golang代码执行顺序
Posted 黑手党老k
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一：首先man.go，整个程序的入口
func main() {
beego.Run()
}
然后beego.run()代码
// Run beego application.
// beego.Run() default run on HttpPort
// beego.Run(":8089")
// beego.Run("127.0.0.1:8089")
func Run(params ...string) {
if len(params) > 0 && params[0] != "" {
strs := strings.Split(params[0], ":")
if len(strs) > 0 && strs[0] != "" {
HttpAddr = strs[0]
}
if len(strs) > 1 && strs[1] != "" {
HttpPort, _ = strconv.Atoi(strs[1])
}
}
initBeforeHttpRun()
if EnableAdmin {
go beeAdminApp.Run()
}
BeeApp.Run()
}
可以看出来，beego.run()可以带参数。
beego.run()在默认的主机、端口号上运行，beego.run(port)在给定的端口号、默认的主机上运行。beego.run(addr：post)在给定的主机和端口上运行。
下面看看initBeforeHttpRun()的代码。
func initBeforeHttpRun() {
// if AppConfigPath not In the conf/app.conf reParse config
if AppConfigPath != filepath.Join(AppPath, "conf", "app.conf") {
err := ParseConfig()
if err != nil && AppConfigPath != filepath.Join(workPath, "conf", "app.conf") {
// configuration is critical to app, panic here if parse failed
panic(err)
}
}
// do hooks function
for _, hk := range hooks {
err := hk()
if err != nil {
panic(err)
}
}
if SessionOn {
var err error
sessionConfig := AppConfig.String("sessionConfig")
if sessionConfig == "" {
sessionConfig = `{"cookieName":"` + SessionName + `",` +
`"gclifetime":` + strconv.FormatInt(SessionGCMaxLifetime, 10) + `,` +
`"providerConfig":"` + SessionSavePath + `",` +
`"secure":` + strconv.FormatBool(EnableHttpTLS) + `,` +
`"sessionIDHashFunc":"` + SessionHashFunc + `",` +
`"sessionIDHashKey":"` + SessionHashKey + `",` +
`"enableSetCookie":` + strconv.FormatBool(SessionAutoSetCookie) + `,` +
`"domain":"` + SessionDomain + `",` +
`"cookieLifeTime":` + strconv.Itoa(SessionCookieLifeTime) + `}`
}
GlobalSessions, err = session.NewManager(SessionProvider,
sessionConfig)
if err != nil {
panic(err)
}
go GlobalSessions.GC()
}
err := BuildTemplate(ViewsPath)
if err != nil {
if RunMode == "dev" {
Warn(err)
}
}
middleware.VERSION = VERSION
middleware.AppName = AppName
middleware.RegisterErrorHandler()
if EnableDocs {
Get("/docs", serverDocs)
Get("/docs/*", serverDocs)
}
//init mime
AddAPPStartHook(initMime)
}
可以看到首先拼凑出来的是conf配置文件的路劲，如果存在然后调用ParseConfig()解析conf。
然后是
for _, hk := range hooks {
err := hk()
if err != nil {
panic(err)
}
}
hooks的定义
type hookfunc func() error //hook function to run
var hooks []hookfunc //hook function slice to store the hookfunc
func init() {
hooks = make([]hookfunc, 0)
}
hooks是一个hookfun的切片，
// The hookfunc will run in beego.Run()
// such as sessionInit, middlerware start, buildtemplate, admin start
func AddAPPStartHook(hf hookfunc) {
hooks = append(hooks, hf)
}
上面的代码是在启动的时候添加自己的方法hook。也就是hooks是在启动之前，留给用户初始化一些东西的时候。
if SessionOn {
var err error
sessionConfig := AppConfig.String("sessionConfig")
if sessionConfig == "" {
sessionConfig = `{"cookieName":"` + SessionName + `",` +
`"gclifetime":` + strconv.FormatInt(SessionGCMaxLifetime, 10) + `,` +
`"providerConfig":"` + SessionSavePath + `",` +
`"secure":` + strconv.FormatBool(EnableHttpTLS) + `,` +
`"sessionIDHashFunc":"` + SessionHashFunc + `",` +
`"sessionIDHashKey":"` + SessionHashKey + `",` +
`"enableSetCookie":` + strconv.FormatBool(SessionAutoSetCookie) + `,` +
`"domain":"` + SessionDomain + `",` +
`"cookieLifeTime":` + strconv.Itoa(SessionCookieLifeTime) + `}`
}
GlobalSessions, err = session.NewManager(SessionProvider,
sessionConfig)
if err != nil {
panic(err)
}
go GlobalSessions.GC()
}
err := BuildTemplate(ViewsPath)
if err != nil {
if RunMode == "dev" {
Warn(err)
}
}
下面就开始来解析conf文件。如果sessionConfig为空，就使用默认的json数据。然后就开始根据提供的config配置文件创建一个sessionmanager对象
这是session.NewManager()方法的实现
// Create new Manager with provider name and json config string.
