flow

package
v1.5.0 Latest Latest
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 Go to latest Published: May 26, 2020 License: Apache-2.0, BSD-2-Clause, MIT, + 1 more Imports: 11 Imported by: 40

Documentation

Overview

Package flow provides utilities to construct a directed acyclic computational graph that is then executed and monitored with maximum parallelism.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ContextWithTimeout is context.WithTimeout. Exposed for testing.
	ContextWithTimeout = context.WithTimeout
)

Functions

func Causes 

func Causes(err error) *multierror.Error

Causes reports the causes of all Task errors of the given Flow error.

func Errors 

func Errors(err error) *multierror.Error

Errors reports all wrapped Task errors of the given Flow error.

func WasCanceled 

func WasCanceled(err error) bool

WasCanceled determines whether the given flow error was caused by cancellation.

Types

type ErrorCleaner 

type ErrorCleaner func(context.Context, string)

ErrorCleaner is called when a task which errored during the previous reconciliation phase completes with success

type Flow 

type Flow struct {
	// contains filtered or unexported fields
}

Flow is a validated executable Graph.

func (*Flow) Len 

func (f *Flow) Len() int

Len retrieves the amount of tasks in a Flow.

func (*Flow) Name 

func (f *Flow) Name() string

Name retrieves the name of a flow.

func (*Flow) Run 

func (f *Flow) Run(opts Opts) error

Run starts an execution of a Flow. It blocks until the Flow has finished and returns the error, if any.

type Graph 

type Graph struct {
	// contains filtered or unexported fields
}

Graph is a builder for a Flow.

func NewGraph 

func NewGraph(name string) *Graph

NewGraph returns a new Graph with the given name.

func (*Graph) Add 

func (g *Graph) Add(task Task) TaskID

Add adds the given Task to the graph. This panics if - There is already a Task present with the same name - One of the dependencies of the Task is not present

func (*Graph) Compile 

func (g *Graph) Compile() *Flow

Compile compiles the graph into an executable Flow.

func (*Graph) Name 

func (g *Graph) Name() string

Name returns the name of a graph.

type Opts 

type Opts struct {
	Logger           logrus.FieldLogger
	ProgressReporter func(ctx context.Context, stats *Stats)
	ErrorCleaner     func(ctx context.Context, taskID string)
	ErrorContext     *utilerrors.ErrorContext
	Context          context.Context
}

Opts are options for a Flow execution. If they are not set, they are left blank and don't affect the Flow.

type ProgressReporter 

type ProgressReporter func(context.Context, *Stats)

ProgressReporter is continuously called on progress in a flow.

type RecoverFn 

type RecoverFn func(ctx context.Context, err error) error

RecoverFn is a function that can recover an error.

type Stats 

type Stats struct {
	All       TaskIDs
	Succeeded TaskIDs
	Failed    TaskIDs
	Running   TaskIDs
	Pending   TaskIDs
}

Stats are the statistics of a Flow execution.

func InitialStats 

func InitialStats(all TaskIDs) *Stats

InitialStats creates a new Stats object with the given set of initial TaskIDs. The initial TaskIDs are added to all TaskIDs as well as to the pending ones.

func (*Stats) Copy 

func (s *Stats) Copy() *Stats

Copy deeply copies a Stats object.

func (*Stats) ProgressPercent 

func (s *Stats) ProgressPercent() int32

ProgressPercent retrieves the progress of a Flow execution in percent.

type Task 

type Task struct {
	Name         string
	Fn           TaskFn
	Dependencies TaskIDs
}

Task is a unit of work. It has a name, a payload function and a set of dependencies. A is only started once all its dependencies have been completed successfully.

func (*Task) Spec 

func (t *Task) Spec() *TaskSpec

Spec returns the TaskSpec of a task.

type TaskFn 

type TaskFn func(ctx context.Context) error

TaskFn is a payload function of a task. 

var EmptyTaskFn TaskFn = func(ctx context.Context) error { return nil }

EmptyTaskFn is a TaskFn that does nothing (returns nil).

func Parallel 

func Parallel(fns ...TaskFn) TaskFn

Parallel runs the given TaskFns in parallel, collecting their errors in a multierror.

func ParallelExitOnError 

func ParallelExitOnError(fns ...TaskFn) TaskFn

ParallelExitOnError runs the given TaskFns in parallel and stops execution as soon as one TaskFn returns an error.

func Sequential 

func Sequential(fns ...TaskFn) TaskFn

Sequential runs the given TaskFns sequentially.

func SimpleTaskFn 

func SimpleTaskFn(f func() error) TaskFn

SimpleTaskFn converts the given function to a TaskFn, disrespecting any context.Context it is being given. deprecated: Only used during transition period. Do not use for new functions.

func (TaskFn) DoIf 

func (t TaskFn) DoIf(condition bool) TaskFn

DoIf returns a TaskFn that will be executed if the condition is true when it is called. Otherwise, it will do nothing when called.

