find docker name in a node.js application running inside docker container

Question

I have a node.js application running inside a docker container with base image node:16-alpine3.11. I want to get the name of the container on which it is running on.

ex:
docker ps:

CONTAINER ID     NAMES
xyz               node

test.js:
const c_name= //get container name

Answer 1

From outside the container

You can use the docker cli to do this. In the example we filter for ancestor bitnami/redis (in your case this would be node:16-alpine3.11)

$ docker container ls --filter "ancestor=bitnami/redis" --format "table {{.ID}}\t{{.Image}}\t{{.Names}}"

This returns the id, name and image of the container as a table. To retrieve the results as a json object, update the format flag like below:

docker container ls --filter "ancestor=bitnami/redis" --format 'json { "Id":"{{.ID}}", "Image": "{{.Image}}", "Names": "{{.Names}}" }'

See the handy cli reference docs provided by docker.

From Inside the Container

Pass the unix socket to the container and invoke a script to get the container name:

$ docker run -it -v "/var/run/docker.sock:/var/run/docker.sock" origami-duckling:latest

The Dockerfile for `origami-duckling looks like this:

FROM node:16-alpine3.11

WORKDIR /usr/app

RUN apk add curl jq
ENV DOCKER_HOST="unix:///run/docker.sock"

COPY get-container-name.sh /usr/app/get-container-name.sh
CMD /usr/app/get-name.sh

You would probably run the get-container-name before you use cmd to run the node app in your container.

The get-container-name.sh would look like this:

#!/usr/bin/env sh
export CONTAINER_NAME="$(curl -s --unix-socket /run/docker.sock http://docker/containers/$HOSTNAME/json | jq '.Name')"

echo $CONTAINER_NAME

Update: You can do this from within your node.js app if you need to:

I'm using got@11.8.3, got 12.x is pure ESM.

const got = require('got');
async function getHostName() {
  const metadata = await got(`http://unix:/var/run/docker.sock:/containers/${process.env.HOSTNAME}/json`).json();

  console.log('Container name', metadata.Name);
  return metadata.Name
}