// provider name:
// 1. cookie
// 2. file
// 3. memory
// 4. redis
// 5. mysql
// json config:
// 1. is https default false
// 2. hashfunc default sha1
// 3. hashkey default beegosessionkey
// 4. maxage default is none
func NewManager(provideName, config string) (*Manager, error) {
provider, ok := provides[provideName]
if !ok {
return nil, fmt.Errorf("session: unknown provide %q (forgotten import?)", provideName)
}
cf := new(managerConfig)
cf.EnableSetCookie = true
err := json.Unmarshal([]byte(config), cf)
if err != nil {
return nil, err
}
if cf.Maxlifetime == 0 {
cf.Maxlifetime = cf.Gclifetime
}
err = provider.SessionInit(cf.Maxlifetime, cf.ProviderConfig)
if err != nil {
return nil, err
}
if cf.SessionIDHashFunc == "" {
cf.SessionIDHashFunc = "sha1"
}
if cf.SessionIDHashKey == "" {
cf.SessionIDHashKey = string(generateRandomKey(16))
}
return &Manager{
provider,
cf,
}, nil
}
可以推测。session.NewManager(SessionProvider,sessionConfig)中SessionProvider是一个全局变量，使用的是在config.go中默认的SessionProvider = "memory"，然后改方法返回的是一个Manager的指针对象，即*Manager，所以GlobalSessions是一个*Manager对象。
然后启动一个携程执行GC()方法。下面是GC的源码
// Start session gc process.
// it can do gc in times after gc lifetime.
func (manager *Manager) GC() {
manager.provider.SessionGC()
time.AfterFunc(time.Duration(manager.config.Gclifetime)*time.Second, func() { manager.GC() })
}
所以上面的代码是一个无限循环，每隔一段time。DUration之后执行GC().
err := BuildTemplate(ViewsPath)
if err != nil {
if RunMode == "dev" {
Warn(err)
}
}
这里就开始编译模板了。
// build all template files in a directory.
// it makes beego can render any template file in view directory.
func BuildTemplate(dir string) error {
if _, err := os.Stat(dir); err != nil {
if os.IsNotExist(err) {
return nil
} else {
return errors.New("dir open err")
}
}
self := &templatefile{
root: dir,
files: make(map[string][]string),
}
err := filepath.Walk(dir, func(path string, f os.FileInfo, err error) error {
return self.visit(path, f, err)
})
if err != nil {
fmt.Printf("filepath.Walk() returned %v\\n", err)
return err
}
for _, v := range self.files {
for _, file := range v {
t, err := getTemplate(self.root, file, v...)
if err != nil {
Trace("parse template err:", file, err)
} else {
BeeTemplates[file] = t
}
}
}
return nil
}
首先判断目录是否存在。目录ViewsPath在config中有初始化。然后初始化templatefile结构体，filepath.Walk()走一边目录里的文件，记录在self.files里面。循环self.files中的file（map[dir][]file])，用getTemplate获取template.Template实例，保存在beego.BeeTemplates（map[string]template.Template）。
然后是
middleware.VERSION = VERSION
middleware.AppName = AppName
middleware.RegisterErrorHandler()
if EnableDocs {
Get("/docs", serverDocs)
Get("/docs/*", serverDocs)
}
//init mime
AddAPPStartHook(initMime)
middleware包括的是错误处理的功能。如NotFound()、Forbidden()、Errorhandler()等等处理。。
随后的AddAPPStartHook(initMine)则是初始化所有的minetype类型的函数。
上面的代码实在beego项目启动前需要操作的比如初始化conf配置、编译模板文件、注册错误处理中间件、加载所有的mimetype类型、
然后继续回到beego.run()代码中间
if EnableAdmin {
go beeAdminApp.Run()
}
BeeApp.Run()
很简单。如果beego允许admin。则执行beeAdminApp。beeAdminApp也是一个*beego.adminApp，负责系统监控、性能检测、访问统计和健康检查等。然后猪线程运行BeeApp.Run()方法，开始执行beego。
下面看看beego.adminApp的代码
// adminApp is an http.HandlerFunc map used as beeAdminApp.
