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internal_workflow.go
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internal_workflow.go
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// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package cadence
// All code in this file is private to the package.
import (
"errors"
"fmt"
"reflect"
"runtime"
"strings"
"sync"
"time"
"unicode"
"go.uber.org/cadence/.gen/go/shared"
"go.uber.org/cadence/common"
"go.uber.org/zap"
)
const (
defaultSignalChannelSize = 100000 // really large buffering size(100K)
)
type (
syncWorkflowDefinition struct {
workflow workflow
dispatcher dispatcher
cancel CancelFunc
cancelRequested bool
rootCtx Context
}
workflowResult struct {
workflowResult []byte
error error
}
activityClient struct {
dispatcher dispatcher
asyncClient asyncActivityClient
}
futureImpl struct {
value interface{}
err error
ready bool
channel *channelImpl
chained []asyncFuture // Futures that are chained to this one
}
// Dispatcher is a container of a set of coroutines.
dispatcher interface {
// ExecuteUntilAllBlocked executes coroutines one by one in deterministic order
// until all of them are completed or blocked on Channel or Selector
ExecuteUntilAllBlocked() (err PanicError)
// IsDone returns true when all of coroutines are completed
IsDone() bool
Close() // Destroys all coroutines without waiting for their completion
StackTrace() string // Stack trace of all coroutines owned by the Dispatcher instance
}
// Workflow is an interface that any workflow should implement.
// Code of a workflow must be deterministic. It must use cadence.Channel, cadence.Selector, and cadence.Go instead of
// native channels, select and go. It also must not use range operation over map as it is randomized by go runtime.
// All time manipulation should use current time returned by GetTime(ctx) method.
// Note that cadence.Context is used instead of context.Context to avoid use of raw channels.
workflow interface {
Execute(ctx Context, input []byte) (result []byte, err error)
}
valueCallbackPair struct {
value interface{}
callback func() bool // false indicates that callback didn't accept the value
}
// false result means that callback didn't accept the value and it is still up for delivery
receiveCallback func(v interface{}, more bool) bool
channelImpl struct {
name string // human readable channel name
size int // Channel buffer size. 0 for non buffered.
buffer []interface{} // buffered messages
blockedSends []valueCallbackPair // puts waiting when buffer is full.
blockedReceives []receiveCallback // receives waiting when no messages are available.
closed bool // true if channel is closed.
recValue *interface{} // Used only while receiving value, this is used as pre-fetch buffer value from the channel.
}
// Single case statement of the Select
selectCase struct {
channel *channelImpl // Channel of this case.
receiveFunc *func(c Channel, more bool) // function to call when channel has a message. nil for send case.
sendFunc *func() // function to call when channel accepted a message. nil for receive case.
sendValue *interface{} // value to send to the channel. Used only for send case.
future asyncFuture // Used for future case
futureFunc *func(f Future) // function to call when Future is ready
}
// Implements Selector interface
selectorImpl struct {
name string
cases []*selectCase // cases that this select is comprised from
defaultFunc *func() // default case
}
// unblockFunc is passed evaluated by a coroutine yield. When it returns false the yield returns to a caller.
// stackDepth is the depth of stack from the last blocking call relevant to user.
// Used to truncate internal stack frames from thread stack.
unblockFunc func(status string, stackDepth int) (keepBlocked bool)
coroutineState struct {
name string
dispatcher *dispatcherImpl // dispatcher this context belongs to
aboutToBlock chan bool // used to notify dispatcher that coroutine that owns this context is about to block
unblock chan unblockFunc // used to notify coroutine that it should continue executing.
keptBlocked bool // true indicates that coroutine didn't make any progress since the last yield unblocking
closed bool // indicates that owning coroutine has finished execution
panicError PanicError // non nil if coroutine had unhandled panic
}
dispatcherImpl struct {
sequence int
channelSequence int // used to name channels
selectorSequence int // used to name channels
coroutines []*coroutineState
executing bool // currently running ExecuteUntilAllBlocked. Used to avoid recursive calls to it.
mutex sync.Mutex // used to synchronize executing
closed bool
}
workflowOptions struct {
workflowType *WorkflowType
input []byte
taskListName *string
executionStartToCloseTimeoutSeconds *int32
taskStartToCloseTimeoutSeconds *int32
domain *string
workflowID string
childPolicy ChildWorkflowPolicy
waitForCancellation bool
signalChannels map[string]Channel
}
// decodeFutureImpl
decodeFutureImpl struct {
*futureImpl
fn interface{}
}
childWorkflowFutureImpl struct {
*decodeFutureImpl // for child workflow result
executionFuture *futureImpl // for child workflow execution future
}
asyncFuture interface {
Future
// Used by selectorImpl
// If Future is ready returns its value immediately.
