Redis Connector

Overview

The Redis connector is a data integration component provided by RobustMQ for bridging MQTT messages to Redis databases. It supports Single, Cluster, and Sentinel deployment modes, and uses command templates for flexible data writing, making it suitable for real-time caching, message queuing, session storage, and counter scenarios.

Configuration

Connector Configuration

The Redis connector uses RedisConnectorConfig for configuration:

pub struct RedisConnectorConfig {
    pub server: String,                       // Redis server address
    pub mode: RedisMode,                      // Deployment mode
    pub database: u8,                         // Database number
    pub username: Option<String>,             // Username
    pub password: Option<String>,             // Password
    pub sentinel_master_name: Option<String>, // Sentinel master name
    pub command_template: String,             // Command template
    pub tls_enabled: bool,                    // Enable TLS
    pub connect_timeout_ms: u64,              // Connection timeout (ms)
    pub pool_size: u32,                       // Connection pool size
    pub max_retries: u32,                     // Max retries
    pub retry_interval_ms: u64,              // Retry interval (ms)
}

pub enum RedisMode {
    Single,    // Single node
    Cluster,   // Cluster mode
    Sentinel,  // Sentinel mode
}

Configuration Parameters

Parameter	Type	Required	Default	Description	Example
server	String	Yes	-	Redis server address, max 1024 characters	127.0.0.1:6379
mode	String	No	single	Deployment mode: single, cluster, sentinel	single
database	Number	No	0	Database number, range: 0-15	0
username	String	No	-	Username (Redis 6.0+ ACL)	default
password	String	No	-	Password	password123
sentinel_master_name	String	No	-	Sentinel master name, required in sentinel mode	mymaster
command_template	String	Yes	-	Command template with ${key}, ${payload} placeholders, max 4096 characters	SET ${key} ${payload}
tls_enabled	Boolean	No	false	Enable TLS encryption	true
connect_timeout_ms	Number	No	5000	Connection timeout in milliseconds	10000
pool_size	Number	No	10	Connection pool size, range: 1-100	20
max_retries	Number	No	3	Maximum retry count	5
retry_interval_ms	Number	No	1000	Retry interval in milliseconds	2000

Command Templates

Command templates support the following placeholders:

Placeholder	Description
${key}	Message key
${payload}	Message content
${timestamp}	Message timestamp

Command Template Examples

SET ${key} ${payload}
LPUSH mqtt:messages ${payload}
HSET mqtt:data ${key} ${payload}
PUBLISH mqtt:channel ${payload}
SETEX ${key} 3600 ${payload}

Configuration Examples

JSON Configuration

Single Mode

{
  "server": "127.0.0.1:6379",
  "command_template": "LPUSH mqtt:messages ${payload}"
}

With Password

{
  "server": "127.0.0.1:6379",
  "password": "your_password",
  "database": 1,
  "command_template": "SET mqtt:${key} ${payload}",
  "pool_size": 20
}

Cluster Mode

{
  "server": "redis-1:6379,redis-2:6379,redis-3:6379",
  "mode": "cluster",
  "password": "cluster_password",
  "command_template": "SET mqtt:${key} ${payload}",
  "pool_size": 30,
  "connect_timeout_ms": 10000
}

Sentinel Mode

{
  "server": "sentinel-1:26379,sentinel-2:26379,sentinel-3:26379",
  "mode": "sentinel",
  "sentinel_master_name": "mymaster",
  "password": "sentinel_password",
  "command_template": "LPUSH mqtt:events ${payload}",
  "pool_size": 15
}

Creating a Redis Connector with robust-ctl

Basic Syntax

robust-ctl mqtt connector create \
  --connector-name <name> \
  --connector-type <type> \
  --config <config> \
  --topic-id <topic>

Examples

1. Basic Creation

robust-ctl mqtt connector create \
  --connector-name "redis_connector_01" \
  --connector-type "redis" \
  --config '{"server": "127.0.0.1:6379", "command_template": "LPUSH mqtt:messages ${payload}"}' \
  --topic-id "sensor/data"

2. Authenticated Redis

robust-ctl mqtt connector create \
  --connector-name "redis_auth" \
  --connector-type "redis" \
  --config '{"server": "127.0.0.1:6379", "password": "your_password", "database": 1, "command_template": "SET mqtt:${key} ${payload}", "pool_size": 20}' \
  --topic-id "device/status"

Managing Connectors

# List all connectors
robust-ctl mqtt connector list

# View specific connector
robust-ctl mqtt connector list --connector-name "redis_connector_01"

# Delete connector
robust-ctl mqtt connector delete --connector-name "redis_connector_01"

Performance Tips

1. Connection Pool

• Set pool_size based on concurrency requirements
• Increase pool size for high-throughput scenarios

2. Command Selection

• Use batch commands (e.g., LPUSH) to reduce network round trips
• Use SETEX or EXPIRE for data with TTL requirements
• Avoid blocking commands

3. Deployment Mode

• Single mode for development and testing
• Use Cluster or Sentinel mode in production
• Sentinel mode provides automatic failover

4. Security

• Enable TLS in production environments
• Use ACL (Redis 6.0+) for fine-grained access control
• Rotate passwords regularly

Troubleshooting

Common Issues

Connection Failure

• Check if Redis service is running
• Verify server address and port
• Check network and firewall settings

Authentication Failure

• Verify password is correct
• Check username and ACL configuration (Redis 6.0+)

Write Timeout

• Increase connect_timeout_ms
• Check Redis service load
• Consider increasing pool size

Sentinel Connection Issues

• Confirm sentinel_master_name is correct
• Check Sentinel nodes are running
• Verify connectivity to all Sentinel nodes

Summary

The Redis connector provides seamless integration with Redis databases, supporting Single, Cluster, and Sentinel deployment modes with flexible command templates for customizable data writing patterns.