Add executor package to run commands inside containers

Signed-off-by: Lou Marvin Caraig <[email protected]>

internal/executor/executor.go

@@ -0,0 +1,109 @@
+package executor
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/client"
+	"github.com/se7entyse7en/pydockenv/log"
+	"github.com/sirupsen/logrus"
+)
+
+func ExecuteForContainer(container types.ContainerJSON, cmd []string, options *ExecOptions) error {
+	logger := log.Logger
+	cli, err := client.NewClientWithOpts(client.FromEnv)
+	if err != nil {
+		return err
+	}
+
+	hostBaseWd := container.Config.Labels["workdir"]
+	wd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("cannot get working directory: %w", err)
+	}
+
+	if !strings.HasPrefix(wd, hostBaseWd) && !options.ByPassCheck {
+		return fmt.Errorf("cannot run commands outside of %s", hostBaseWd)
+	}
+
+	relativeWd := wd[len(hostBaseWd):]
+	guestWd := fmt.Sprintf("/usr/src%s", relativeWd)
+
+	ctxLogger := logger.WithFields(logrus.Fields{
+		"command": strings.Join(cmd, " "),
+	})
+
+	ctxLogger.Debug("Running command...")
+	idResp, err := cli.ContainerExecCreate(context.Background(), container.Name,
+		types.ExecConfig{
+			Tty:          true,
+			AttachStdin:  !options.Detach,
+			AttachStderr: true,
+			AttachStdout: true,
+			Detach:       options.Detach,
+			Env:          buildEnv(options.EnvVars),
+			WorkingDir:   guestWd,
+			Cmd:          cmd,
+		})
+	if err != nil {
+		return fmt.Errorf("cannot create command '%s' in container '%s': %w",
+			cmd, container.ID, err)
+	}
+
+	resp, err := cli.ContainerExecAttach(context.Background(), idResp.ID, types.ExecStartCheck{})
+	if err != nil {
+		return fmt.Errorf("cannot execute command '%s' in container '%s': %w",
+			cmd, container.ID, err)
+	}
+
+	defer resp.Close()
+
+	for {
+		header := make([]byte, 8)
+		_, err = io.ReadFull(resp.Reader, header)
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+
+			return err
+		}
+
+		size := binary.BigEndian.Uint32(header[4:])
+		body := make([]byte, size)
+		_, err = io.ReadFull(resp.Reader, body)
+		if err != nil {
+			return err
+		}
+
+		if header[0] == 1 {
+			os.Stdout.Write(body)
+		} else {
+			os.Stderr.Write(body)
+		}
+	}
+
+	ctxLogger.Debug("Command ran")
+	return nil
+}
+
+func buildEnv(envMapping map[string]string) []string {
+	var env []string
+	for k, v := range envMapping {
+		env = append(env, fmt.Sprintf("%s=%s", k, v))
+	}
+
+	return env
+}
+
+type ExecOptions struct {
+	ByPassCheck bool
+	Detach      bool
+	EnvVars     map[string]string
+	Ports       []int
+}