type adminApp struct {
routers map[string]http.HandlerFunc
}
// Route adds http.HandlerFunc to adminApp with url pattern.
func (admin *adminApp) Route(pattern string, f http.HandlerFunc) {
admin.routers[pattern] = f
}
// Run adminApp http server.
// Its addr is defined in configuration file as adminhttpaddr and adminhttpport.
func (admin *adminApp) Run() {
if len(toolbox.AdminTaskList) > 0 {
toolbox.StartTask()
}
addr := AdminHttpAddr
if AdminHttpPort != 0 {
addr = fmt.Sprintf("%s:%d", AdminHttpAddr, AdminHttpPort)
}
for p, f := range admin.routers {
http.Handle(p, f)
}
err := http.ListenAndServe(addr, nil)
if err != nil {
BeeLogger.Critical("Admin ListenAndServe: ", err)
}
}
// task interface
type Tasker interface {
GetStatus() string
Run() error
SetNext(time.Time)
GetNext() time.Time
SetPrev(time.Time)
GetPrev() time.Time
}
AdminTaskList map[string]Tasker
// start all tasks
func StartTask() {
isstart = true
go run()
}
func run() {
now := time.Now().Local()
for _, t := range AdminTaskList {
t.SetNext(now)
}
for {
sortList := NewMapSorter(AdminTaskList)
sortList.Sort()
var effective time.Time
if len(AdminTaskList) == 0 || sortList.Vals[0].GetNext().IsZero() {
// If there are no entries yet, just sleep - it still handles new entries
// and stop requests.
effective = now.AddDate(10, 0, 0)
} else {
effective = sortList.Vals[0].GetNext()
}
select {
case now = <-time.After(effective.Sub(now)):
// Run every entry whose next time was this effective time.
for _, e := range sortList.Vals {
if e.GetNext() != effective {
break
}
go e.Run()
e.SetPrev(e.GetNext())
e.SetNext(effective)
}
continue
case <-changed:
continue
case <-stop:
return
}
}
}
// start all tasks
func StopTask() {
isstart = false
stop <- true
}
// add task with name
func AddTask(taskname string, t Tasker) {
AdminTaskList[taskname] = t
if isstart {
changed <- true
}
}
// add task with name
func DeleteTask(taskname string) {
delete(AdminTaskList, taskname)
if isstart {
changed <- true
}
}
adminApp结构体里面只有map结构的router，toolbox.AdminTaskList是一个map类型的结构。如果AdminTaskList中间有Tasker。则开始执行StartTask()，而且，StartTask()方法中实现的是另外打开一个协程执行Run()方法。最后打开http.ListenAndServe()实现监听。
下面是BeeApp.Run()
package beego
import (
"fmt"
"net"
"net/http"
"net/http/fcgi"
"time"
"github.com/astaxie/beego/context"
)
// FilterFunc defines filter function type.
type FilterFunc func(*context.Context)
// App defines beego application with a new PatternServeMux.
type App struct {
Handlers *ControllerRegistor
Server *http.Server
}
// NewApp returns a new beego application.
func NewApp() *App {
cr := NewControllerRegister()
app := &App{Handlers: cr, Server: &http.Server{}}
return app
}
// Run beego application.
