feat(agent): implement recreate for devcontainers (#17308)

This change implements an interface for running `@devcontainers/cli up`
and an API endpoint on the agent for triggering recreate for a running
devcontainer.

A couple of limitations:

1. Synchronous HTTP request, meaning the browser might choose to time it
out before it's done => no result/error (and devcontainer cli command
probably gets killed via ctx cancel).
2. Logs are only written to agent logs via slog, not as a "script" in
the UI.

Both 1 and 2 will be improved in future refactors.

Fixes coder/internal#481
Fixes coder/internal#482

agent/agentcontainers/devcontainercli.go

@@ -0,0 +1,193 @@
+package agentcontainers
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+
+	"golang.org/x/xerrors"
+
+	"cdr.dev/slog"
+	"github.com/coder/coder/v2/agent/agentexec"
+)
+
+// DevcontainerCLI is an interface for the devcontainer CLI.
+type DevcontainerCLI interface {
+	Up(ctx context.Context, workspaceFolder, configPath string, opts ...DevcontainerCLIUpOptions) (id string, err error)
+}
+
+// DevcontainerCLIUpOptions are options for the devcontainer CLI up
+// command.
+type DevcontainerCLIUpOptions func(*devcontainerCLIUpConfig)
+
+// WithRemoveExistingContainer is an option to remove the existing
+// container.
+func WithRemoveExistingContainer() DevcontainerCLIUpOptions {
+	return func(o *devcontainerCLIUpConfig) {
+		o.removeExistingContainer = true
+	}
+}
+
+type devcontainerCLIUpConfig struct {
+	removeExistingContainer bool
+}
+
+func applyDevcontainerCLIUpOptions(opts []DevcontainerCLIUpOptions) devcontainerCLIUpConfig {
+	conf := devcontainerCLIUpConfig{
+		removeExistingContainer: false,
+	}
+	for _, opt := range opts {
+		if opt != nil {
+			opt(&conf)
+		}
+	}
+	return conf
+}
+
+type devcontainerCLI struct {
+	logger slog.Logger
+	execer agentexec.Execer
+}
+
+var _ DevcontainerCLI = &devcontainerCLI{}
+
+func NewDevcontainerCLI(logger slog.Logger, execer agentexec.Execer) DevcontainerCLI {
+	return &devcontainerCLI{
+		execer: execer,
+		logger: logger,
+	}
+}
+
+func (d *devcontainerCLI) Up(ctx context.Context, workspaceFolder, configPath string, opts ...DevcontainerCLIUpOptions) (string, error) {
+	conf := applyDevcontainerCLIUpOptions(opts)
+	logger := d.logger.With(slog.F("workspace_folder", workspaceFolder), slog.F("config_path", configPath), slog.F("recreate", conf.removeExistingContainer))
+
+	args := []string{
+		"up",
+		"--log-format", "json",
+		"--workspace-folder", workspaceFolder,
+	}
+	if configPath != "" {
+		args = append(args, "--config", configPath)
+	}
+	if conf.removeExistingContainer {
+		args = append(args, "--remove-existing-container")
+	}
+	cmd := d.execer.CommandContext(ctx, "devcontainer", args...)
+
+	var stdout bytes.Buffer
+	cmd.Stdout = io.MultiWriter(&stdout, &devcontainerCLILogWriter{ctx: ctx, logger: logger.With(slog.F("stdout", true))})
+	cmd.Stderr = &devcontainerCLILogWriter{ctx: ctx, logger: logger.With(slog.F("stderr", true))}
+
+	if err := cmd.Run(); err != nil {
+		if _, err2 := parseDevcontainerCLILastLine(ctx, logger, stdout.Bytes()); err2 != nil {
+			err = errors.Join(err, err2)
+		}
+		return "", err
+	}
+
+	result, err := parseDevcontainerCLILastLine(ctx, logger, stdout.Bytes())
+	if err != nil {
+		return "", err
+	}
+
