refactor gracehttp for readability
This commit is contained in:
Naitik Shah
parent
aad68df4be
commit
d1f693d1d4
@ -16,40 +16,66 @@ import (
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"github.com/daaku/go.grace"
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)
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type serverSlice []*http.Server
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var (
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verbose = flag.Bool("gracehttp.log", true, "Enable logging.")
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errListenersCount = errors.New("unexpected listeners count")
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verbose = flag.Bool("gracehttp.log", true, "Enable logging.")
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errListenersCount = errors.New("unexpected listeners count")
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errNoStartedListeners = errors.New("no started listeners")
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)
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// Creates new listeners for all the given addresses.
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func (servers serverSlice) newListeners() ([]grace.Listener, error) {
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listeners := make([]grace.Listener, len(servers))
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for index, pair := range servers {
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addr, err := net.ResolveTCPAddr("tcp", pair.Addr)
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// Defines an application containing various servers and associated
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// configuration.
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type App struct {
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Servers []*http.Server
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listeners []grace.Listener
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errors chan error
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}
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// Inherit or create new listeners. Returns a bool indicating if we inherited
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// listeners. This return value is useful in order to decide if we should
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// instruct the parent process to terminate.
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func (a *App) Listen() (bool, error) {
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var err error
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a.errors = make(chan error, len(a.Servers))
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a.listeners, err = grace.Inherit()
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if err == nil {
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if len(a.Servers) != len(a.listeners) {
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return true, errListenersCount
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}
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return true, nil
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} else if err == grace.ErrNotInheriting {
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if a.listeners, err = a.newListeners(); err != nil {
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return false, err
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}
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return false, nil
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}
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return false, fmt.Errorf("Failed graceful handoff: %s", err)
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}
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// Creates new listeners (as in not inheriting) for all the configured Servers.
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func (a *App) newListeners() ([]grace.Listener, error) {
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listeners := make([]grace.Listener, len(a.Servers))
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for index, server := range a.Servers {
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addr, err := net.ResolveTCPAddr("tcp", server.Addr)
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if err != nil {
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return nil, fmt.Errorf(
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"Failed net.ResolveTCPAddr for %s: %s", pair.Addr, err)
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return nil, fmt.Errorf("net.ResolveTCPAddr %s: %s", server.Addr, err)
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}
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l, err := net.ListenTCP("tcp", addr)
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if err != nil {
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return nil, fmt.Errorf("Failed net.ListenTCP for %s: %s", pair.Addr, err)
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return nil, fmt.Errorf("net.ListenTCP %s: %s", server.Addr, err)
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}
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listeners[index] = grace.NewListener(l)
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}
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return listeners, nil
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}
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// Serve on the given listeners and wait for signals.
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func (servers serverSlice) serveWait(listeners []grace.Listener) error {
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if len(servers) != len(listeners) {
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return errListenersCount
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}
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errch := make(chan error, len(listeners)+1) // listeners + grace.Wait
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for i, l := range listeners {
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// Serve the configured servers, but do not block. You must call Wait at some
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// point to ensure correctly waiting for graceful termination.
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func (a *App) Serve() {
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for i, l := range a.listeners {
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go func(i int, l net.Listener) {
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server := servers[i]
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server := a.Servers[i]
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// Wrap the listener for TLS support if necessary.
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if server.TLSConfig != nil {
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l = tls.NewListener(l, server.TLSConfig)
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}
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@ -58,61 +84,65 @@ func (servers serverSlice) serveWait(listeners []grace.Listener) error {
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// The underlying Accept() will return grace.ErrAlreadyClosed
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// when a signal to do the same is returned, which we are okay with.
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if err != nil && err != grace.ErrAlreadyClosed {
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errch <- fmt.Errorf("Failed http.Serve: %s", err)
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a.errors <- fmt.Errorf("http.Serve: %s", err)
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}
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}(i, l)
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}
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go func() {
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err := grace.Wait(listeners)
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if err != nil {
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errch <- fmt.Errorf("Failed grace.Wait: %s", err)
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} else {
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errch <- nil
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}
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}()
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return <-errch
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}
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// Wait for the serving goroutines to finish.
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func (a *App) Wait() error {
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waiterr := make(chan error)
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go func() { waiterr <- grace.Wait(a.listeners) }()
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select {
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case err := <-waiterr:
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return err
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case err := <-a.errors:
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return err
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}
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}
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// Serve will serve the given pairs of addresses and listeners and
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// will monitor for signals allowing for graceful termination (SIGTERM)
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// or restart (SIGUSR2).
