move manifest error field check out

main.go

@@ -63,7 +63,13 @@ func getUgoira(postId PostId, flags CliFlags) {
 		die("error while fetching manifest: %s", err)
 	}
 	// Now decode the JSON...
-	manifest := decodeUgoiraManifest(manifestJsonData)
+	manifest, err := decodeUgoiraManifest(manifestJsonData)
+	if err != nil {
+		die("%s", err)
+	}
+	if manifest.Error {
+		die("Manifest returned error: %s", manifest.Message)
+	}
 	if len(manifest.Body.OriginalSrc) == 0 {
 		die("Ugoira url is empty")
 	}
@@ -150,7 +156,11 @@ func ugoira2videoCmd(args []string, flags CliFlags) {
 		die("Could not read manifest: %s", err)
 	}
 
-	err = ugoira2video(decodeUgoiraManifest(manifestData), ugoiraFileName, flags.outputFileName, flags.ffmpegArgs)
+	manifest, err := decodeUgoiraManifest(manifestData)
+	if err != nil {
+		die("%s", err)
+	}
+	err = ugoira2video(manifest, ugoiraFileName, flags.outputFileName, flags.ffmpegArgs)
 	if err != nil {
 		die("Conversion failed: %s", err)
 	}

manifest.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 )
 
 type UgoiraManifestFrame struct {
@@ -22,13 +23,10 @@ type UgoiraManifest struct {
 	Body    UgoiraManifestBodyDesc `json:"body"`
 }
 
-func decodeUgoiraManifest(jsonData []byte) UgoiraManifest {
+func decodeUgoiraManifest(jsonData []byte) (UgoiraManifest, error) {
 	var manifest UgoiraManifest
 	if err := json.Unmarshal(jsonData, &manifest); err != nil {
-		die("Could not parse manifest JSON: %s", err)
+		return manifest, fmt.Errorf("Could not decode manifest JSON: %w", err)
 	}
-	if manifest.Error {
+	return manifest, nil
-		die("Manifest returned error: %s", manifest.Message)
-	}
-	return manifest
 }