// If not registers callback which is called when it is ready.
GetAsync(callback receiveCallback) (v interface{}, ok bool, err error)
// This future will added to list of dependency futures.
ChainFuture(f Future)
// Gets the current value and error.
// Make sure this is called once the future is ready.
GetValueAndError() (v interface{}, err error)
Set(value interface{}, err error)
}
)
const (
workflowEnvironmentContextKey = "workflowEnv"
workflowResultContextKey = "workflowResult"
coroutinesContextKey = "coroutines"
workflowEnvOptionsContextKey = "wfEnvOptions"
)
// Assert that structs do indeed implement the interfaces
var _ Channel = (*channelImpl)(nil)
var _ Selector = (*selectorImpl)(nil)
var _ dispatcher = (*dispatcherImpl)(nil)
var stackBuf [100000]byte
// Pointer to pointer to workflow result
func getWorkflowResultPointerPointer(ctx Context) **workflowResult {
rpp := ctx.Value(workflowResultContextKey)
if rpp == nil {
panic("getWorkflowResultPointerPointer: Not a workflow context")
}
return rpp.(**workflowResult)
}
func getWorkflowEnvironment(ctx Context) workflowEnvironment {
wc := ctx.Value(workflowEnvironmentContextKey)
if wc == nil {
panic("getWorkflowContext: Not a workflow context")
}
return wc.(workflowEnvironment)
}
func (f *futureImpl) Get(ctx Context, value interface{}) error {
more := f.channel.Receive(ctx, nil)
if more {
panic("not closed")
}
if !f.ready {
panic("not ready")
}
if f.err != nil || f.value == nil || value == nil {
return f.err
}
rf := reflect.ValueOf(value)
if rf.Type().Kind() != reflect.Ptr {
return errors.New("value parameter is not a pointer")
}
fv := reflect.ValueOf(f.value)
if fv.IsValid() {
rf.Elem().Set(fv)
}
return f.err
}
// Used by selectorImpl
// If Future is ready returns its value immediately.
// If not registers callback which is called when it is ready.
func (f *futureImpl) GetAsync(callback receiveCallback) (v interface{}, ok bool, err error) {
_, _, more := f.channel.receiveAsyncImpl(callback)
// Future uses Channel.Close to indicate that it is ready.
// So more being true (channel is still open) indicates future is not ready.
if more {
return nil, false, nil
}
if !f.ready {
panic("not ready")
}
return f.value, true, f.err
}
func (f *futureImpl) IsReady() bool {
return f.ready
}
func (f *futureImpl) Set(value interface{}, err error) {
if f.ready {
panic("already set")
}
f.value = value
f.err = err
f.ready = true
f.channel.Close()
for _, ch := range f.chained {
ch.Set(f.value, f.err)
}
}
func (f *futureImpl) SetValue(value interface{}) {
if f.ready {
panic("already set")
}
f.Set(value, nil)
}
func (f *futureImpl) SetError(err error) {
if f.ready {
panic("already set")
}
f.Set(nil, err)
}
func (f *futureImpl) Chain(future Future) {
if f.ready {
panic("already set")
}
ch, ok := future.(asyncFuture)
if !ok {
panic("cannot chain Future that wasn't created with cadence.NewFuture")
}
if !ch.IsReady() {
ch.ChainFuture(f)
return
}
val, err := ch.GetValueAndError()
f.value = val
f.err = err
f.ready = true
return
}
func (f *futureImpl) ChainFuture(future Future) {
f.chained = append(f.chained, future.(asyncFuture))
}
func (f *futureImpl) GetValueAndError() (interface{}, error) {
return f.value, f.err
}
func (f childWorkflowFutureImpl) GetChildWorkflowExecution() Future {
return f.executionFuture
}
func (d *syncWorkflowDefinition) Execute(env workflowEnvironment, input []byte) {
d.rootCtx = WithValue(background, workflowEnvironmentContextKey, env)
var resultPtr *workflowResult
d.rootCtx = WithValue(d.rootCtx, workflowResultContextKey, &resultPtr)
// Set default values for the workflow execution.
