import (
"context"
+ "encoding/json"
"errors"
"fmt"
+ "log/slog"
+ "maps"
"os"
+ "path/filepath"
"slices"
"strings"
"sync"
+ "time"
)
const (
// subagentNoteEffort follows subagentNote when the subagent has its own
// effort.
subagentNoteEffort = " at effort "
+
+ // subagentWorkFileName is the file of the names of the running
+ // subagents in the directory of an agent.
+ subagentWorkFileName = "work.json"
)
// The statuses of the end of a run, in the work event of its report.
// of the subagent. A message of Tell that comes during a chain joins its next
// request after the tool results. One that comes after the final answer starts
// one more chain, which reads the log again. The report of the run goes to
-// report: the final answer of each chain, or the error of a failed call. Stop
-// ends one run, and its report says that it stopped. At the stop of the daemon
-// the runs end with no report.
+// report: the final answer of each chain, or the error of a failed call. The
+// logger gets one line at the end of a run: done, failed with the cause, or
+// stopped. Stop ends one run, and its report says that it stopped. At the stop
+// of the daemon the runs end with no report.
+//
+// work.json in the directory of the agent holds the names of the running
+// subagents. Each start and each end of a run writes it whole, but Close does
+// not, so after a stop of the daemon it names the runs that the stop cut, and
+// Resume goes on with them. The logs alone cannot tell this, because a stop
+// can cut a run just after its final reply.
//
// Spawn and Tell split the view with the layout of the agent, which has no
// lock. They are tools, so they run in the goroutine of the turns, as each
state func() string
report func(name, text, status string)
note func(text string) error
+ fail func(err error)
+ logger *slog.Logger
notify func(Event)
mutex sync.Mutex
}
r.mutex.Lock()
+
closed := r.closed
r.mutex.Unlock()
// its log with a new run, with the view of now and the effort of its note.
func (r *SubagentRuns) Tell(ctx context.Context, name, message string) (string, error) {
r.mutex.Lock()
+
run, found := r.running[name]
if found {
defer r.mutex.Unlock()
return true, nil
}
+// Resume goes on with the runs that a stop of the daemon cut, as work.json
+// names them. The chat gets the note "The daemon restarted, cutting NAMES;
+// nothing was lost: go on.", and each cut subagent gets the same text as a
+// message of Tell. A subagent that cannot go on gets a failed report.
+func (r *SubagentRuns) Resume(ctx context.Context) error {
+ names, err := r.load()
+ if err != nil || len(names) == 0 {
+ return err
+ }
+
+ text := "The daemon restarted, cutting " + strings.Join(names, ", ") + "; nothing was lost: go on."
+ err = r.note(text)
+ if err != nil {
+ return err
+ }
+
+ for _, name := range names {
+ _, err = r.Tell(ctx, name, text)
+ if err != nil {
+ r.logger.Error("subagent lost at restart", "name", name, "err", err)
+ r.report(name, subagentReport(name, []string{"failed: " + err.Error()}), subagentFailed)
+ }
+ }
+
+ // A subagent that cannot go on does not run, so work.json no longer
+ // names it, and the next start does not try it again.
+ r.mutex.Lock()
+ defer r.mutex.Unlock()
+
+ return r.save()
+}
+
// Close ends every run and waits for them. No subagent starts after Close.
func (r *SubagentRuns) Close() {
r.mutex.Lock()
+
r.closed = true
for _, run := range r.running {
run.cancel()
}
+
r.mutex.Unlock()
r.workers.Wait()
return "", fmt.Errorf("the log of %s does not start with a subagent note", subagent.name)
}
-// start runs run in the background. Its context keeps the values of ctx, but
-// only Stop and Close end it.
