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// Copyright 2016 CNI 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 invoke
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"os/exec"
"strings"
"time"
"github.com/containernetworking/cni/pkg/types"
)
type RawExec struct {
Stderr io.Writer
}
func (e *RawExec) ExecPlugin(ctx context.Context, pluginPath string, stdinData []byte, environ []string) ([]byte, error) {
stdout := &bytes.Buffer{}
stderr := &bytes.Buffer{}
c := exec.CommandContext(ctx, pluginPath)
c.Env = environ
c.Stdin = bytes.NewBuffer(stdinData)
c.Stdout = stdout
c.Stderr = stderr
// Retry the command on "text file busy" errors
for i := 0; i <= 5; i++ {
err := c.Run()
// Command succeeded
if err == nil {
break
}
// If the plugin is currently about to be written, then we wait a
// second and try it again
if strings.Contains(err.Error(), "text file busy") {
time.Sleep(time.Second)
continue
}
// All other errors except than the busy text file
return nil, e.pluginErr(err, stdout.Bytes(), stderr.Bytes())
}
// Copy stderr to caller's buffer in case plugin printed to both
// stdout and stderr for some reason. Ignore failures as stderr is
// only informational.
if e.Stderr != nil && stderr.Len() > 0 {
_, _ = stderr.WriteTo(e.Stderr)
}
return stdout.Bytes(), nil
}
func (e *RawExec) pluginErr(err error, stdout, stderr []byte) error {
emsg := types.Error{}
if len(stdout) == 0 {
if len(stderr) == 0 {
emsg.Msg = fmt.Sprintf("netplugin failed with no error message: %v", err)
} else {
emsg.Msg = fmt.Sprintf("netplugin failed: %q", string(stderr))
}
} else if perr := json.Unmarshal(stdout, &emsg); perr != nil {
emsg.Msg = fmt.Sprintf("netplugin failed but error parsing its diagnostic message %q: %v", string(stdout), perr)
}
return &emsg
}
func (e *RawExec) FindInPath(plugin string, paths []string) (string, error) {
return FindInPath(plugin, paths)
}
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