semconvgen: add only flag to proccess only a specified type

Signed-off-by: Benedikt Bongartz <bongartz@klimlive.de>

.chloggen/semconv_add_only_flag.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. crosslink)
+component: semconvgen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: add only flag to proccess only a specified type
+
+# One or more tracking issues related to the change
+issues: [216]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

semconvgen/generator.go

@@ -41,6 +41,7 @@ func main() {
 
 	cfg := config{}
 	flag.StringVarP(&cfg.inputPath, "input", "i", "", "Path to semantic convention definition YAML. Should be a directory in the specification git repository.")
+	flag.StringVarP(&cfg.onlyType, "only", "", "", "Process only semantic conventions of the specified type. {span,resource,event,metric,units,scope}")
 	flag.StringVarP(&cfg.specVersion, "specver", "s", "", "Version of semantic convention to generate. Must be an existing version tag in the specification git repository.")
 	flag.StringVarP(&cfg.outputPath, "output", "o", "", "Path to output target. Must be either an absolute path or relative to the repository root. If unspecified will output to a sub-directory with the name matching the version number specified via --specver flag.")
 	flag.StringVarP(&cfg.containerImage, "container", "c", "otel/semconvgen", "Container image ID")
@@ -78,6 +79,7 @@ type config struct {
 	outputFilename     string
 	templateFilename   string
 	templateParameters string
+	onlyType           string
 	containerImage     string
 	specVersion        string
 }
@@ -165,10 +167,17 @@ func render(cfg config) error {
 		"-v", fmt.Sprintf("%s:/data", tmpDir),
 		cfg.containerImage,
 		"--yaml-root", path.Join("/data/input/semantic_conventions/", path.Base(cfg.inputPath)),
+		"--only", cfg.onlyType,
+	}
+	if cfg.onlyType != "" {
+		args = append(args, "--only", cfg.onlyType)
+	}
+
+	args = append(args,
 		"code",
 		"--template", path.Join("/data", path.Base(cfg.templateFilename)),
 		"--output", path.Join("/data/output", path.Base(cfg.outputFilename)),
-	}
+	)
 	if cfg.templateParameters != "" {
 		args = append(args, "--parameters", cfg.templateParameters)
 	}