func (app *App) Run() {
addr := HttpAddr
if HttpPort != 0 {
addr = fmt.Sprintf("%s:%d", HttpAddr, HttpPort)
}
BeeLogger.Info("Running on %s", addr)
var (
err error
l net.Listener
)
endRunning := make(chan bool, 1)
if UseFcgi {
if HttpPort == 0 {
l, err = net.Listen("unix", addr)
} else {
l, err = net.Listen("tcp", addr)
}
if err != nil {
BeeLogger.Critical("Listen: ", err)
}
err = fcgi.Serve(l, app.Handlers)
} else {
app.Server.Addr = addr
app.Server.Handler = app.Handlers
app.Server.ReadTimeout = time.Duration(HttpServerTimeOut) * time.Second
app.Server.WriteTimeout = time.Duration(HttpServerTimeOut) * time.Second
if EnableHttpTLS {
go func() {
time.Sleep(20 * time.Microsecond)
if HttpsPort != 0 {
app.Server.Addr = fmt.Sprintf("%s:%d", HttpAddr, HttpsPort)
}
err := app.Server.ListenAndServeTLS(HttpCertFile, HttpKeyFile)
if err != nil {
BeeLogger.Critical("ListenAndServeTLS: ", err)
time.Sleep(100 * time.Microsecond)
endRunning <- true
}
}()
}
if EnableHttpListen {
go func() {
app.Server.Addr = addr
err := app.Server.ListenAndServe()
if err != nil {
BeeLogger.Critical("ListenAndServe: ", err)
time.Sleep(100 * time.Microsecond)
endRunning <- true
}
}()
}
}
<-endRunning
}
上面的代码首先是获取地址addr，然后执行fast-cgi,调用ListenAndServeTLS监听cgi服务，后面的是Http服务，调用ListenAndServe()监听http服务。
func ListenAndServe(addr string, handler Handler) error {
server := &Server{Addr: addr, Handler: handler}
return server.ListenAndServe()
}
// ListenAndServe listens on the TCP network address srv.Addr and then
// calls Serve to handle requests on incoming connections. If
// srv.Addr is blank, ":http" is used.
func (srv *Server) ListenAndServe() error {
addr := srv.Addr
if addr == "" {
addr = ":http"
}
ln, err := net.Listen("tcp", addr)
if err != nil {
return err
}
return srv.Serve(tcpKeepAliveListener{ln.(*net.TCPListener)})
}
// Serve accepts incoming connections on the Listener l, creating a
// new service goroutine for each. The service goroutines read requests and
// then call srv.Handler to reply to them.
func (srv *Server) Serve(l net.Listener) error {
defer l.Close()
var tempDelay time.Duration // how long to sleep on accept failure
for {
rw, e := l.Accept()
if e != nil {
if ne, ok := e.(net.Error); ok && ne.Temporary() {
if tempDelay == 0 {
tempDelay = 5 * time.Millisecond
} else {
tempDelay *= 2
}
if max := 1 * time.Second; tempDelay > max {
tempDelay = max
}
srv.logf("http: Accept error: %v; retrying in %v", e, tempDelay)
time.Sleep(tempDelay)
continue
}
return e
}
tempDelay = 0
c, err := srv.newConn(rw)
if err != nil {
continue
}
c.setState(c.rwc, StateNew) // before Serve can return
go c.serve()
}
}
ListenAndServe()的功能：
1、初始化一个Server
2、调用Server的ListenAndServe()
3、调用net.Listen(“tcp”, addr)监听端口
4、启动一个for循环，在循环体中Accept请求
5、对每个请求实例化一个Conn，并且开启一个goroutine为这个请求进行服务go c.serve()
下面看看进入c.serve()方法的源码
// Serve a new connection.
func (c *conn) serve() {
origConn := c.rwc // copy it before it\'s set nil on Close or Hijack
defer func() {
if err := recover(); err != nil {
const size = 64 << 10
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
c.server.logf("http: panic serving %v: %v\\n%s", c.remoteAddr, err, buf)
}
if !c.hijacked() {
c.close()
c.setState(origConn, StateClosed)
}
}()
if tlsConn, ok := c.rwc.(*tls.Conn); ok {
if d := c.server.ReadTimeout; d != 0 {
c.rwc.SetReadDeadline(time.Now().Add(d))
}
if d := c.server.WriteTimeout; d != 0 {
c.rwc.SetWriteDeadline(time.Now().Add(d))
}
if err := tlsConn.Handshake(); err != nil {
c.server.logf("http: TLS handshake error from %s: %v", c.rwc.RemoteAddr(), err)
return
}
c.tlsState = new(tls.ConnectionState)
*c.tlsState = tlsConn.ConnectionState()
if proto := c.tlsState.NegotiatedProtocol; validNPN(proto) {
if fn := c.server.TLSNextProto[proto]; fn != nil {
h := initNPNRequest{tlsConn, serverHandler{c.server}}
fn(c.server, tlsConn, h)
}
return
}
}
for {
w, err := c.readRequest()
if c.lr.N != c.server.initialLimitedReaderSize() {
// If we read any bytes off the wire, we\'re active.
