pool

README

sleep

A generic resource pool with maxOpen, maxIdle and usability checking.

Documentation

Index

• type OpenFunc
• type Pool
  • func New(open OpenFunc, usable UsableFunc, maxOpen, maxIdle int) (*Pool, error)
  • func New2(open OpenFunc, usable UsableFunc, values url.Values) (*Pool, error)
  • func (p *Pool) Close(r *Resource) error
  • func (p *Pool) Get(ctx context.Context) (*Resource, error)
  • func (p *Pool) Put(r *Resource) error
• type Resource
  • func (r *Resource) Resource() io.Closer
• type UsableFunc

Examples

• Pool

Types

type OpenFunc

type OpenFunc func(context.Context) (io.Closer, error)

the func to open a resource

type Pool

type Pool struct {
	sync.Mutex
	// contains filtered or unexported fields
}

Example

var pool, err = New(func(ctx context.Context) (io.Closer, error) {
	return net.Dial("tcp", "baidu.com:80")
}, func(ctx context.Context, r *Resource) bool {
	if time.Since(r.IdleAt) < time.Minute {
		return true
	}
	// check if r.Resource() is usable, may be by a ping or noop operation
	return true
}, 5, 2)
if err != nil {
	panic(err)
}

// this can also be doing concurrently
for i := 0; i < 10; i++ {
	ctx, _ := context.WithTimeout(context.Background(), 5*time.Second)
	// get a connection
	resource, err := pool.Get(ctx)
	if err != nil {
		panic(err)
	}

	// do some work with the connection ...
	conn := resource.Resource().(net.Conn)
	conn.Write(nil)

	// put the connection back
	if err := pool.Put(resource); err != nil {
		panic(err)
	}
}

func New

func New(open OpenFunc, usable UsableFunc, maxOpen, maxIdle int) (*Pool, error)

func New2

func New2(open OpenFunc, usable UsableFunc, values url.Values) (*Pool, error)

New2 return a pool by params from url.Values. Params default value: maxOpen => 10; maxIdle => 1;

func (*Pool) Close

func (p *Pool) Close(r *Resource) error

Close a resource got from the pool. The resource must be got from the pool and be `Close`d only one time, otherwise an error is returned.

func (*Pool) Get

func (p *Pool) Get(ctx context.Context) (*Resource, error)

func (*Pool) Put

func (p *Pool) Put(r *Resource) error

Put a resource back into the pool. The resource must be got from the pool and be `Put` only one time, otherwise an error is returned.

type Resource

type Resource struct {
	io.Closer
	IdleAt   time.Time
	OpenedAt time.Time
}

func (*Resource) Resource

func (r *Resource) Resource() io.Closer

type UsableFunc

type UsableFunc func(context.Context, *Resource) bool

the func to check if a resource is usable.