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routine encapsulates and provides some easy-to-use, non-competitive, high-performance goroutine context access interfaces, which can help you access coroutine context information more gracefully.

From the very beginning of its design, the Golang language has spared no effort to shield the concept of coroutine context from developers, including the acquisition of coroutine goid, the state of coroutine within the process, and the storage of coroutine context.

If you have used other languages such as C++, Java and so on, then you must be familiar with ThreadLocal, but after starting to use Golang, you will be deeply confused and distressed by the lack of convenient functions like ThreadLocal.

Of course, you can choose to use Context, which carries all the context information, appears in the first input parameter of all functions, and then shuttles around your system.

And the core goal of routine is to open up another way: Introduce goroutine local storage to the Golang world.

This chapter briefly introduces how to install and use the routine library.

go get github.com/timandy/routine

The following code simply demonstrates the use of routine.Goid():

package main

import (
	"fmt"
	"time"

	"github.com/timandy/routine"
)

func main() {
	goid := routine.Goid()
	fmt.Printf("cur goid: %v\n", goid)
	go func() {
		goid := routine.Goid()
		fmt.Printf("sub goid: %v\n", goid)
	}()

	// Wait for the sub-coroutine to finish executing.
	time.Sleep(time.Second)
}

In this example, the main function starts a new coroutine, so Goid() returns the main coroutine 1 and the child coroutine 6:

cur goid: 1
sub goid: 6

The following code briefly demonstrates ThreadLocal's creation, setting, getting, spreading across coroutines, etc.:

package main

import (
	"fmt"
	"time"

	"github.com/timandy/routine"
)

var threadLocal = routine.NewThreadLocal[string]()
var inheritableThreadLocal = routine.NewInheritableThreadLocal[string]()

func main() {
	threadLocal.Set("hello world")
	inheritableThreadLocal.Set("Hello world2")
	fmt.Println("threadLocal:", threadLocal.Get())
	fmt.Println("inheritableThreadLocal:", inheritableThreadLocal.Get())

	// The child coroutine cannot read the previously assigned "hello world".
	go func() {
		fmt.Println("threadLocal in goroutine:", threadLocal.Get())
		fmt.Println("inheritableThreadLocal in goroutine:", inheritableThreadLocal.Get())
	}()

	// However, a new sub-coroutine can be started via the Go/GoWait/GoWaitResult function, and all inheritable variables of the current coroutine can be passed automatically.
	routine.Go(func() {
		fmt.Println("threadLocal in goroutine by Go:", threadLocal.Get())
		fmt.Println("inheritableThreadLocal in goroutine by Go:", inheritableThreadLocal.Get())
	})

	// You can also create a task via the WrapTask/WrapWaitTask/WrapWaitResultTask function, and all inheritable variables of the current coroutine can be automatically captured.
	task := routine.WrapTask(func() {
		fmt.Println("threadLocal in task by WrapTask:", threadLocal.Get())
		fmt.Println("inheritableThreadLocal in task by WrapTask:", inheritableThreadLocal.Get())
	})
	go task.Run()

	// Wait for the sub-coroutine to finish executing.
	time.Sleep(time.Second)
}

The execution result is:

threadLocal: hello world
inheritableThreadLocal: Hello world2
threadLocal in goroutine:
inheritableThreadLocal in goroutine:
threadLocal in goroutine by Go:
inheritableThreadLocal in goroutine by Go: Hello world2
threadLocal in task by WrapTask:
inheritableThreadLocal in task by WrapTask: Hello world2

This chapter introduces in detail all the interfaces encapsulated by the routine library, as well as their core functions and implementation methods.

Get the goid of the current goroutine.

It can be obtained directly through assembly code under 386, amd64, armv6, armv7, arm64, loong64, mips, mipsle, mips64, mips64le, ppc64, ppc64le, riscv64, s390x, wasm architectures. This operation has extremely high performance and the time-consuming is usually only one-fifth of rand.Int().

Create a new ThreadLocal[T] instance with the initial value stored with the default value of type T.

Create a new ThreadLocal[T] instance with the initial value stored as the return value of the method supplier().

Create a new ThreadLocal[T] instance with the initial value stored with the default value of type T. When a new coroutine is started via Go(), GoWait() or GoWaitResult(), the value of the current coroutine is copied to the new coroutine. When a new task is created via WrapTask(), WrapWaitTask() or WrapWaitResultTask(), the value of the current coroutine is captured to the new task.

Create a new ThreadLocal[T] instance with the initial value stored as the return value of the method supplier(). When a new coroutine is started via Go(), GoWait() or GoWaitResult(), the value of the current coroutine is copied to the new coroutine. When a new task is created via WrapTask(), WrapWaitTask() or WrapWaitResultTask(), the value of the current coroutine is captured to the new task.

Create a new task and capture the inheritableThreadLocals from the current goroutine. This function returns a FutureTask instance, but the return task will not run automatically. You can run it in a sub-goroutine or goroutine-pool by FutureTask.Run() method, wait by FutureTask.Get() or FutureTask.GetWithTimeout() method. When the returned task run panic will be caught and error stack will be printed, the panic will be trigger again when calling FutureTask.Get() or FutureTask.GetWithTimeout() method.

Create a new task and capture the inheritableThreadLocals from the current goroutine. This function returns a FutureTask instance, but the return task will not run automatically. You can run it in a sub-goroutine or goroutine-pool by FutureTask.Run() method, wait by FutureTask.Get() or FutureTask.GetWithTimeout() method. When the returned task run panic will be caught, the panic will be trigger again when calling FutureTask.Get() or FutureTask.GetWithTimeout() method.

Create a new task and capture the inheritableThreadLocals from the current goroutine. This function returns a FutureTask instance, but the return task will not run automatically. You can run it in a sub-goroutine or goroutine-pool by FutureTask.Run() method, wait and get result by FutureTask.Get() or FutureTask.GetWithTimeout() method. When the returned task run panic will be caught, the panic will be trigger again when calling FutureTask.Get() or FutureTask.GetWithTimeout() method.

Start a new coroutine and automatically copy all contextual inheritableThreadLocals data of the current coroutine to the new coroutine. Any panic while the child coroutine is executing will be caught and the stack automatically printed.

Start a new coroutine and automatically copy all contextual inheritableThreadLocals data of the current coroutine to the new coroutine. You can wait for the sub-coroutine to finish executing through the FutureTask.Get() or FutureTask.GetWithTimeout() method that returns a value. Any panic while the child coroutine is executing will be caught and thrown again when FutureTask.Get() or FutureTask.GetWithTimeout() is called.

Start a new coroutine and automatically copy all contextual inheritableThreadLocals data of the current coroutine to the new coroutine. You can wait for the sub-coroutine to finish executing and get the return value through the FutureTask.Get() or FutureTask.GetWithTimeout() method of the return value. Any panic while the child coroutine is executing will be caught and thrown again when FutureTask.Get() or FutureTask.GetWithTimeout() is called.

More API Documentation

routine allocates a thread structure for each coroutine, which stores context variable information related to the coroutine.

A pointer to this structure is stored on the g.labels field of the coroutine structure.

When the coroutine finishes executing and exits, g.labels will be set to nil, no longer referencing the thread structure.

The thread structure will be collected at the next GC.

If the data stored in thread is not additionally referenced, these data will be collected together.

✅: Supported

Thanks to all contributors for their contributions!

routine is released under the Apache License 2.0.

Copyright 2021-2024 TimAndy

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.