Manifest, store, outputDirectory, os.Stderr)
+	osbuildOutput, err := RunOSBuild(args.Manifest, impl.Store, outputDirectory, os.Stderr)
 	if err != nil {
 		return err
 	}
@@ -194,7 +199,7 @@ func RunJob(job worker.Job, store string, kojiServers map[string]koji.GSSAPICred
 			}
 
 			kojiServer, _ := url.Parse(options.Server)
-			creds, exists := kojiServers[kojiServer.Hostname()]
+			creds, exists := impl.KojiServers[kojiServer.Hostname()]
 			if !exists {
 				r = append(r, fmt.Errorf("Koji server has not been configured: %s", kojiServer.Hostname()))
 				continue

cmd/osbuild-worker/main.go

@@ -27,6 +27,11 @@ type connectionConfig struct {
 	ClientCertFile string
 }
 
+// Represents the implementation of a job type as defined by the worker API.
+type JobImplementation interface {
+	Run(job worker.Job) error
+}
+
 func createTLSConfig(config *connectionConfig) (*tls.Config, error) {
 	caCertPEM, err := ioutil.ReadFile(config.CACertFile)
 	if err != nil {
@@ -144,19 +149,37 @@ func main() {
 		}
 	}
 
+	jobImpls := map[string]JobImplementation{
+		"osbuild": &OSBuildJobImpl{
+			Store:       store,
+			KojiServers: kojiServers,
+		},
+	}
+
+	acceptedJobTypes := []string{}
+	for jt := range jobImpls {
+		acceptedJobTypes = append(acceptedJobTypes, jt)
+	}
+
 	for {
 		fmt.Println("Waiting for a new job...")
-		job, err := client.RequestJob([]string{"osbuild"})
+		job, err := client.RequestJob(acceptedJobTypes)
 		if err != nil {
 			log.Fatal(err)
 		}
 
+		impl, exists := jobImpls[job.Type()]
+		if !exists {
+			log.Printf("Ignoring job with unknown type %s", job.Type())
+			continue
+		}
+
 		fmt.Printf("Running '%s' job %v\n", job.Type(), job.Id())
 
 		ctx, cancelWatcher := context.WithCancel(context.Background())
 		go WatchJob(ctx, job)
 
-		err = RunJob(job, store, kojiServers)
+		err = impl.Run(job)
 		cancelWatcher()
 		if err != nil {
 			log.Printf("Job %s failed: %v", job.Id(), err)