预热

通过客户端预热,可以避免首次请求时产生较大的延迟。

介绍

kitex v0.3.0 支持了客户端预热,可以在创建客户端的时候预先初始化服务发现和连接池的相关组件,避免在首次请求时产生较大的延迟。

使用方式

v0.3.0 新增 API

NewClient 方法的 option:

client.WithWarmingUp(w *warmup.ClientOption) Option

其中 warmup.ClientOption 是 v0.3.0 版本引入的 package pkg/warmup 提供的结构体:

// ClientOption controls the warming up of a client.
type ClientOption struct {
    ErrorHandling
    ResolverOption *ResolverOption
    PoolOption     *PoolOption
}
// ErrorHandling controls how to handle error
type ErrorHandling int

// ErrorHandling .
const (
    IgnoreError ErrorHandling = iota
    WarningLog
    ErrorLog
    FailFast // fail if any error occurs.
)

// ResolverOption controls the warming up of service discovery.
type ResolverOption struct {
    Dests []*rpcinfo.EndpointBasicInfo
}

// PoolOption controls the warming up of connection pools.
type PoolOption struct {
    Targets  map[string][]string // Network => addresses; if nil, use the result of service discovery
    ConnNum  int                 // Connection numbers for each address
    Parallel int                 // If greater than zero, build connections in `Parallel` goroutines.
}

常见用法

创建 client 的时候执行服务发现

cli, err := myservice.NewClient(psm, client.WithWarmingUp(&warmup.ClientOption{
    ResolverOption: &warmup.ResolverOption{
        Dests: []*rpcinfo.EndpointBasicInfo{
            &rpcinfo.EndpointBasicInfo{
                ServiceName: psm,
                Tags: map[string]string{
                    "cluster": "default",
                    // "env": "xxx"
                },
            },
        },
    },
}))

创建 client 的时候初始化连接池,每个下游实例建立两个连接

cli, err := myservice.NewClient(psm, client.WithWarmingUp(&warmup.ClientOption{
    PoolOption: &warmup.PoolOption{
        ConnNum: 2,
    },
}))

FAQ

Q:下游升级后会重新预热吗?

不会。


最后修改 February 29, 2024 : doc: optimize cli document (#982) (6126084)