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