dotcloud/docker

package container

import (
    "bytes"
    "context"
    "testing"

    "github.com/docker/docker/api/types/container"
    "github.com/docker/docker/client"
)

// 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()
}

// AssertSuccess fails the test and stops execution if the command exited with a
// nonzero status code.
func (res ExecResult) AssertSuccess(t testing.TB) {
    t.Helper()
    if res.ExitCode != 0 {
        t.Logf("expected exit code 0, got %d", res.ExitCode)
        t.Logf("stdout: %s", res.Stdout())
        t.Logf("stderr: %s", res.Stderr())
        t.FailNow()
    }
}

// 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, apiClient client.APIClient, id string, cmd []string, ops ...func(*container.ExecOptions)) (ExecResult, error) {
    // prepare exec
    execOptions := container.ExecOptions{
        AttachStdout: true,
        AttachStderr: true,
        Cmd:          cmd,
    }

    for _, op := range ops {
        op(&execOptions)
    }

    cresp, err := apiClient.ContainerExecCreate(ctx, id, execOptions)
    if err != nil {
        return ExecResult{}, err
    }
    execID := cresp.ID

    // run it, with stdout/stderr attached
    aresp, err := apiClient.ContainerExecAttach(ctx, execID, container.ExecAttachOptions{})
    if err != nil {
        return ExecResult{}, err
    }

    // read the output
    s, err := demultiplexStreams(ctx, aresp)
    if err != nil {
        return ExecResult{}, err
    }

    // get the exit code
    iresp, err := apiClient.ContainerExecInspect(ctx, execID)
    if err != nil {
        return ExecResult{}, err
    }

    return ExecResult{ExitCode: iresp.ExitCode, outBuffer: &s.stdout, errBuffer: &s.stderr}, nil
}

// ExecT calls Exec() and aborts the test if an error occurs.
func ExecT(ctx context.Context, t testing.TB, apiClient client.APIClient, id string, cmd []string, ops ...func(*container.ExecOptions)) ExecResult {
    t.Helper()
    res, err := Exec(ctx, apiClient, id, cmd, ops...)
    if err != nil {
        t.Fatal(err)
    }
    return res
}