Execute a Docker command inside a container using API calls with curl

docker-exec-api.sh

#!/bin/bash

# Docker API Exec proof of concept. Run a `date` command in a container with curl.

echo "Choose a container ID (or CTRL+C to exit)"
CONTAINER_ID_LIST=$(curl --unix-socket /var/run/docker.sock http://localhost/containers/json 2>/dev/null | jq -r .[].Id)

select CONTAINER_ID in $CONTAINER_ID_LIST; do

  # Create an exec instance and retain the ID that was returned.
  EXEC_ID=$(curl -s \
    --unix-socket /var/run/docker.sock \
    -X POST http://localhost/containers/${CONTAINER_ID}/exec \
    -H 'Content-Type: application/json' \
    --data '{ "Tty": true, "AttachStdin": false, "AttachStdout": true, "AttachStderr": true, "Cmd": [ "date", "--iso-8601=seconds" ] }' \
  | jq -r .Id)

  # Run the exec instance using the ID from the previous step.
  OUTPUT=$(curl -s \
    --unix-socket /var/run/docker.sock \
    -X POST http://localhost/exec/${EXEC_ID}/start \
    -H 'Content-Type: application/json' \
    --data '{ "Detach": false, "Tty": true }')

  # Display the command output.
  echo $OUTPUT
done