fix: set DOCKER_CONFIG dynamically

Author: johnstcn

envbuilder.go

@@ -1490,9 +1490,15 @@ func initDockerConfigJSON(logf log.Func, magicDir constants.MagicDir, dockerConf
 		return noop, fmt.Errorf("write docker config: %w", err)
 	}
 	logf(log.LevelInfo, "Wrote Docker config JSON to %s", cfgPath)
+	oldDockerConfig := os.Getenv("DOCKER_CONFIG")
+	os.Setenv("DOCKER_CONFIG", magicDir.String())
+	logf(log.LevelInfo, "Set DOCKER_CONFIG to %s", magicDir.String())
 	cleanup := func() error {
 		var cleanupErr error
 		cleanupOnce.Do(func() {
+			// Restore the old DOCKER_CONFIG value.
+			os.Setenv("DOCKER_CONFIG", oldDockerConfig)
+			logf(log.LevelInfo, "Restored DOCKER_CONFIG to %s", oldDockerConfig)
 			// Remove the Docker config secret file!
 			if cleanupErr = os.Remove(cfgPath); err != nil {
 				if !errors.Is(err, fs.ErrNotExist) {

scripts/Dockerfile

@@ -4,7 +4,5 @@ ARG TARGETARCH
 COPY envbuilder-${TARGETARCH} /.envbuilder/bin/envbuilder
 
 ENV KANIKO_DIR /.envbuilder
-# Kaniko looks for the Docker config at $DOCKER_CONFIG/config.json
-ENV DOCKER_CONFIG /.envbuilder
 
 ENTRYPOINT ["/.envbuilder/bin/envbuilder"]