netutils

README

Netutils

This is a series of networking utilities and test wrappers by entropy for building robust networked services in golang. See the godoc for details

What can I do with this?

The godoc should cover most of it. I've highlighted a few things below and will add more examples as time goes on. Examples are also present in the godoc

Mocking:

One thing peculiarity of the httmock library is you can't actually pass it a handler. WrapHandler let's you do so:

Handler Mocking:

(see mock_test for a more detailed example)

   package main
   import (
   	"github.com/jarcoal/httpmock"
   )

       func main(){
       httpmock.Activate()
       defer httpmock.Deactivate()
       ctx := context.Background()
       requestCount := 0
       testServer := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
           rw.WriteHeader(200)
       })
   
       httpmock.RegisterResponder("POST", "https://api.github.com/graphql", testutils.WrapHandler(testServer))
}   

There's also a fasthttp module for mocking fasthttp servers/clients with http mock (see tests)

Documentation

Index

• func WaitForConnect(host string) bool
• func WaitForConnectTimeout(host string, timeout time.Duration) bool
• type FreePortStack
  • func NewFreeportStack() FreePortStack
  • func (s *FreePortStack) GetFreePort() (port int, err error)
  • func (s *FreePortStack) GetPort() (port int)

Examples

• FreePortStack.GetFreePort
• WaitForConnect
• WaitForConnectTimeout

Functions

func WaitForConnect

func WaitForConnect(host string) bool

WaitForConnect on a port progressively backing off returns false if we couldn't establish a connection uses default timeout of 5 seconds

Example

WaitForConnect will attempt to connect and timeout after 10 retries of up to 5 seconds

package main

import (
	"fmt"

	"github.com/xplorfin/netutils"
)

func main() {
	// will attempt to connect and not timeout since url is valid
	successful := netutils.WaitForConnect("https://entropy.rocks")
	if successful {
		fmt.Println("connected to entropy!")
	}
}

func WaitForConnectTimeout

func WaitForConnectTimeout(host string, timeout time.Duration) bool

WaitForConnectTimeout will wait for a connection on a port progressively backing off returns false if we couldn't establish a connection by timeout after 10 timeouts

Example

WaitForConnectTimeout will attempt to connect and timeout after 5 seconds

package main

import (
	"fmt"
	"time"

	"github.com/xplorfin/netutils"
)

func main() {
	// will attempt to connect and not timeout since url is valid
	successful := netutils.WaitForConnectTimeout("https://entropy.rocks", 5*time.Second)
	if successful {
		fmt.Println("connected to entropy!")
	}

	successful = netutils.WaitForConnectTimeout("https://entropy.rockssocks", time.Millisecond)
	if !successful {
		fmt.Println("could not connect to non-existent domain")
	}
}

Types

type FreePortStack

type FreePortStack struct {
	// contains filtered or unexported fields
}

FreePortStack stack allows you to locally store a list of autogenerated ports it is stateful to make sure ports aren't reused

func NewFreeportStack

func NewFreeportStack() FreePortStack

NewFreeportStack is a helper method to initialize a freeport stack

func (*FreePortStack) GetFreePort

func (s *FreePortStack) GetFreePort() (port int, err error)

GetFreePort gets a free port that has not already been used in the stack returns errors if they exist

Example

Freeport stack gets multiple freeports that are non overlapping

package main

import (
	"github.com/xplorfin/netutils"
	"github.com/xplorfin/netutils/testutils"
)

func main() {
	// create a port stack
	stack := netutils.NewFreeportStack()

	// stack.GetPort will guarantee the ports have not been used before in the stack
	for _, port := range []int{stack.GetPort(), stack.GetPort()} {
		port := port
		go func() {
			err := testutils.MockHTTPServer(port)
			if err != nil {
				panic(err)
			}
		}()
	}
}

func (*FreePortStack) GetPort

func (s *FreePortStack) GetPort() (port int)

GetPort gets a free port that has not already been used in the stack panics on error