wInfo := env.WorkflowInfo()
d.rootCtx = WithWorkflowDomain(d.rootCtx, wInfo.Domain)
d.rootCtx = WithWorkflowTaskList(d.rootCtx, wInfo.TaskListName)
d.rootCtx = WithExecutionStartToCloseTimeout(d.rootCtx, time.Duration(wInfo.ExecutionStartToCloseTimeoutSeconds)*time.Second)
d.rootCtx = WithWorkflowTaskStartToCloseTimeout(d.rootCtx, time.Duration(wInfo.TaskStartToCloseTimeoutSeconds)*time.Second)
d.rootCtx = WithTaskList(d.rootCtx, wInfo.TaskListName)
activityOptions := getActivityOptions(d.rootCtx)
activityOptions.OriginalTaskListName = wInfo.TaskListName
d.dispatcher = newDispatcher(d.rootCtx, func(ctx Context) {
d.rootCtx, d.cancel = WithCancel(ctx)
r := &workflowResult{}
// We want to execute the user workflow definition from the first decision task started,
// so they can see everything before that. Here we would have all initialization done, hence
// we are yielding.
state := getState(d.rootCtx)
state.yield("yield before executing to setup state")
r.workflowResult, r.error = d.workflow.Execute(d.rootCtx, input)
rpp := getWorkflowResultPointerPointer(ctx)
*rpp = r
})
getWorkflowEnvironment(d.rootCtx).RegisterCancelHandler(func() {
// It is ok to call this method multiple times.
// it doesn't do anything new, the context remains cancelled.
d.cancel()
})
getWorkflowEnvironment(d.rootCtx).RegisterSignalHandler(func(name string, result []byte) {
eo := getWorkflowEnvOptions(d.rootCtx)
// We don't want this code to be blocked ever, using sendAsync().
ch := eo.getSignalChannel(d.rootCtx, name).(*channelImpl)
ok := ch.SendAsync(result)
if !ok {
panic(fmt.Sprintf("Exceeded channel buffer size for signal: %v", name))
}
})
// There is a inter dependency, before we call Execute() we can have a cancel request since
// dispatcher executes code on decision task started, we might not have cancel handler created.
// (1) WithCancel -> creates channel -> needs dispatcher -> dispatcher needs a root function with context.
// (2) Signals before first decision start needs to setup channels with data and needs the context with co-routine state.
// (3) ...
// So all the events, that need to be executed before first decision task need a context with with co-routine state
// setup. So we call execute here so we get the root context created.
executeDispatcher(d.rootCtx, d.dispatcher)
}
func (d *syncWorkflowDefinition) OnDecisionTaskStarted() {
executeDispatcher(d.rootCtx, d.dispatcher)
}
func (d *syncWorkflowDefinition) StackTrace() string {
return d.dispatcher.StackTrace()
}
func (d *syncWorkflowDefinition) Close() {
if d.dispatcher != nil {
d.dispatcher.Close()
}
}
// NewDispatcher creates a new Dispatcher instance with a root coroutine function.
// Context passed to the root function is child of the passed rootCtx.
// This way rootCtx can be used to pass values to the coroutine code.
func newDispatcher(rootCtx Context, root func(ctx Context)) dispatcher {
result := &dispatcherImpl{}
result.newCoroutine(rootCtx, root)
return result
}
// getDispatcher retrieves current dispatcher from the Context passed to the coroutine function.
func getDispatcher(ctx Context) dispatcher {
return getState(ctx).dispatcher
}
// executeDispatcher executed coroutines in the calling thread and calls workflow completion callbacks
// if root workflow function returned
func executeDispatcher(ctx Context, dispatcher dispatcher) {
checkUnhandledSigFn := func(ctx Context) {
us := getWorkflowEnvOptions(ctx).getUnhandledSignals()
if len(us) > 0 {
getWorkflowEnvironment(ctx).GetLogger().Warn("Workflow has unhandled signals",
zap.Strings("SignalNames", us))
// TODO: We don't have a metrics added to workflow environment yet,
// this need to be reported as a metric.
