86 lines
2 KiB
Go
86 lines
2 KiB
Go
package container
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import (
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"bytes"
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"context"
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"github.com/docker/docker/api/types"
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"github.com/docker/docker/client"
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"github.com/docker/docker/pkg/stdcopy"
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)
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// ExecResult represents a result returned from Exec()
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type ExecResult struct {
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ExitCode int
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outBuffer *bytes.Buffer
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errBuffer *bytes.Buffer
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}
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// Stdout returns stdout output of a command run by Exec()
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func (res *ExecResult) Stdout() string {
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return res.outBuffer.String()
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}
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// Stderr returns stderr output of a command run by Exec()
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func (res *ExecResult) Stderr() string {
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return res.errBuffer.String()
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}
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// Combined returns combined stdout and stderr output of a command run by Exec()
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func (res *ExecResult) Combined() string {
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return res.outBuffer.String() + res.errBuffer.String()
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}
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// Exec executes a command inside a container, returning the result
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// containing stdout, stderr, and exit code. Note:
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// - this is a synchronous operation;
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// - cmd stdin is closed.
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func Exec(ctx context.Context, cli client.APIClient, id string, cmd []string) (ExecResult, error) {
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// prepare exec
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execConfig := types.ExecConfig{
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AttachStdout: true,
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AttachStderr: true,
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Cmd: cmd,
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}
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cresp, err := cli.ContainerExecCreate(ctx, id, execConfig)
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if err != nil {
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return ExecResult{}, err
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}
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execID := cresp.ID
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// run it, with stdout/stderr attached
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aresp, err := cli.ContainerExecAttach(ctx, execID, types.ExecStartCheck{})
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if err != nil {
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return ExecResult{}, err
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}
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defer aresp.Close()
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// read the output
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var outBuf, errBuf bytes.Buffer
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outputDone := make(chan error, 1)
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go func() {
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// StdCopy demultiplexes the stream into two buffers
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_, err = stdcopy.StdCopy(&outBuf, &errBuf, aresp.Reader)
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outputDone <- err
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}()
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select {
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case err := <-outputDone:
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if err != nil {
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return ExecResult{}, err
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}
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break
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case <-ctx.Done():
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return ExecResult{}, ctx.Err()
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}
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// get the exit code
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iresp, err := cli.ContainerExecInspect(ctx, execID)
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if err != nil {
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return ExecResult{}, err
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}
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return ExecResult{ExitCode: iresp.ExitCode, outBuffer: &outBuf, errBuffer: &errBuf}, nil
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}
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