Docker events monitoring - Mini Project: Build & Apply

Docker Events Monitoring

📖 Scenario: You are a system administrator who wants to monitor Docker container events in real-time. This helps you track when containers start, stop, or change state, which is important for managing your applications.

🎯 Goal: Build a simple script that listens to Docker events and filters them to show only container start and stop events.

📋 What You'll Learn

Use the docker events command to listen to Docker events.

Filter events to show only start and stop container events.

Display the event type and container ID for each event.

💡 Why This Matters

🌍 Real World

Monitoring Docker events helps system administrators track container lifecycle changes and troubleshoot issues quickly.

💼 Career

Understanding Docker event monitoring is useful for DevOps engineers and system administrators managing containerized applications.

1

Set up Docker event listening command

Write a command to listen to Docker events using docker events and save it in a variable called event_command.

Docker

# Create a variable called event_command with the value 'docker events'
# Your code here

Need a hint?

Use a string variable to store the command docker events.

2

Add filters for start and stop events

Add a variable called filters that contains the filter options to show only start and stop events for containers. Use the Docker CLI filter syntax: --filter 'event=start' --filter 'event=stop'.

Docker

event_command = 'docker events'
# Create a variable called filters with the value "--filter 'event=start' --filter 'event=stop'"
# Your code here

Need a hint?

Filters must be a string with two filter options for start and stop events.

3

Combine command and filters

Create a variable called full_command that combines event_command and filters with a space between them.

Docker

event_command = 'docker events'
filters = "--filter 'event=start' --filter 'event=stop'"
# Combine event_command and filters into full_command
# Your code here

Need a hint?

Use string concatenation with a space to combine the command and filters.

4

Run the command and display events

Write code to run full_command using subprocess.Popen to capture output line by line. For each line, print only the event type and container ID. Use print(event_type, container_id). Assume event lines contain the words start or stop and the container ID is the word after container.

Docker

import subprocess

event_command = 'docker events'
filters = "--filter 'event=start' --filter 'event=stop'"
full_command = event_command + ' ' + filters

# Run full_command and print event type and container ID for each event line
# Your code here

Need a hint?

Use subprocess.Popen with shell=True and text=True to read output line by line.

Split each line and find the event type and container ID by checking words.