func (TaskFn) Recover 

func (t TaskFn) Recover(recoverFn RecoverFn) TaskFn

Recover creates a new TaskFn that recovers an error with the given RecoverFn.

func (TaskFn) Retry 

func (t TaskFn) Retry(interval time.Duration) TaskFn

Retry returns a TaskFn that is retried until the timeout is reached. Deprecated: Retry handling should be done in the function itself, if necessary.

func (TaskFn) RetryUntilTimeout 

func (t TaskFn) RetryUntilTimeout(interval, timeout time.Duration) TaskFn

RetryUntilTimeout returns a TaskFn that is retried until the timeout is reached.

func (TaskFn) SkipIf 

func (t TaskFn) SkipIf(condition bool) TaskFn

SkipIf returns a TaskFn that does nothing if the condition is true, otherwise the function will be executed once called.

func (TaskFn) Timeout 

func (t TaskFn) Timeout(timeout time.Duration) TaskFn

Timeout returns a TaskFn that is bound to a context which times out.

func (TaskFn) ToRecoverFn 

func (t TaskFn) ToRecoverFn() RecoverFn

ToRecoverFn converts the TaskFn to a RecoverFn that ignores the incoming error.

type TaskID 

type TaskID string

TaskID is an id of a task.

func (TaskID) TaskIDs 

func (t TaskID) TaskIDs() []TaskID

TaskIDs retrieves this TaskID as a singleton slice.

type TaskIDSlice 

type TaskIDSlice []TaskID

TaskIDSlice is a slice of TaskIDs.

func (TaskIDSlice) Len 

func (t TaskIDSlice) Len() int

func (TaskIDSlice) Less 

func (t TaskIDSlice) Less(i1, i2 int) bool

func (TaskIDSlice) Swap 

func (t TaskIDSlice) Swap(i1, i2 int)

func (TaskIDSlice) TaskIDs 

func (t TaskIDSlice) TaskIDs() []TaskID

TaskIDs returns this as a slice of TaskIDs.

type TaskIDer 

type TaskIDer interface {
	// TaskIDs reports all TaskIDs of this TaskIDer.
	TaskIDs() []TaskID
}

TaskIDer can produce a slice of TaskIDs. Default implementations of this are TaskIDs, TaskID and TaskIDSlice

type TaskIDs 

type TaskIDs map[TaskID]struct{}

TaskIDs is a set of TaskID.

func NewTaskIDs 

func NewTaskIDs(ids ...TaskIDer) TaskIDs

NewTaskIDs returns a new set of TaskIDs initialized to contain all TaskIDs of the given TaskIDers.

func (TaskIDs) Copy 

func (t TaskIDs) Copy() TaskIDs

Copy makes a deep copy of this TaskIDs.

func (TaskIDs) Delete 

func (t TaskIDs) Delete(iders ...TaskIDer) TaskIDs

Delete deletes the TaskIDs of all TaskIDers from this TaskIDs.

func (TaskIDs) Has 

func (t TaskIDs) Has(id TaskID) bool

Has checks if the given TaskID is present in this set.

func (TaskIDs) Insert 

func (t TaskIDs) Insert(iders ...TaskIDer) TaskIDs

Insert inserts the TaskIDs of all TaskIDers into this TaskIDs.

func (TaskIDs) InsertIf added in v0.34.0 

func (t TaskIDs) InsertIf(condition bool, iders ...TaskIDer) TaskIDs

InsertIf inserts the TaskIDs of all TaskIDers into this TaskIDs if the given condition evaluates to true.

func (TaskIDs) Len 

func (t TaskIDs) Len() int

Len returns the amount of TaskIDs this contains.

func (TaskIDs) List 

func (t TaskIDs) List() TaskIDSlice

List returns the elements of this in an ordered slice.

func (TaskIDs) StringList 

func (t TaskIDs) StringList() []string

StringList returns the elements of this in an ordered string slice.

func (TaskIDs) TaskIDs 

func (t TaskIDs) TaskIDs() []TaskID

TaskIDs retrieves all TaskIDs as an unsorted slice.

func (TaskIDs) UnsortedList 

func (t TaskIDs) UnsortedList() TaskIDSlice

UnsortedList returns the elements of this in an unordered slice.

func (TaskIDs) UnsortedStringList 

func (t TaskIDs) UnsortedStringList() []string

UnsortedStringList returns the elements of this in an unordered string slice.

type TaskSpec 

type TaskSpec struct {
	Fn           TaskFn
	Dependencies TaskIDs
}

TaskSpec is functional body of a Task, consisting only of the payload function and the dependencies of the Task.

type Tasks 

type Tasks map[TaskID]*TaskSpec

Tasks is a mapping from TaskID to TaskSpec.

Source Files

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