forked from flannel-io/flannel
/
extension.go
151 lines (125 loc) · 3.81 KB
/
extension.go
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// Copyright 2017 flannel authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package extension
import (
"fmt"
"io"
"strings"
"os/exec"
"encoding/json"
log "github.com/golang/glog"
"github.com/coreos/flannel/backend"
"github.com/coreos/flannel/pkg/ip"
"github.com/coreos/flannel/subnet"
"golang.org/x/net/context"
)
func init() {
backend.Register("extension", New)
}
type ExtensionBackend struct {
sm subnet.Manager
extIface *backend.ExternalInterface
networks map[string]*network
}
func New(sm subnet.Manager, extIface *backend.ExternalInterface) (backend.Backend, error) {
be := &ExtensionBackend{
sm: sm,
extIface: extIface,
networks: make(map[string]*network),
}
return be, nil
}
func (_ *ExtensionBackend) Run(ctx context.Context) {
<-ctx.Done()
}
func (be *ExtensionBackend) RegisterNetwork(ctx context.Context, config *subnet.Config) (backend.Network, error) {
n := &network{
extIface: be.extIface,
sm: be.sm,
}
// Parse out configuration
if len(config.Backend) > 0 {
cfg := struct {
PreStartupCommand string
PostStartupCommand string
SubnetAddCommand string
SubnetRemoveCommand string
}{}
if err := json.Unmarshal(config.Backend, &cfg); err != nil {
return nil, fmt.Errorf("error decoding backend config: %v", err)
}
n.preStartupCommand = cfg.PreStartupCommand
n.postStartupCommand = cfg.PostStartupCommand
n.subnetAddCommand = cfg.SubnetAddCommand
n.subnetRemoveCommand = cfg.SubnetRemoveCommand
}
data := []byte{}
if len(n.preStartupCommand) > 0 {
cmd_output, err := runCmd([]string{}, "", "sh", "-c", n.preStartupCommand)
if err != nil {
return nil, fmt.Errorf("failed to run command: %s Err: %v Output: %s", n.preStartupCommand, err, cmd_output)
} else {
log.Infof("Ran command: %s\n Output: %s", n.preStartupCommand, cmd_output)
}
data, err = json.Marshal(cmd_output)
if err != nil {
return nil, err
}
} else {
log.Infof("No pre startup command configured - skipping")
}
attrs := subnet.LeaseAttrs{
PublicIP: ip.FromIP(be.extIface.ExtAddr),
BackendType: "extension",
BackendData: data,
}
lease, err := be.sm.AcquireLease(ctx, &attrs)
switch err {
case nil:
n.lease = lease
case context.Canceled, context.DeadlineExceeded:
return nil, err
default:
return nil, fmt.Errorf("failed to acquire lease: %v", err)
}
if len(n.postStartupCommand) > 0 {
cmd_output, err := runCmd([]string{
fmt.Sprintf("NETWORK=%s", config.Network),
fmt.Sprintf("SUBNET=%s", lease.Subnet),
fmt.Sprintf("PUBLIC_IP=%s", attrs.PublicIP)},
"", "sh", "-c", n.postStartupCommand)
if err != nil {
return nil, fmt.Errorf("failed to run command: %s Err: %v Output: %s", n.postStartupCommand, err, cmd_output)
} else {
log.Infof("Ran command: %s\n Output: %s", n.postStartupCommand, cmd_output)
}
} else {
log.Infof("No post startup command configured - skipping")
}
return n, nil
}
// Run a cmd, returning a combined stdout and stderr.
func runCmd(env []string, stdin string, name string, arg ...string) (string, error) {
cmd := exec.Command(name, arg...)
cmd.Env = env
stdinpipe, err := cmd.StdinPipe()
if err != nil {
return "", err
}
io.WriteString(stdinpipe, stdin)
io.WriteString(stdinpipe, "\n")
stdinpipe.Close()
output, err := cmd.CombinedOutput()
return strings.TrimSpace(string(output)), err
}