+	return result.ContainerID, nil
+}
+
+// parseDevcontainerCLILastLine parses the last line of the devcontainer CLI output
+// which is a JSON object.
+func parseDevcontainerCLILastLine(ctx context.Context, logger slog.Logger, p []byte) (result devcontainerCLIResult, err error) {
+	s := bufio.NewScanner(bytes.NewReader(p))
+	var lastLine []byte
+	for s.Scan() {
+		b := s.Bytes()
+		if len(b) == 0 || b[0] != '{' {
+			continue
+		}
+		lastLine = b
+	}
+	if err = s.Err(); err != nil {
+		return result, err
+	}
+	if len(lastLine) == 0 || lastLine[0] != '{' {
+		logger.Error(ctx, "devcontainer result is not json", slog.F("result", string(lastLine)))
+		return result, xerrors.Errorf("devcontainer result is not json: %q", string(lastLine))
+	}
+	if err = json.Unmarshal(lastLine, &result); err != nil {
+		logger.Error(ctx, "parse devcontainer result failed", slog.Error(err), slog.F("result", string(lastLine)))
+		return result, err
+	}
+
+	return result, result.Err()
+}
+
+// devcontainerCLIResult is the result of the devcontainer CLI command.
+// It is parsed from the last line of the devcontainer CLI stdout which
+// is a JSON object.
+type devcontainerCLIResult struct {
+	Outcome string `json:"outcome"` // "error", "success".
+
+	// The following fields are set if outcome is success.
+	ContainerID           string `json:"containerId"`
+	RemoteUser            string `json:"remoteUser"`
+	RemoteWorkspaceFolder string `json:"remoteWorkspaceFolder"`
+
+	// The following fields are set if outcome is error.
+	Message     string `json:"message"`
+	Description string `json:"description"`
+}
+
+func (r devcontainerCLIResult) Err() error {
+	if r.Outcome == "success" {
+		return nil
+	}
+	return xerrors.Errorf("devcontainer up failed: %s (description: %s, message: %s)", r.Outcome, r.Description, r.Message)
+}
+
+// devcontainerCLIJSONLogLine is a log line from the devcontainer CLI.
+type devcontainerCLIJSONLogLine struct {
+	Type      string `json:"type"`      // "progress", "raw", "start", "stop", "text", etc.
+	Level     int    `json:"level"`     // 1, 2, 3.
+	Timestamp int    `json:"timestamp"` // Unix timestamp in milliseconds.
+	Text      string `json:"text"`
+
+	// More fields can be added here as needed.
+}
+
+// devcontainerCLILogWriter splits on newlines and logs each line
+// separately.
+type devcontainerCLILogWriter struct {
+	ctx    context.Context
+	logger slog.Logger
+}
+
+func (l *devcontainerCLILogWriter) Write(p []byte) (n int, err error) {
+	s := bufio.NewScanner(bytes.NewReader(p))
+	for s.Scan() {
+		line := s.Bytes()
+		if len(line) == 0 {
+			continue
+		}
+		if line[0] != '{' {
+			l.logger.Debug(l.ctx, "@devcontainer/cli", slog.F("line", string(line)))
+			continue
+		}
+		var logLine devcontainerCLIJSONLogLine
+		if err := json.Unmarshal(line, &logLine); err != nil {
+			l.logger.Error(l.ctx, "parse devcontainer json log line failed", slog.Error(err), slog.F("line", string(line)))
+			continue
+		}
+		if logLine.Level >= 3 {
+			l.logger.Info(l.ctx, "@devcontainer/cli", slog.F("line", string(line)))
+			continue
+		}
+		l.logger.Debug(l.ctx, "@devcontainer/cli", slog.F("line", string(line)))
+	}
+	if err := s.Err(); err != nil {
+		l.logger.Error(l.ctx, "devcontainer log line scan failed", slog.Error(err))
+	}
+	return len(p), nil
+}