diff --git a/README.md b/README.md index 375755734b..0d44a0384f 100644 --- a/README.md +++ b/README.md @@ -53,6 +53,45 @@ $ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/app -w /usr/src/app node:4 node your-daemon-or-script.js ``` +## Verbosity + +By default Node.js Docker Image has NPM log verbosity set to `verbose` instead +of the default `warn`. This is because of the way Docker is isolated from the +host operating system and you are not guaranteed to be able to retrieve the +`npm-debug.log` file when something breaks. + +There are some scenarios where this creates too much output and you can reset +the verbosity of npm using the following techniques: + +### Dockerfile + +If you create your own `Dockerfile` which inherits from the `node` image you can +simply use `ENV` to override `NPM_CONFIG_LOGLEVEL`. + +``` +FROM node +ENV NPM_CONFIG_LOGLEVEL warn +... +``` + +### Docker Run + +If you run the node image using `docker runĖ™ you can use the `-e` flag to +override `NPM_CONFIG_LOGLEVEL`. + +``` +$ docker run -e NPM_CONFIG_LOGLEVEL=warn node ... +``` + +### NPM run + +If you are running npm commands you can use `--loglevel` to control the +verbosity of the output. + +``` +$ docker run node npm --loglevel=warn ... +``` + # Image Variants The `node` images come in many flavors, each designed for a specific use case.