}
}
panicErr := dispatcher.ExecuteUntilAllBlocked()
if panicErr != nil {
env := getWorkflowEnvironment(ctx)
env.GetLogger().Error("Dispatcher panic.",
zap.String("PanicError", panicErr.Error()),
zap.String("PanicStack", panicErr.StackTrace()))
checkUnhandledSigFn(ctx)
env.Complete(nil, NewErrorWithDetails(panicErr.Error(), []byte(panicErr.StackTrace())))
return
}
rp := *getWorkflowResultPointerPointer(ctx)
if rp == nil {
// Result is not set, so workflow is still executing
return
}
checkUnhandledSigFn(ctx)
getWorkflowEnvironment(ctx).Complete(rp.workflowResult, rp.error)
}
// For troubleshooting stack pretty printing only.
// Set to true to see full stack trace that includes framework methods.
const disableCleanStackTraces = false
func getState(ctx Context) *coroutineState {
s := ctx.Value(coroutinesContextKey)
if s == nil {
panic("getState: not workflow context")
}
return s.(*coroutineState)
}
func (c *channelImpl) Receive(ctx Context, valuePtr interface{}) (more bool) {
state := getState(ctx)
hasResult := false
var result interface{}
callback := func(v interface{}, m bool) bool {
result = v
hasResult = true
more = m
return true
}
v, ok, more := c.receiveAsyncImpl(callback)
if ok || !more {
c.assignValue(v, valuePtr)
return more
}
for {
if hasResult {
state.unblocked()
c.assignValue(result, valuePtr)
return more
}
state.yield(fmt.Sprintf("blocked on %s.Receive", c.name))
}
}
func (c *channelImpl) ReceiveAsync(valuePtr interface{}) (ok bool) {
ok, _ = c.ReceiveAsyncWithMoreFlag(valuePtr)
return ok
}
func (c *channelImpl) ReceiveAsyncWithMoreFlag(valuePtr interface{}) (ok bool, more bool) {
v, ok, more := c.receiveAsyncImpl(nil)
c.assignValue(v, valuePtr)
return ok, more
}
// ok = true means that value was received
// more = true means that channel is not closed and more deliveries are possible
func (c *channelImpl) receiveAsyncImpl(callback receiveCallback) (v interface{}, ok bool, more bool) {
if c.recValue != nil {
r := *c.recValue
c.recValue = nil
return r, true, true
}
if len(c.buffer) > 0 {
r := c.buffer[0]
c.buffer = c.buffer[1:]
return r, true, true
}
if c.closed {
return nil, false, false
}
for len(c.blockedSends) > 0 {
b := c.blockedSends[0]
c.blockedSends = c.blockedSends[1:]
if b.callback() {
return b.value, true, true
}
}
if callback != nil {
c.blockedReceives = append(c.blockedReceives, callback)
}
return nil, false, true
}
func (c *channelImpl) Send(ctx Context, v interface{}) {
state := getState(ctx)
valueConsumed := false
pair := &valueCallbackPair{
value: v,
callback: func() bool {
valueConsumed = true
return true
},
}
ok := c.sendAsyncImpl(v, pair)
if ok {
state.unblocked()
return
}
for {
// Check for closed in the loop as close can be called when send is blocked
if c.closed {
panic("Closed channel")
}
if valueConsumed {
state.unblocked()
return
}
state.yield(fmt.Sprintf("blocked on %s.Send", c.name))
}
}
func (c *channelImpl) SendAsync(v interface{}) (ok bool) {
return c.sendAsyncImpl(v, nil)
}
func (c *channelImpl) sendAsyncImpl(v interface{}, pair *valueCallbackPair) (ok bool) {
if c.closed {
panic("Closed channel")
}
for len(c.blockedReceives) > 0 {
blockedGet := c.blockedReceives[0]
c.blockedReceives = c.blockedReceives[1:]
// false from callback indicates that value wasn't consumed
if blockedGet(v, true) {
return true
}
}
if len(c.buffer) < c.size {
c.buffer = append(c.buffer, v)
return true
}
if pair != nil {
c.blockedSends = append(c.blockedSends, *pair)
}
return false
}
func (c *channelImpl) Close() {
c.closed = true
for i := 0; i < len(c.blockedReceives); i++ {
callback := c.blockedReceives[i]
callback(nil, false)
}
// All blocked sends are going to panic
for i := 0; i < len(c.blockedSends); i++ {
b := c.blockedSends[i]
b.callback()
}
}
// Takes a value and assigns that 'to' value.
