From 87fb2c973d8f9a8a1868ab0c2da504095d04715b Mon Sep 17 00:00:00 2001
From: Brandon Philips <brandon@ifup.co>
Date: Fri, 6 Dec 2013 21:19:30 -0800
Subject: [PATCH] server: add socket activation
This adds the ability to socket activate docker by passing in
`-H fd://*` along with examples systemd configuration files.
The fastest way to test this is to run:
```
/usr/lib/systemd/systemd-activate -l 127.0.0.1:2001 /usr/bin/docker -d -H 'fd://*'
docker -H tcp://127.0.0.1:2001 ps
```
Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)
---
api.go | 64 +++++++++++++++++--
.../systemd/socket-activation/docker.service | 11 ++++
.../systemd/socket-activation/docker.socket | 8 +++
server.go | 26 ++++----
systemd/listendfd.go | 41 ++++++++++++
utils/utils.go | 2 +
6 files changed, 130 insertions(+), 22 deletions(-)
create mode 100644 contrib/init/systemd/socket-activation/docker.service
create mode 100644 contrib/init/systemd/socket-activation/docker.socket
create mode 100644 systemd/listendfd.go
diff --git a/api.go b/api.go
index bf9f29b57f..e522583087 100644
--- a/api.go
+++ b/api.go
@@ -24,6 +24,7 @@ import (
"regexp"
"strconv"
"strings"
+ "syscall"
)
const (
@@ -1081,16 +1082,66 @@ func ServeRequest(srv *Server, apiversion float64, w http.ResponseWriter, req *h
return nil
}
+// ServeFD creates an http.Server and sets it up to serve given a socket activated
+// argument.
+func ServeFd(addr string, handle http.Handler) error {
+ ls, e := systemd.ListenFD(addr)
+ if e != nil {
+ return e
+ }
+
+ chErrors := make(chan error, len(ls))
+
+ // Since ListenFD will return one or more sockets we have
+ // to create a go func to spawn off multiple serves
+ for i, _ := range(ls) {
+ listener := ls[i]
+ go func () {
+ httpSrv := http.Server{Handler: handle}
+ chErrors <- httpSrv.Serve(listener)
+ }()
+ }
+
+ for i := 0; i < len(ls); i += 1 {
+ err := <-chErrors
+ if err != nil {
+ return err
+ }
+ }
+
+ return nil
+}
+
+// ListenAndServe sets up the required http.Server and gets it listening for
+// each addr passed in and does protocol specific checking.
func ListenAndServe(proto, addr string, srv *Server, logging bool) error {
r, err := createRouter(srv, logging)
if err != nil {
return err
}
- l, e := net.Listen(proto, addr)
- if e != nil {
- return e
+
+ if proto == "fd" {
+ return ServeFd(addr, r)
}
+
if proto == "unix" {
+ if err := syscall.Unlink(addr); err != nil && !os.IsNotExist(err) {
+ return err
+ }
+ }
+
+ l, err := net.Listen(proto, addr)
+ if err != nil {
+ return err
+ }
+
+ // Basic error and sanity checking
+ switch proto {
+ case "tcp":
+ if !strings.HasPrefix(addr, "127.0.0.1") {
+ log.Println("/!\\ DON'T BIND ON ANOTHER IP ADDRESS THAN 127.0.0.1 IF YOU DON'T KNOW WHAT YOU'RE DOING /!\\")
+ }
+ case "unix":
if err := os.Chmod(addr, 0660); err != nil {
return err
}
@@ -1110,11 +1161,10 @@ func ListenAndServe(proto, addr string, srv *Server, logging bool) error {
return err
}
}
+ default:
+ return fmt.Errorf("Invalid protocol format.")
