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stateful.go
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stateful.go
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// Copyright 2022 Namespace Labs Inc; All rights reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
package tasks
import (
"context"
"io"
"sync"
"namespacelabs.dev/foundation/internal/console/common"
"namespacelabs.dev/foundation/std/tasks/protocol"
)
// Keeps track of which actions are running, and have run in the past.
type statefulState struct {
parent ActionSink
keepHistory bool
mu sync.Mutex
running []*RunningAction
observers []Observer
allTasks []*protocol.Task
protoIndex map[ActionID]int
allAttachments map[ActionID]*EventAttachments
}
type Observer interface {
OnStart(*RunningAction)
OnUpdate(*RunningAction)
OnDone(*RunningAction)
}
type StatefulSink struct{ state *statefulState }
var _ ActionSink = &statefulState{}
func NewStatefulSink(parent ActionSink, keepHistory bool) *StatefulSink {
return &StatefulSink{&statefulState{
parent: parent,
protoIndex: map[ActionID]int{},
allAttachments: map[ActionID]*EventAttachments{},
keepHistory: keepHistory,
}}
}
func WithStatefulSink(ctx context.Context) (context.Context, *StatefulSink) {
state := NewStatefulSink(SinkFrom(ctx), true)
return WithSink(ctx, state.Sink()), state
}
func (s *StatefulSink) Sink() ActionSink { return s.state }
func (s *StatefulSink) HistoricReaderByName(id ActionID, name string) io.ReadCloser {
s.state.mu.Lock()
defer s.state.mu.Unlock()
if attachments, ok := s.state.allAttachments[id]; ok {
return attachments.ReaderByName(name)
}
return nil
}
func (s *StatefulSink) History(max int, filter func(*protocol.Task) bool) []*protocol.Task {
s.state.mu.Lock()
defer s.state.mu.Unlock()
var filtered []*protocol.Task
for _, t := range s.state.allTasks {
if filter == nil || filter(t) {
filtered = append(filtered, t)
}
}
start := 0
if len(filtered) > max {
start = len(filtered) - max
}
history := filtered[start:]
return history
}
// Recursively returns the action and all of its callers (leaf action first).
func (s *StatefulSink) Trace(id ActionID) (trace []*protocol.Task) {
// XXX: the implementation is rather inefficient.
next := s.state.runningAction(id)
for next != nil {
trace = append(trace, next.Data.Proto())
if next.Data.ParentID != "" {
next = s.state.runningAction(next.Data.ParentID)
} else {
next = s.state.waitingAction(next.Data.ActionID)
// next=nil when there is no waiting action.
}
}
return
}
func (s *StatefulSink) Observe(obs Observer) func() {
s.state.mu.Lock()
s.state.observers = append(s.state.observers, obs)
s.state.mu.Unlock()
return func() {
s.state.mu.Lock()
defer s.state.mu.Unlock()
for k, was := range s.state.observers {
if was == obs {
s.state.observers = append(s.state.observers[0:k], s.state.observers[k+1:]...)
return
}
}
}
}
func (s *statefulState) runningAction(id ActionID) *RunningAction {
for _, a := range s.running {
if a.ID() == id {
return a
}
}
return nil
}
func (s *statefulState) waitingAction(id ActionID) *RunningAction {
for _, a := range s.running {
if a.Data.AnchorID == id {
return a
}
}
return nil
}
func (s *statefulState) addToRunning(ra *RunningAction) []Observer {
p := ra.Proto()
s.mu.Lock()
if _, ok := s.protoIndex[ra.Data.ActionID]; !ok {
s.running = append(s.running, ra)
if s.keepHistory {
s.allAttachments[ra.Data.ActionID] = ra.attachments
index := len(s.allTasks)
s.allTasks = append(s.allTasks, p)
s.protoIndex[ra.Data.ActionID] = index
}
}
observers := s.observers
s.mu.Unlock()
return observers
}
func (s *statefulState) Waiting(ra *RunningAction) {
if s.parent != nil {
s.parent.Waiting(ra)
}
s.addToRunning(ra)
}
func (s *statefulState) Started(ra *RunningAction) {
if s.parent != nil {
s.parent.Started(ra)
}
observers := s.addToRunning(ra)
for _, obs := range observers {
obs.OnStart(ra)
}
}
func (s *statefulState) removeFromRunning(ra *RunningAction) {
p := ra.Proto()
s.mu.Lock()
observers := s.observers
for k, running := range s.running {
if running.ID() == ra.ID() {
s.running = append(s.running[0:k], s.running[k+1:]...)
break
}
}
if index, ok := s.protoIndex[ra.Data.ActionID]; ok {
s.allTasks[index] = p // Update with completed, etc.
}
s.mu.Unlock()
for _, obs := range observers {
obs.OnDone(ra)
}
}
func (s *statefulState) Done(ra *RunningAction) {
if s.parent != nil {
s.parent.Done(ra)
}
s.removeFromRunning(ra)
}
func (s *statefulState) Instant(ev *EventData) {
if s.parent != nil {
s.parent.Instant(ev)
}
}
func (s *statefulState) AttachmentsUpdated(actionID ActionID, data *ResultData) {
if s.parent != nil {
s.parent.AttachmentsUpdated(actionID, data)
}
s.mu.Lock()
observers := s.observers
var r *RunningAction
for _, running := range s.running {
if running.ID() == actionID {
r = running
break
}
}
if r != nil {
p := r.Proto()
if index, ok := s.protoIndex[actionID]; ok {
s.allTasks[index] = p
}
}
s.mu.Unlock()
if r != nil {
for _, obs := range observers {
obs.OnUpdate(r)
}
}
}
func (s *statefulState) Output(name, contentType string, outputType common.CatOutputType) io.Writer {
return nil
}
func (s *statefulState) Unwrap() ActionSink {
return s.parent
}