+// start runs run in the background and logs its start. Its context keeps the
+// values of ctx, but only Stop and Close end it.
func (r *SubagentRuns) start(ctx context.Context, run *SubagentRun) error {
ctx, run.cancel = context.WithCancel(context.WithoutCancel(ctx))
r.mutex.Lock()
+
_, found := r.running[run.subagent.name]
if r.closed || found {
r.mutex.Unlock()
}
r.running[run.subagent.name] = run
+ err := r.save()
+ if err != nil {
+ delete(r.running, run.subagent.name)
+ r.mutex.Unlock()
+ run.cancel()
+
+ return err
+ }
+
r.workers.Add(1)
r.mutex.Unlock()
+ run.started = r.subagents.clock()
+ r.logger.Info("subagent started", "name", run.subagent.name)
r.notify(Event{
Kind: "subagent",
Text: run.subagent.name,
return nil
}
-// run runs the chains of run and reports its end, unless Close ended it. A
-// chain follows while messages wait after the final answer of the chain before
+// load reads the names of work.json. A missing file names none.
+func (r *SubagentRuns) load() ([]string, error) {
+ data, err := os.ReadFile(r.workPath())
+ if errors.Is(err, os.ErrNotExist) {
+ return nil, nil
+ }
+
+ if err != nil {
+ return nil, fmt.Errorf("read running subagents: %w", err)
+ }
+
+ var file SubagentWorkFile
+
+ err = json.Unmarshal(data, &file)
+ if err != nil {
+ return nil, fmt.Errorf("decode running subagents: %w", err)
+ }
+
+ return file.Running, nil
+}
+
+// save writes the names of the running subagents to work.json. The caller
+// holds the mutex.
+func (r *SubagentRuns) save() error {
+ file := SubagentWorkFile{
+ Running: append([]string{}, slices.Sorted(maps.Keys(r.running))...),
+ }
+
+ data, err := json.Marshal(file)
+ if err != nil {
+ return fmt.Errorf("encode running subagents: %w", err)
+ }
+
+ err = writeFileAtomic(r.workPath(), append(data, '\n'))
+ if err != nil {
+ return fmt.Errorf("save running subagents: %w", err)
+ }
+
+ return nil
+}
+
+func (r *SubagentRuns) workPath() string {
+ return filepath.Join(r.agent.dir, subagentWorkFileName)
+}
+
+// run runs the chains of run and reports and logs its end with the length of
+// the run, unless Close ended it. A chain follows while messages wait after the final answer of the chain before
// it, and no chain failed. A chain that Stop ends gives the reply "stopped".
func (r *SubagentRuns) run(ctx context.Context, run *SubagentRun) {
defer r.workers.Done()
defer run.cancel()
- var replies []string
+ var (
+ replies []string
+ failure error
+ )
+
stopped := false
status := subagentFinished
for more := true; more; {
reply, err := r.chain(ctx, run)
r.mutex.Lock()
+
stopped = run.stopped
switch {
case err != nil && stopped:
case err != nil:
reply = "failed: " + err.Error()
status = subagentFailed
+ failure = err
}
more = err == nil && ctx.Err() == nil && len(run.pending) > 0
run.pending = nil
+
+ var saveErr error
+
if !more {
delete(r.running, run.subagent.name)
+
+ if !r.closed {
+ saveErr = r.save()
+ }
}
+
r.mutex.Unlock()
+ if saveErr != nil {
+ r.fail(saveErr)
+ }
+
replies = append(replies, reply)
}
status = subagentStopped
}
+ length := r.subagents.clock().Sub(run.started)
+ switch status {
+ case subagentStopped:
+ r.logger.Info("subagent stopped", "name", run.subagent.name, "after", length)
+ case subagentFailed:
+ r.logger.Error("subagent failed", "name", run.subagent.name, "after", length, "err", failure)
+ default:
+ r.logger.Info("subagent done", "name", run.subagent.name, "after", length)
+ }
+
r.report(run.subagent.name, subagentReport(run.subagent.name, replies), status)
}
// SubagentRun is one run of a subagent: the view that its requests get, its
// effort, the end of its context, the messages of Tell that wait for a request,
-// and whether Stop ended it. The mutex of SubagentRuns protects the messages
+// whether Stop ended it, and the time it started. The mutex of SubagentRuns protects the messages
// and the stop.
type SubagentRun struct {
subagent *Subagent
cancel context.CancelFunc
pending []Message
stopped bool
+ started time.Time
+}
+
+// SubagentWorkFile is the content of work.json.
+type SubagentWorkFile struct {
+ Running []string `json:"running"`
}
// subagentReport returns the report of the subagent name with its replies: the
projects / onechat / blobdiff