wbs

wbs

Watch, build, and (re)start Go net/http server, customizeable by toml configuration file

Why created

This tool is yet another auto-rebuild-reloader for go net/http. This tool uses flexible toml configuration file, makes it possible to use gb, gom, make, or any other command with environmental variables to build binary. It also have bunch of tests, and keeping code structure simple to make it easy to contribute.

Installation

go get -u github.com/achiku/wbs

Configuration Example

root_path = "."

watch_target_dirs = ["."]
watch_exclude_dirs = [".git", "vendor", "bin"]
watch_file_ext = [".go", ".tmpl", ".html"]
# usually used when we need to ignore files generated by `go generate`
# need to include dir path
watch_file_exclude_pattern = [
    "example/lib/*_gen.go",
    "example/lib/bindata.go"
]
# this option forces wbs only watch directory, not files.
# if you are using vim/neovim set this option `true`
# vim/neovim do not fire events that fsnotify can capture for file.
watch_dir_only = false

# Env vars can be used in build_target_dir, build_target_name,  build_command,
# build_options, start_options
build_target_dir = "$GOPATH/bin"
build_target_name = "myserver"
build_command = "go"
build_options = ["build", "-v"]

# start command will be `build_target_dir/build_target_name start_options`
# in this case $GOPATH/bin/myserver -v
start_options = ["-v", "-p", "$APP_PORT"]

# default true, but it's possible to make this fale, when
# running a program that doesn't persist as a process
restart_process = true

Quick Start

Save the following net/http application to main.go.

package main

import (
	"fmt"
	"log"
	"net/http"
	"time"
)

func loggingMiddleware(next http.Handler) http.Handler {
	fn := func(w http.ResponseWriter, r *http.Request) {
		t1 := time.Now()
		next.ServeHTTP(w, r)
		t2 := time.Now()
		log.Printf("[%s] %q %v\n", r.Method, r.URL.String(), t2.Sub(t1))
	}
	return http.HandlerFunc(fn)
}

func helloWorld(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Hello, world!\n")
}

func main() {
	helloWorldHandler := http.HandlerFunc(helloWorld)
	http.Handle("/hello", loggingMiddleware(helloWorldHandler))
	if err := http.ListenAndServe(":8080", nil); err != nil {
		log.Fatal(err)
	}
}

≫≫ ls -l
total 8
-rw-r--r--  1 achiku  staff  636  2  7 14:24 main.go

Then, just type wbs. This will build binary, and start watching files specified.

≫≫ wbs
14:50:58 watcher     |start watching main.go
14:50:58 builder     |starting build: go [build -v -o tmp/server]
14:50:59 builder     |
github.com/achiku/wbs/example
14:50:59 runner      |starting server: tmp/server [-v]
14:50:59 runner      |starting server: PID 41797

You can specify configuration file using -c option.

≫≫ wbs -c wbs.example.toml
14:51:58 watcher     |start watching main.go
14:51:58 builder     |starting build: go [build -v -o tmp/server]
14:51:59 builder     |
github.com/achiku/wbs/example
14:51:59 runner      |starting server: tmp/server [-v]
14:51:59 runner      |starting server: PID 41797

Application stdout and stderr goes to wbs stderr.

≫≫ for i in $(seq 1 3); do curl http://localhost:8080/hello; done
Hello, world!
Hello, world!
Hello, world!

14:55:23 runner      |2016/02/07 14:55:23 [GET] "/hello" 5.74µs
14:55:25 runner      |2016/02/07 14:55:25 [GET] "/hello" 5.692µs
14:55:26 runner      |2016/02/07 14:55:26 [GET] "/hello" 7.323µs

When main.go is modified, wbs will rebuild binary, and restart server.

14:59:54 main        |file modified: "main.go": WRITE
14:59:54 runner      |stopping server: PID 44000
14:59:54 builder     |starting build: go [build -v -o tmp/server]
14:59:56 builder     |
github.com/achiku/wbs/example
14:59:56 runner      |starting server: tmp/server [-v]
14:59:56 runner      |starting server: PID 44036

Test

$ go test -v

Inspired by

• https://github.com/pilu/fresh