func (c *channelImpl) assignValue(from interface{}, to interface{}) {
err := decodeAndAssignValue(from, to)
if err != nil {
panic(err)
}
}
// initialYield called at the beginning of the coroutine execution
// stackDepth is the depth of top of the stack to omit when stack trace is generated
// to hide frames internal to the framework.
func (s *coroutineState) initialYield(stackDepth int, status string) {
keepBlocked := true
for keepBlocked {
f := <-s.unblock
keepBlocked = f(status, stackDepth+1)
}
}
// yield indicates that coroutine cannot make progress and should sleep
// this call blocks
func (s *coroutineState) yield(status string) {
s.aboutToBlock <- true
s.initialYield(3, status) // omit three levels of stack. To adjust change to 0 and count the lines to remove.
s.keptBlocked = true
}
func getStackTrace(coroutineName, status string, stackDepth int) string {
top := fmt.Sprintf("coroutine %s [%s]:", coroutineName, status)
// Omit top stackDepth frames + top status line.
// Omit bottom two frames which is wrapping of coroutine in a goroutine.
return getStackTraceRaw(top, stackDepth*2+1, 4)
}
func getStackTraceRaw(top string, omitTop, omitBottom int) string {
stack := stackBuf[:runtime.Stack(stackBuf[:], false)]
rawStack := fmt.Sprintf("%s", strings.TrimRightFunc(string(stack), unicode.IsSpace))
if disableCleanStackTraces {
return rawStack
}
lines := strings.Split(rawStack, "\n")
lines = lines[omitTop : len(lines)-omitBottom]
lines = append([]string{top}, lines...)
return strings.Join(lines, "\n")
}
// unblocked is called by coroutine to indicate that since the last time yield was unblocked channel or select
// where unblocked versus calling yield again after checking their condition
func (s *coroutineState) unblocked() {
s.keptBlocked = false
}
func (s *coroutineState) call() {
s.unblock <- func(status string, stackDepth int) bool {
return false // unblock
}
<-s.aboutToBlock
}
func (s *coroutineState) close() {
s.closed = true
s.aboutToBlock <- true
}
func (s *coroutineState) exit() {
if !s.closed {
s.unblock <- func(status string, stackDepth int) bool {
runtime.Goexit()
return true
}
}
}
func (s *coroutineState) stackTrace() string {
if s.closed {
return ""
}
stackCh := make(chan string, 1)
s.unblock <- func(status string, stackDepth int) bool {
stackCh <- getStackTrace(s.name, status, stackDepth+2)
return true
}
return <-stackCh
}
func (s *coroutineState) NewCoroutine(ctx Context, f func(ctx Context)) {
s.dispatcher.newCoroutine(ctx, f)
}
func (s *coroutineState) NewNamedCoroutine(ctx Context, name string, f func(ctx Context)) {
s.dispatcher.newNamedCoroutine(ctx, name, f)
}
func (s *coroutineState) NewSelector() Selector {
s.dispatcher.selectorSequence++
return s.NewNamedSelector(fmt.Sprintf("selector-%v", s.dispatcher.selectorSequence))
}
func (s *coroutineState) NewNamedSelector(name string) Selector {
return &selectorImpl{name: name}
}
func (s *coroutineState) NewChannel() Channel {
s.dispatcher.channelSequence++
return s.NewNamedChannel(fmt.Sprintf("chan-%v", s.dispatcher.channelSequence))
}
func (s *coroutineState) NewNamedChannel(name string) Channel {
return &channelImpl{name: name}
}
func (s *coroutineState) NewBufferedChannel(size int) Channel {
return &channelImpl{size: size}
}
func (s *coroutineState) NewNamedBufferedChannel(name string, size int) Channel {
return &channelImpl{name: name, size: size}
}
func (d *dispatcherImpl) newCoroutine(ctx Context, f func(ctx Context)) {
d.newNamedCoroutine(ctx, fmt.Sprintf("%v", d.sequence+1), f)
