feat(job): support templ command

cmd/relspec/job.go

@@ -16,7 +16,9 @@ import (
 	"git.warky.dev/wdevs/relspecgo/pkg/models"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers"
 	"git.warky.dev/wdevs/relspecgo/pkg/readers/sqldir"
+	"git.warky.dev/wdevs/relspecgo/pkg/writers"
 	wpgsql "git.warky.dev/wdevs/relspecgo/pkg/writers/pgsql"
+	wtemplate "git.warky.dev/wdevs/relspecgo/pkg/writers/template"
 )
 
 var (
@@ -54,7 +56,7 @@ inputs, output and options:
       logfile: .relspec/log/build-schema.log
 
 Rules and guarantees:
-  - command is a closed allow-list (convert, merge, scripts-list). Arbitrary
+  - command is a closed allow-list (convert, merge, scripts-list, templ). Arbitrary
     shell strings are never executed.
   - Every path is relative to the directory holding the job file and may not
     escape it. Absolute and home-relative paths are rejected.
@@ -215,6 +217,7 @@ type resolvedJob struct {
 	outputConn    string // resolved connection string (secret)
 	outputConnEnv string
 	logPath       string
+	templatePath  string
 	secrets       []string // resolved secret values to redact from logs
 }
 
@@ -236,6 +239,17 @@ func preflightJob(j *jobs.Job) (*resolvedJob, error) {
 		}
 		rj.logPath = p
 	}
+	if j.Template != "" {
+		p, err := jobs.SafeJoin(root, j.Template)
+		if err != nil {
+			return nil, fmt.Errorf("template: %w", err)
+		}
+		info, err := os.Stat(p)
+		if err != nil || info.IsDir() {
+			return nil, fmt.Errorf("template %q: not found or is a directory", j.Template)
+		}
+		rj.templatePath = p
+	}
 
 	for i, in := range j.Inputs {
 		ri := resolvedInput{format: strings.ToLower(in.Format)}
@@ -348,6 +362,8 @@ func executeResolvedJob(rj *resolvedJob) (err error) {
 		err = runMergeJob(rj, lg)
 	case jobs.CommandScriptsList:
 		err = runScriptsListJob(rj, lg)
+	case jobs.CommandTempl:
+		err = runTemplJob(rj, lg)
 	default:
 		err = fmt.Errorf("unsupported command %q", rj.job.Command)
 	}
@@ -359,6 +375,50 @@ func executeResolvedJob(rj *resolvedJob) (err error) {
 	return err
 }
 
+func runTemplJob(rj *resolvedJob, lg *jobLogger) error {
+	db, err := readJobInputs(rj, lg)
+	if err != nil {
+		return err
+	}
+	if schema := rj.job.Options.Schema; schema != "" {
+		found := false
+		for _, s := range db.Schemas {
+			if s.Name == schema {
+				db.Schemas = []*models.Schema{s}
+				found = true
+				break
+			}
+		}
+		if !found {
+			return fmt.Errorf("schema not found: %s", schema)
+		}
+	}
+	mode := rj.job.Mode
+	if mode == "" {
+		mode = "database"
+	}
+	pattern := rj.job.FilenamePattern
+	if pattern == "" {
+		pattern = "{{.Name}}.txt"
+	}
+	writer, err := wtemplate.NewWriter(&writers.WriterOptions{
+		OutputPath: rj.outputPath,
+		Metadata: map[string]interface{}{
+			"template_path":    rj.templatePath,
+			"mode":             mode,
+			"filename_pattern": pattern,
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("create template writer: %w", err)
+	}
+	lg.logf("applying template: %s (mode %s)", rj.templatePath, mode)
+	if err := writer.WriteDatabase(db); err != nil {
+		return fmt.Errorf("execute template: %w", err)
+	}
+	return nil
+}
+
 func runConvertJob(rj *resolvedJob, lg *jobLogger) error {
 	db, err := readJobInputs(rj, lg)
 	if err != nil {