RocketMQ-Rust Macros

Using macros to automate repetitive tasks.

Overview

This crate is primarily for the macros used in RocketMQ-Rust. The currently defined macros are as follows:

• RequestHeaderCodec(Derive Macros)
• RemotingSerializable(Derive Macros) - Currently not in use, implemented via alternative methods.

RequestHeaderCodec Macro

The RequestHeaderCodec macro implements serialization and deserialization for RocketMQ's RequestHeader. It automatically implements the CommandCustomHeader trait and the FromMap trait. This macro includes an attribute: required, which indicates that a field of the struct must be present during deserialization; otherwise, it will result in an error.

Note: The required attribute corresponds to the @CFNotNull annotation in the Java version and is implemented in this way in Rust.

Example usage is shown below:

#[derive(Debug, Clone, Serialize, Deserialize, Default, RequestHeaderCodec)]
#[serde(rename_all = "camelCase")]
pub struct SendMessageRequestHeader {
    #[required]  // this field is required
    pub producer_group: CheetahString,
    pub topic: CheetahString,
    pub default_topic: CheetahString,
    pub default_topic_queue_nums: i32,
    pub queue_id: Option<i32>,
    pub sys_flag: i32,
    pub born_timestamp: i64,
    pub flag: i32,
    pub properties: Option<CheetahString>,
    pub reconsume_times: Option<i32>,
    pub unit_mode: Option<bool>,
    pub batch: Option<bool>,
    pub max_reconsume_times: Option<i32>,
    #[serde(flatten)]
    pub topic_request_header: Option<TopicRequestHeader>,
}

In this example, the SendMessageRequestHeader struct is annotated with the RequestHeaderCodec derive macro, along with other standard Rust attributes like Debug, Clone, Serialize, Deserialize, and Default. The #[required] attribute is used on the producer_group field to denote that it is mandatory for successful deserialization.