}
func (d *dispatcherImpl) newNamedCoroutine(ctx Context, name string, f func(ctx Context)) {
state := d.newState(name)
spawned := WithValue(ctx, coroutinesContextKey, state)
go func(crt *coroutineState) {
defer crt.close()
defer func() {
if r := recover(); r != nil {
st := getStackTrace(name, "panic", 4)
crt.panicError = newPanicError(r, st)
}
}()
crt.initialYield(1, "")
f(spawned)
}(state)
}
func (d *dispatcherImpl) newState(name string) *coroutineState {
c := &coroutineState{
name: name,
dispatcher: d,
aboutToBlock: make(chan bool, 1),
unblock: make(chan unblockFunc),
}
d.sequence++
d.coroutines = append(d.coroutines, c)
return c
}
func (d *dispatcherImpl) ExecuteUntilAllBlocked() (err PanicError) {
d.mutex.Lock()
if d.closed {
panic("dispatcher is closed")
}
if d.executing {
panic("call to ExecuteUntilAllBlocked (possibly from a coroutine) while it is already running")
}
d.executing = true
d.mutex.Unlock()
defer func() { d.executing = false }()
allBlocked := false
// Keep executing until at least one goroutine made some progress
for !allBlocked {
// Give every coroutine chance to execute removing closed ones
allBlocked = true
lastSequence := d.sequence
for i := 0; i < len(d.coroutines); i++ {
c := d.coroutines[i]
if !c.closed {
// TODO: Support handling of panic in a coroutine by dispatcher.
// TODO: Dump all outstanding coroutines if one of them panics
c.call()
}
// c.call() can close the context so check again
if c.closed {
// remove the closed one from the slice
d.coroutines = append(d.coroutines[:i],
d.coroutines[i+1:]...)
i--
if c.panicError != nil {
return c.panicError
}
allBlocked = false
} else {
allBlocked = allBlocked && (c.keptBlocked || c.closed)
}
}
// Set allBlocked to false if new coroutines where created
allBlocked = allBlocked && lastSequence == d.sequence
if len(d.coroutines) == 0 {
break
}
}
return nil
}
func (d *dispatcherImpl) IsDone() bool {
return len(d.coroutines) == 0
}
func (d *dispatcherImpl) Close() {
d.mutex.Lock()
if d.closed {
d.mutex.Unlock()
return
}
d.closed = true
d.mutex.Unlock()
for i := 0; i < len(d.coroutines); i++ {
c := d.coroutines[i]
if !c.closed {
c.exit()
}
}
}
func (d *dispatcherImpl) StackTrace() string {
var result string
for i := 0; i < len(d.coroutines); i++ {
c := d.coroutines[i]
if !c.closed {
if len(result) > 0 {
result += "\n\n"
}
result += c.stackTrace()
}
}
return result
}
func (s *selectorImpl) AddReceive(c Channel, f func(c Channel, more bool)) Selector {
s.cases = append(s.cases, &selectCase{channel: c.(*channelImpl), receiveFunc: &f})
return s
}
func (s *selectorImpl) AddSend(c Channel, v interface{}, f func()) Selector {
s.cases = append(s.cases, &selectCase{channel: c.(*channelImpl), sendFunc: &f, sendValue: &v})
return s
}
func (s *selectorImpl) AddFuture(future Future, f func(future Future)) Selector {
asyncF, ok := future.(asyncFuture)
if !ok {
panic("cannot chain Future that wasn't created with cadence.NewFuture")
}
s.cases = append(s.cases, &selectCase{future: asyncF, futureFunc: &f})
return s
}
func (s *selectorImpl) AddDefault(f func()) {
s.defaultFunc = &f
}
func (s *selectorImpl) Select(ctx Context) {
state := getState(ctx)
var readyBranch func()
for _, pair := range s.cases {
if pair.receiveFunc != nil {
f := *pair.receiveFunc
c := pair.channel
callback := func(v interface{}, more bool) bool {
if readyBranch != nil {
return false
}
readyBranch = func() {
c.recValue = &v
f(c, more)
}
return true
}
v, ok, more := pair.channel.receiveAsyncImpl(callback)