}
- httpSrv := http.Server{Addr: addr, Handler: r}
- log.Printf("Listening for HTTP on %s (%s)\n", addr, proto)
- // Tell the init daemon we are accepting requests
- go systemd.SdNotify("READY=1")
+ httpSrv := http.Server{Addr: addr, Handler: r}
return httpSrv.Serve(l)
}
diff --git a/contrib/init/systemd/socket-activation/docker.service b/contrib/init/systemd/socket-activation/docker.service
new file mode 100644
index 0000000000..0b39c28328
--- /dev/null
+++ b/contrib/init/systemd/socket-activation/docker.service
@@ -0,0 +1,11 @@
+[Unit]
+Description=Docker Application Container Engine
+Documentation=http://docs.docker.io
+After=network.target
+
+[Service]
+ExecStartPre=/bin/mount --make-rprivate /
+ExecStart=/usr/bin/docker -d -H fd://*
+
+[Install]
+WantedBy=multi-user.target
diff --git a/contrib/init/systemd/socket-activation/docker.socket b/contrib/init/systemd/socket-activation/docker.socket
new file mode 100644
index 0000000000..3635c89385
--- /dev/null
+++ b/contrib/init/systemd/socket-activation/docker.socket
@@ -0,0 +1,8 @@
+[Unit]
+Description=Docker Socket for the API
+
+[Socket]
+ListenStream=/var/run/docker.sock
+
+[Install]
+WantedBy=sockets.target
diff --git a/server.go b/server.go
index b4add79771..b87ec659f8 100644
--- a/server.go
+++ b/server.go
@@ -10,6 +10,7 @@ import (
"github.com/dotcloud/docker/pkg/cgroups"
"github.com/dotcloud/docker/pkg/graphdb"
"github.com/dotcloud/docker/registry"
+ "github.com/dotcloud/docker/systemd"
"github.com/dotcloud/docker/utils"
"io"
"io/ioutil"
@@ -114,29 +115,20 @@ func jobInitApi(job *engine.Job) engine.Status {
return engine.StatusOK
}
+// ListenAndServe loops through all of the protocols sent in to docker and spawns
+// off a go routine to setup a serving http.Server for each.
func (srv *Server) ListenAndServe(job *engine.Job) engine.Status {
protoAddrs := job.Args
chErrors := make(chan error, len(protoAddrs))
+
for _, protoAddr := range protoAddrs {
protoAddrParts := strings.SplitN(protoAddr, "://", 2)
- switch protoAddrParts[0] {
- case "unix":
- if err := syscall.Unlink(protoAddrParts[1]); err != nil && !os.IsNotExist(err) {
- log.Fatal(err)
- }
- case "tcp":
- if !strings.HasPrefix(protoAddrParts[1], "127.0.0.1") {
- log.Println("/!\\ DON'T BIND ON ANOTHER IP ADDRESS THAN 127.0.0.1 IF YOU DON'T KNOW WHAT YOU'RE DOING /!\\")
- }
- default:
- job.Errorf("Invalid protocol format.")
- return engine.StatusErr
- }
- go func() {
- // FIXME: merge Server.ListenAndServe with ListenAndServe
+ go func () {
+ log.Printf("Listening for HTTP on %s (%s)\n", protoAddrParts[0], protoAddrParts[1])
chErrors <- ListenAndServe(protoAddrParts[0], protoAddrParts[1], srv, job.GetenvBool("Logging"))
}()
}
+
for i := 0; i < len(protoAddrs); i += 1 {
err := <-chErrors
if err != nil {
@@ -144,6 +136,10 @@ func (srv *Server) ListenAndServe(job *engine.Job) engine.Status {
return engine.StatusErr
}
}
+
+ // Tell the init daemon we are accepting requests
+ go systemd.SdNotify("READY=1")
+
return engine.StatusOK
}
diff --git a/systemd/listendfd.go b/systemd/listendfd.go
new file mode 100644
index 0000000000..a8fdb09ca4
--- /dev/null
+++ b/systemd/listendfd.go
@@ -0,0 +1,41 @@
+package systemd
+
+import (
+ "errors"
+ "fmt"
+ "net"
+ "strconv"
+
+ "github.com/coreos/go-systemd/activation"
+)
+
+// ListenFD returns the specified socket activated files as a slice of
+// net.Listeners or all of the activated files if "*" is given.
+func ListenFD(addr string) ([]net.Listener, error) {
+ files := activation.Files(false)
+ if files == nil || len(files) == 0 {
+ return nil, errors.New("No sockets found")
+ }
+
+ fdNum, _ := strconv.Atoi(addr)
+ fdOffset := fdNum - 3
+ if (addr != "*") && (len(files) < int(fdOffset)+1) {
+ return nil, errors.New("Too few socket activated files passed in")
+ }
+
+ // socket activation
+ listeners := make([]net.Listener, len(files))
+ for i, f := range files {
+ var err error
+ listeners[i], err = net.FileListener(f)
+ if err != nil {
+ return nil, fmt.Errorf("Error setting up FileListener for fd %d: %s", f.Fd(), err.Error())
+ }
+ }
+
+ if addr == "*" {
+ return listeners, nil
+ }
+
+ return []net.Listener{listeners[fdOffset]}, nil
+}
diff --git a/utils/utils.go b/utils/utils.go
index 2a11397212..542ab49702 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -767,6 +767,8 @@ func ParseHost(defaultHost string, defaultPort int, defaultUnix, addr string) (s
case strings.HasPrefix(addr, "tcp://"):
proto = "tcp"
addr = strings.TrimPrefix(addr, "tcp://")
+ case strings.HasPrefix(addr, "fd://"):
+ return addr, nil
case addr == "":
proto = "unix"
addr = defaultUnix