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func Serve(servers ...*http.Server) error {
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sslice := serverSlice(servers)
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listeners, err := grace.Inherit()
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if err == nil {
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err = grace.CloseParent()
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if err != nil {
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return fmt.Errorf("Failed to close parent: %s", err)
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}
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if *verbose {
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ppid := os.Getppid()
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if ppid == 1 {
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log.Printf("Listening on init activated %s", pprintAddr(listeners))
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} else {
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log.Printf(
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"Graceful handoff of %s with new pid %d and old pid %d.",
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pprintAddr(listeners), os.Getpid(), ppid)
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}
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}
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} else if err == grace.ErrNotInheriting {
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listeners, err = sslice.newListeners()
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if err != nil {
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return err
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}
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if *verbose {
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log.Printf("Serving %s with pid %d.", pprintAddr(listeners), os.Getpid())
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}
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} else {
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return fmt.Errorf("Failed graceful handoff: %s", err)
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}
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err = sslice.serveWait(listeners)
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app := &App{Servers: servers}
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inherited, err := app.Listen()
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if err != nil {
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return err
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}
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if *verbose {
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if inherited {
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ppid := os.Getppid()
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if ppid == 1 {
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log.Printf("Listening on init activated %s", pprintAddr(app.listeners))
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} else {
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const msg = "Graceful handoff of %s with new pid %d and old pid %d"
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log.Printf(msg, pprintAddr(app.listeners), os.Getpid(), ppid)
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}
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} else {
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const msg = "Serving %s with pid %d"
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log.Printf(msg, pprintAddr(app.listeners), os.Getpid())
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}
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}
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app.Serve()
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// Close the parent if we inherited and it wasn't init that started us.
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if inherited && os.Getppid() != 1 {
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if err := grace.CloseParent(); err != nil {
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return fmt.Errorf("Failed to close parent: %s", err)
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}
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}
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err = app.Wait()
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if *verbose {
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log.Printf("Exiting pid %d.", os.Getpid())
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}
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return nil
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return err
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}
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// Used for pretty printing addresses.
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@ -7,13 +7,10 @@ import (
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"flag"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"os"
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"os/exec"
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"path/filepath"
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"sync"
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"syscall"
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"testing"
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@ -23,8 +20,13 @@ import (
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"github.com/daaku/go.tool"
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)
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// Debug logging.
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var debugLog = flag.Bool("debug", false, "enable debug logging")
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var (
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// Debug logging.
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debugLog = flag.Bool("debug", false, "enable debug logging")
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testserverCommand = &tool.CommandBuild{
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ImportPath: "github.com/daaku/go.grace/gracehttp/testserver",
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}
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)
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func debug(format string, a ...interface{}) {
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if *debugLog {
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@ -38,34 +40,6 @@ var (
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buildOnce sync.Once
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)
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// Builds the command.
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func build(t *testing.T) string {
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buildOnce.Do(func() {
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const pkg = "github.com/daaku/go.grace/gracehttp/testserver"
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basename := filepath.Base(pkg)
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tempFile, err := ioutil.TempFile("", basename+"-")
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if err != nil {
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buildErr = err
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return
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}
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buildOut = tempFile.Name()
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_ = os.Remove(buildOut) // the build tool will create this
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options := tool.Options{
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ImportPaths: []string{pkg},
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Output: buildOut,
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}
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_, err = options.Command("build")
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if err != nil {
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buildErr = err
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return
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}
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})
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if buildErr != nil {
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t.Fatal(buildErr)
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}
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return buildOut
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}
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// The response from the test server.
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type response struct {
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Sleep time.Duration
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@ -104,8 +78,13 @@ func (h *harness) setupAddr() {
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// Start a fresh server and wait for pid updates on restart.
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func (h *harness) Start() {
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bin, err := testserverCommand.Build()
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if err != nil {
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h.T.Fatalf("build error: %s", err)
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}
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h.setupAddr()
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cmd := exec.Command(build(h.T), "-http", h.httpAddr, "-https", h.httpsAddr)
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cmd := exec.Command(bin, "-http", h.httpAddr, "-https", h.httpsAddr)
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stderr, err := cmd.StderrPipe()
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if err != nil {
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h.T.Fatal(err)
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@ -118,22 +97,22 @@ func (h *harness) Start() {
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return
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}
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if err != nil {
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log.Fatalf("Failed to read line from server process: %s", err)
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println(fmt.Sprintf("Failed to read line from server process: %s", err))
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}
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if isPrefix {
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log.Fatalf("Deal with isPrefix for line: %s", line)
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println(fmt.Sprintf("Deal with isPrefix for line: %s", line))
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}
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res := &response{}
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err = json.Unmarshal([]byte(line), res)
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if err != nil {
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log.Fatalf("Could not parse json from stderr %s: %s", line, err)
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println(fmt.Sprintf("Could not parse json from stderr %s: %s", line, err))
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}
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if res.Error != "" {
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println(fmt.Sprintf("Got error from process: %v", res))
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}
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process, err := os.FindProcess(res.Pid)
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if err != nil {
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log.Fatalf("Could not find process with pid: %d", res.Pid)
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println(fmt.Sprintf("Could not find process with pid: %d", res.Pid))
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}
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h.ProcessMutex.Lock()
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h.Process = append(h.Process, process)
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