if ok || !more {
c.recValue = &v
f(c, more)
return
}
} else if pair.sendFunc != nil {
f := *pair.sendFunc
p := &valueCallbackPair{
value: *pair.sendValue,
callback: func() bool {
if readyBranch != nil {
return false
}
readyBranch = func() {
f()
}
return true
},
}
ok := pair.channel.sendAsyncImpl(*pair.sendValue, p)
if ok {
f()
return
}
} else if pair.futureFunc != nil {
p := pair
f := *p.futureFunc
callback := func(v interface{}, more bool) bool {
if readyBranch != nil {
return false
}
p.futureFunc = nil
readyBranch = func() {
f(p.future)
}
return true
}
_, ok, _ := p.future.GetAsync(callback)
if ok {
p.futureFunc = nil
f(p.future)
return
}
}
}
if s.defaultFunc != nil {
f := *s.defaultFunc
f()
return
}
for {
if readyBranch != nil {
readyBranch()
state.unblocked()
return
}
state.yield(fmt.Sprintf("blocked on %s.Select", s.name))
}
}
// NewWorkflowDefinition creates a WorkflowDefinition from a Workflow
func newWorkflowDefinition(workflow workflow) workflowDefinition {
return &syncWorkflowDefinition{workflow: workflow}
}
func getValidatedWorkerFunction(workflowFunc interface{}, args []interface{}) (*WorkflowType, []byte, error) {
fnName := ""
fType := reflect.TypeOf(workflowFunc)
switch fType.Kind() {
case reflect.String:
fnName = reflect.ValueOf(workflowFunc).String()
case reflect.Func:
if err := validateFunctionArgs(workflowFunc, args, true); err != nil {
return nil, nil, err
}
fnName = getFunctionName(workflowFunc)
default:
return nil, nil, fmt.Errorf(
"Invalid type 'workflowFunc' parameter provided, it can be either worker function or name of the worker type: %v",
workflowFunc)
}
input, err := getHostEnvironment().encodeArgs(args)
if err != nil {
return nil, nil, err
}
return &WorkflowType{Name: fnName}, input, nil
}
func getValidatedWorkflowOptions(ctx Context) (*workflowOptions, error) {
p := getWorkflowEnvOptions(ctx)
if p == nil {
// We need task list as a compulsory parameter. This can be removed after registration
return nil, errWorkflowOptionBadRequest
}
info := GetWorkflowInfo(ctx)
if p.domain == nil || *p.domain == "" {
// default to use current workflow's domain
p.domain = common.StringPtr(info.Domain)
}
if p.taskListName == nil || *p.taskListName == "" {
// default to use current workflow's task list
p.taskListName = common.StringPtr(info.TaskListName)
}
if p.taskStartToCloseTimeoutSeconds == nil || *p.taskStartToCloseTimeoutSeconds < 0 {
return nil, errors.New("missing or negative StartToCloseTimeoutSeconds")
}
if *p.taskStartToCloseTimeoutSeconds == 0 {
p.taskStartToCloseTimeoutSeconds = common.Int32Ptr(10) // default to 10s for decision task timeout
}
if p.executionStartToCloseTimeoutSeconds == nil || *p.executionStartToCloseTimeoutSeconds <= 0 {
return nil, errors.New("missing or invalid ExecutionStartToCloseTimeoutSeconds")
}
return p, nil
}
func getWorkflowEnvOptions(ctx Context) *workflowOptions {
options := ctx.Value(workflowEnvOptionsContextKey)
if options != nil {
return options.(*workflowOptions)
}
return nil
}
func setWorkflowEnvOptionsIfNotExist(ctx Context) Context {
if valCtx := getWorkflowEnvOptions(ctx); valCtx == nil {
return WithValue(ctx, workflowEnvOptionsContextKey, &workflowOptions{
signalChannels: make(map[string]Channel)})
}
return ctx
}
// getSignalChannel finds the assosciated channel for the signal.
func (w *workflowOptions) getSignalChannel(ctx Context, signalName string) Channel {
if ch, ok := w.signalChannels[signalName]; ok {
return ch
}
ch := NewBufferedChannel(ctx, defaultSignalChannelSize)