112 lines
2.7 KiB
Go
112 lines
2.7 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package container
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"os/exec"
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"path/filepath"
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"strings"
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"time"
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specs "github.com/opencontainers/runtime-spec/specs-go"
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"gvisor.googlesource.com/gvisor/pkg/log"
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)
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// This file implements hooks as defined in OCI spec:
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// https://github.com/opencontainers/runtime-spec/blob/master/config.md#toc22
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//
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// "hooks":{
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// "prestart":[{
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// "path":"/usr/bin/dockerd",
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// "args":[
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// "libnetwork-setkey", "arg2",
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// ]
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// }]
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// },
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// executeHooksBestEffort executes hooks and logs warning in case they fail.
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// Runs all hooks, always.
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func executeHooksBestEffort(hooks []specs.Hook, s specs.State) {
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for _, h := range hooks {
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if err := executeHook(h, s); err != nil {
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log.Warningf("Failure to execute hook %+v, err: %v", h, err)
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}
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}
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}
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// executeHooks executes hooks until the first one fails or they all execute.
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func executeHooks(hooks []specs.Hook, s specs.State) error {
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for _, h := range hooks {
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if err := executeHook(h, s); err != nil {
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return err
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}
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}
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return nil
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}
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func executeHook(h specs.Hook, s specs.State) error {
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log.Debugf("Executing hook %+v, state: %+v", h, s)
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if strings.TrimSpace(h.Path) == "" {
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return fmt.Errorf("empty path for hook")
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}
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if !filepath.IsAbs(h.Path) {
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return fmt.Errorf("path for hook is not absolute: %q", h.Path)
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}
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b, err := json.Marshal(s)
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if err != nil {
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return err
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}
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var stdout, stderr bytes.Buffer
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cmd := exec.Cmd{
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Path: h.Path,
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Args: h.Args,
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Env: h.Env,
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Stdin: bytes.NewReader(b),
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Stdout: &stdout,
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Stderr: &stderr,
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}
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if err := cmd.Start(); err != nil {
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return err
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}
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c := make(chan error, 1)
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go func() {
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c <- cmd.Wait()
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}()
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var timer <-chan time.Time
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if h.Timeout != nil {
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timer = time.After(time.Duration(*h.Timeout) * time.Second)
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}
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select {
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case err := <-c:
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if err != nil {
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return fmt.Errorf("failure executing hook %q, err: %v\nstdout: %s\nstderr: %s", h.Path, err, stdout.String(), stderr.String())
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}
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case <-timer:
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cmd.Process.Kill()
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cmd.Wait()
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return fmt.Errorf("timeout executing hook %q\nstdout: %s\nstderr: %s", h.Path, stdout.String(), stderr.String())
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}
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log.Debugf("Execute hook %q success!", h.Path)
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return nil
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}
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