XREADGROUP for consumer groups in Redis - Mini Project: Build & Apply

Using XREADGROUP to Read Messages from Redis Streams with Consumer Groups

📖 Scenario: You are building a simple message processing system using Redis streams. Multiple consumers will read messages from the same stream using a consumer group to share the workload.

🎯 Goal: Learn how to create a Redis stream, create a consumer group, and use XREADGROUP to read messages as a consumer from the group.

📋 What You'll Learn

Create a Redis stream called mystream with initial messages

Create a consumer group called mygroup on mystream

Use XREADGROUP to read messages as a consumer named consumer1

Acknowledge the messages after reading

💡 Why This Matters

🌍 Real World

Redis streams with consumer groups are used in real-time data processing systems, chat applications, and event sourcing to distribute workload among multiple consumers efficiently.

💼 Career

Understanding how to use XREADGROUP and consumer groups is important for backend developers and system architects working with Redis for scalable message processing.

1

Create the Redis stream mystream with initial messages

Use the Redis command XADD mystream * to add two messages with fields field1 and field2. Add the first message with values value1 and value2, and the second message with values value3 and value4.

Redis

# Add two messages to the Redis stream mystream
# Your code here

Need a hint?

Use XADD command twice to add two messages to mystream.

2

Create a consumer group mygroup on the stream mystream

Use the Redis command XGROUP CREATE mystream mygroup 0 to create a consumer group named mygroup starting from the beginning of the stream.

Redis

XADD mystream * field1 value1 field2 value2
XADD mystream * field1 value3 field2 value4
# Create consumer group mygroup on mystream
# Your code here

Need a hint?

Use XGROUP CREATE with the stream name, group name, and 0 to start from the first message.

3

Read messages from mystream as consumer consumer1 using XREADGROUP

Use the Redis command XREADGROUP GROUP mygroup consumer1 COUNT 2 STREAMS mystream > to read new messages from the stream mystream as the consumer consumer1 in the group mygroup. The > means to read only new messages not yet delivered to any consumer.

Redis

XADD mystream * field1 value1 field2 value2
XADD mystream * field1 value3 field2 value4
XGROUP CREATE mystream mygroup 0 MKSTREAM
# Read messages as consumer1 using XREADGROUP
# Your code here

Need a hint?

Use XREADGROUP GROUP mygroup consumer1 COUNT 2 STREAMS mystream > to read new messages for consumer1.

4

Acknowledge the messages after reading using XACK

Use the Redis command XACK mystream mygroup <message-id> to acknowledge each message you read. Replace <message-id> with the actual message IDs returned by XREADGROUP. For this exercise, acknowledge two messages with IDs 0-0 and 1-0.

Redis

XADD mystream * field1 value1 field2 value2
XADD mystream * field1 value3 field2 value4
XGROUP CREATE mystream mygroup 0 MKSTREAM
XREADGROUP GROUP mygroup consumer1 COUNT 2 STREAMS mystream >
# Acknowledge messages with IDs 0-0 and 1-0
# Your code here

Need a hint?

Use XACK command with the stream name, group name, and message IDs to acknowledge messages.