Redis Bridge Plugin

Redis Bridge Plugin is a bridge plugin for MQTT message and Redis integration. This plugin supports real-time storage of MQTT messages to Redis SortedSet, can configure multiple Redis instances, supports database selection and password authentication. Messages are stored using timestamps as scores, supporting custom message encoding formats.

Main Features

• Support configuration of multiple Redis instances
• Support Redis database selection
• Support Redis password authentication
• Support custom message encoding formats
• Use timestamp as SortedSet score
• Real-time message storage

Configuration Instructions

Plugin uses YAML format for configuration, main configuration parameters are as follows:

redis:
  - address: "localhost:6379"    # Redis server address and port
    database: 0                  # Redis database number (0-15)
    password: "your_password"    # Redis access password (optional)
    encode: "STRING"            # Message encoding format (default: STRING)
  - address: "redis2:6379"      # Can configure multiple Redis instances
    database: 1
    password: "password2"

Configuration Parameter Description

• address: Redis server address, format is “host:port”
• database: Redis database number, range 0-15
• password: Redis server access password, can be omitted if no password is set
• encode: Message encoding format, defaults to “STRING”, supports multiple encoding methods

Usage Scenarios

1. MQTT message persistent storage
2. Message history query service
3. Message data analysis and statistics
4. Real-time data monitoring system

Notes

1. Ensure Redis server address is configured correctly and accessible
2. Avoid duplicate configuration of the same Redis address
3. Recommend choosing appropriate message encoding format based on actual needs
4. Pay attention to monitoring Redis storage capacity, clean up historical data timely

Workflow Diagram

Message Bridge Swimlane Diagram

sequenceDiagram
    autonumber
    participant Client as MQTT Publisher
    participant Broker as MQTT Broker
    participant Bridge as Redis Bridge Plugin
    participant Subscribers as MQTT Subscribers
    participant Redis as Redis Instance Cluster

    %% MQTT message reception
    rect rgb(230, 245, 255)
        Note over Client,Subscribers: MQTT Message Flow
        Client->>Broker: 1. PUBLISH message<br/>(topic: sensors/temp)
        Broker->>Broker: 2. Topic matching check
        
        par Normal message routing
            Broker->>Subscribers: 3a. Forward to subscribers
        and Trigger bridge
            Broker->>Bridge: 3b. Trigger Redis bridge<br/>(matching topic rules)
        end
    end

    %% Message processing and encoding
    rect rgb(255, 245, 230)
        Note over Bridge,Redis: Bridge Message Processing
        Bridge->>Bridge: 4. Extract message content<br/>(topic + payload + timestamp)
        
        Bridge->>Bridge: 5. Format conversion
        alt encode=STRING
            Bridge->>Bridge: String encoding
        else encode=JSON
            Bridge->>Bridge: JSON serialization
        else encode=HEX
            Bridge->>Bridge: Hexadecimal encoding
        end
        
        Bridge->>Bridge: 6. Generate SortedSet Key<br/>(format: mqtt:topic)
        Bridge->>Bridge: 7. Get timestamp<br/>(as SortedSet score)
    end

    %% Redis write
    rect rgb(255, 255, 230)
        Note over Bridge,Redis: Parallel Write to Redis Cluster
        
        par Concurrent write to multiple instances
            Bridge->>Redis: 8a. ZADD mqtt:sensors/temp<br/>score=timestamp value=message
        and
            Bridge->>Redis: 8b. ZADD mqtt:sensors/temp<br/>score=timestamp value=message
        and
            Bridge->>Redis: 8c. ZADD mqtt:sensors/temp<br/>score=timestamp value=message
        end
        
        Redis-->>Bridge: 9. Storage confirmation response
    end

    Bridge->>Broker: 10. Bridge processing complete
    Note over Client,Redis: Message simultaneously completes<br/>MQTT routing + Redis persistence

Flow Description

1. Message Capture: Intercept MQTT messages matching specified Topic rules
2. Format Conversion: Encode messages according to configured encode parameter
3. Timestamp Marking: Use current time as SortedSet score
4. Multi-instance Write: Asynchronously parallel write to all configured Redis instances
5. Ordered Storage: Utilize Redis SortedSet feature to achieve time-ordered message storage