Monitoring

Kitex has monitoring capability built in, but does not have any monitoring features itself, and can be extended by the interface.

Custom monitoring management

The framework provides a Tracer interface. Users can implement it and inject it by WithTracer Option.

// Tracer is executed at the start and finish of an RPC.
type Tracer interface {
    Start(ctx context.Context) context.Context
    Finish(ctx context.Context)
}

For detailed documentation, refer to the Monitoring Extension section.

Expansion Repository use

kitex-contrib also provides two monitoring extensions monitor-prometheus and obs-opentelemetry. They integrate Prometheus and OpenTelemetry monitoring extensions, respectively. The former is more aligned with the Prometheus ecosystem and is easier to use, while the latter provides more flexibility.

Prometheus

The extension repository monitor-prometheus offers Prometheus monitoring extension.

usage example:

Client

import (
    "github.com/kitex-contrib/monitor-prometheus"
    kClient "github.com/cloudwego/kitex/client"
)

...

client, _ := testClient.NewClient(
    "DestServiceName",
    kClient.WithTracer(prometheus.NewClientTracer(":9091", "/kitexclient")))

resp, _ := client.Send(ctx, req)

...

Server

import (
    "github.com/kitex-contrib/monitor-prometheus"
    kServer "github.com/cloudwego/kitex/server"
)

func main() {
...
	svr := xxxservice.NewServer(
	    &myServiceImpl{},
	    kServer.WithTracer(prometheus.NewServerTracer(":9092", "/kitexserver")))
	svr.Run()
...
}

Metrics

Client

Name Unit Tags Description
kitex_client_throughput - type, caller, callee, method, status Total number of requests handled by the Client
kitex_client_latency_us us type, caller, callee, method, status Latency of request handling at the Client (Response received time - Request initiation time, in microseconds)

Server

Name Unit Tags Description
kitex_server_throughput - type, caller, callee, method, status Total number of requests handled by the Server
kitex_server_latency_us us type, caller, callee, method, status Latency of request handling at the Server (Processing completion time - Request received time, in microseconds)

More complex data monitoring can be implemented based on the above metrics. Examples can be found in the Useful Examples section.

Runtime Metrics

This repository relies on prometheus/client_golang and supports its built-in runtime metrics. For more details, please refer to WithGoCollectorRuntimeMetrics.

OpenTelemetry

The extension repository obs-opentelemetry provides OpenTelemetry monitoring extension.

usage example:

For information on how to use obs-opentelemetry, please refer to the tracing section.

Metrics

Server

Name Metric Data Model Unit Unit(UCUM) Description
rpc.server.duration Histogram milliseconds ms measures duration of inbound RPC

Client

Name Metric Data Model Unit Unit(UCUM) Description
rpc.server.duration Histogram milliseconds ms measures duration of outbound RPC

Additional service metrics can be calculated using rpc.server.duration, such as R.E.D (Rate, Errors, Duration). Examples can be found here.

Runtime Metrics

Based on opentelemetry-go, it supports the following runtime metrics:

Name Instrument Unit Unit (UCUM)) Description
process.runtime.go.cgo.calls Sum - - Number of cgo calls made by the current process.
process.runtime.go.gc.count Sum - - Number of completed garbage collection cycles.
process.runtime.go.gc.pause_ns Histogram nanosecond ns Amount of nanoseconds in GC stop-the-world pauses.
process.runtime.go.gc.pause_total_ns Histogram nanosecond ns Cumulative nanoseconds in GC stop-the-world pauses since the program started.
process.runtime.go.goroutines Gauge - - measures duration of outbound RPC.
process.runtime.go.lookups Sum - - Number of pointer lookups performed by the runtime.
process.runtime.go.mem.heap_alloc Gauge bytes bytes Bytes of allocated heap objects.
process.runtime.go.mem.heap_idle Gauge bytes bytes Bytes in idle (unused) spans.
process.runtime.go.mem.heap_inuse Gauge bytes bytes Bytes in in-use spans.
process.runtime.go.mem.heap_objects Gauge - - Number of allocated heap objects.
process.runtime.go.mem.live_objects Gauge - - Number of live objects is the number of cumulative Mallocs - Frees.
process.runtime.go.mem.heap_released Gauge bytes bytes Bytes of idle spans whose physical memory has been returned to the OS.
process.runtime.go.mem.heap_sys Gauge bytes bytes Bytes of idle spans whose physical memory has been returned to the OS.
runtime.uptime Sum ms ms Milliseconds since application was initialized.

Last modified February 29, 2024 : doc: optimize cli document (#982) (6126084)