c.setState(c.rwc, StateActive)
}
if err != nil {
if err == errTooLarge {
// Their HTTP client may or may not be
// able to read this if we\'re
// responding to them and hanging up
// while they\'re still writing their
// request. Undefined behavior.
io.WriteString(c.rwc, "HTTP/1.1 413 Request Entity Too Large\\r\\n\\r\\n")
c.closeWriteAndWait()
break
} else if err == io.EOF {
break // Don\'t reply
} else if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
break // Don\'t reply
}
io.WriteString(c.rwc, "HTTP/1.1 400 Bad Request\\r\\n\\r\\n")
break
}
// Expect 100 Continue support
req := w.req
if req.expectsContinue() {
if req.ProtoAtLeast(1, 1) && req.ContentLength != 0 {
// Wrap the Body reader with one that replies on the connection
req.Body = &expectContinueReader{readCloser: req.Body, resp: w}
}
req.Header.Del("Expect")
} else if req.Header.get("Expect") != "" {
w.sendExpectationFailed()
break
}
// HTTP cannot have multiple simultaneous active requests.[*]
// Until the server replies to this request, it can\'t read another,
// so we might as well run the handler in this goroutine.
// [*] Not strictly true: HTTP pipelining. We could let them all process
// in parallel even if their responses need to be serialized.
serverHandler{c.server}.ServeHTTP(w, w.req)
if c.hijacked() {
return
}
w.finishRequest()
if w.closeAfterReply {
if w.requestBodyLimitHit {
c.closeWriteAndWait()
}
break
}
c.setState(c.rwc, StateIdle)
}
}
上面的代码实现：
1、读取每个请求的内容w, err := c.readRequest()
2、判断handler是否为空，如果没有设置handler（这个例子就没有设置handler），handler就设置为DefaultServeMux
3、调用handler的ServeHttp
4、根据request选择handler，并且进入到这个handler的ServeHTTP
5、选择handler
下面就开始Http请求的过程了。上文中提到的handler在beego项目中就是beego.ControllerRegistor结构体，下面是ControllerRegistor的源码。可以看见。实现了http.handler接口的ServeHTTP方法。而且，上下文对象context也被初始化了。后面的do_filter就是实现过滤方法的实现。然后就是判断请求的方法、seesion等函数。
而且还有一个很重要的就是runrouter、runMethod、findrouter、routerInfo这四个参数，在方法开头就已经定义了。
// ControllerRegistor containers registered router rules, controller handlers and filters.
type ControllerRegistor struct {
routers map[string]*Tree
enableFilter bool
filters map[int][]*FilterRouter
}
// Implement http.Handler interface.
func (p *ControllerRegistor) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
defer p.recoverPanic(rw, r)
starttime := time.Now()
var runrouter reflect.Type
var findrouter bool
var runMethod string
var routerInfo *controllerInfo
w := &responseWriter{writer: rw}
if RunMode == "dev" {
w.Header().Set("Server", BeegoServerName)
}
// init context
context := &beecontext.Context{
ResponseWriter: w,
Request: r,
Input: beecontext.NewInput(r),
Output: beecontext.NewOutput(),
}
context.Output.Context = context
context.Output.EnableGzip = EnableGzip
// defined filter function
do_filter := func(pos int) (started bool) {
if p.enableFilter {
if l, ok := p.filters[pos]; ok {
for _, filterR := range l {
if ok, p := filterR.ValidRouter(r.URL.Path); ok {
context.Input.Params = p
filterR.filterFunc(context)
if w.started {
return true
}
}
}
}
}
return false
}
// filter wrong httpmethod
if _, ok := HTTPMETHOD[r.Method]; !ok {
http.Error(w, "Method Not Allowed", 405)
goto Admin
}
// filter for static file
if do_filter(BeforeStatic) {
goto Admin
}
serverStaticRouter(context)
if w.started {
findrouter = true
goto Admin
}
// session init
if SessionOn {
context.Input.CruSession = GlobalSessions.SessionStart(w, r)
defer func() {
context.Input.CruSession.SessionRelease(w)
}()
}
if r.Method != "golang代码片段（摘抄）