pool

README

Pool

Pool is a simple and generic connection pool written in Golang. It can be used to manage and reuse resources that are expensive to create or destroy, such as network connections or database connections.

⚠️ This README file was generated by ChatGPT. I cannot guarantee that everything is correct. Use this library at your own risk, and please report any issues or inaccuracies you may find.

Installation

To install the package, run the following command:

go get github.com/cdfmlr/pool

Usage

To use the pool, create a new pool instance using the NewPool function and provide two arguments: the maximum number of resources that can be created and a function that creates new resources.

maxLen := 10
createFunc := func() (Poolable, error) {
    // create new resource
}

p := NewPool(maxLen, createFunc)

Once you've created the pool, you can use the following methods to interact with it:

• Get() (T, error) - Get a resource from the pool. If the pool is empty, a new resource will be created if the maximum pool size has not been reached.
• Put(T) error - Put a resource back into the pool. If the pool is full, the resource will be closed and discarded.
• Release(T) error - Release an unused resource from the pool and close it. Releasing a resource that was not obtained from the pool will break the consistency of the pool.
• Len() int - Get the current size of the pool.
• Idle() int- Get the current number of idle resources in the pool.
• Close() error - Close the pool and release all resources.

Example

package main

import (
    "fmt"
    "github.com/cdfmlr/pool"
)

type MyResource struct {
    id int
}

func (r *MyResource) Close() error {
    fmt.Printf("Closing resource %d\n", r.id)
    return nil
}

func main() {
    maxLen := 2
    createFunc := func() (pool.Poolable, error) {
        return &MyResource{id: 0}, nil
    }

    p := pool.NewPool(maxLen, createFunc)

    // Get a resource from the pool
    r1, err := p.Get()
    if err != nil {
        panic(err)
    }
    fmt.Printf("Got resource %d\n", r1.(*MyResource).id)

    // Put the resource back into the pool
    if err := p.Put(r1); err != nil {
        panic(err)
    }
    fmt.Printf("Put resource %d back into the pool\n", r1.(*MyResource).id)

    // Get another resource from the pool
    r2, err := p.Get()
    if err != nil {
        panic(err)
    }
    fmt.Printf("Got resource %d\n", r2.(*MyResource).id)

    // Release the resource back intothe pool and close it
    if err := p.Release(r2); err != nil {
        panic(err)
    }
    fmt.Printf("Released and closed resource %d\n", r2.(*MyResource).id)

    // Close the pool and release all resources
    if err := p.Close(); err != nil {
        panic(err)
    }
}

Error Handling

The following errors may be returned by methods in the Pool interface:

• ErrPoolClosed - The pool has been closed and no new resources can be obtained.
• ErrPoolExhausted - The pool has reached its maximum capacity and no new resources can be created.

Documentation

Overview

Package pool provide a generic connection pool.

Package pool provide a generic connection pool.

Index

• Variables
• type Pool
  • func NewPool[T Poolable](maxLen int64, createT func() (T, error)) Pool[T]
• type Poolable

Variables

var (
	ErrPoolClosed    = errors.New("the pool is closed")
	ErrPoolExhausted = errors.New("the pool has been exhausted")
)

errors

Types

type Pool

type Pool[T Poolable] interface {
	Get() (T, error) // Get a T from the pool
	Put(T) error     // Put T back
	Release(T) error // Release unused T from pool, and Close it. Release a T that is not Get from Pool breaks the consistency!
	Len() int        // Len is current pool size
	Close() error    // Close the pool: Refuse to Get, Release all holding/Putting-back resources.
}

func NewPool

func NewPool[T Poolable](maxLen int64, createT func() (T, error)) Pool[T]

type Poolable

type Poolable interface {
	io.Closer
}