machine

package module
v0.17.4 Latest Latest
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 Go to latest Published: Aug 7, 2021 License: MIT Imports: 20 Imported by: 13

README

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Machine

Machine is a library for creating data workflows. These workflows can be either very concise or quite complex, even allowing for cycles for flows that need retry or self healing mechanisms.

It supports opentelemetry spans and metrics out of the box

It also supports building dynamic pipelines using

Components is a repository of different vertex and plugin implementations

Installation

Add the primary library to your project

  go get -u github.com/whitaker-io/machine

Data is a library for getting and setting values in a map[string]interface{}

Documentation

Gopher

Docs

Example

Basic receive -> process -> send Flow

  stream := NewStream("unique_id1", 
    func(c context.Context) chan []Data {
      channel := make(chan []Data)
    
      // setup channel to collect data as long as 
      // the context has not completed

      return channel
    },
    &Option{FIFO: boolP(false)},
    &Option{Metrics: boolP(true)},
    &Option{Span: boolP(false)},
  )

  stream.Builder().Map("unique_id2", 
      func(m Data) error {
        var err error

        // ...do some processing

        return err
      },
    ).Publish("publish_left_id", publishFN(func(d []data.Data) error {
      // send the data somewhere

      return nil
    }),
  )

  if err := stream.Run(context.Background()); err != nil {
    // Run will return an error in the case that 
    // one of the paths is not terminated (i.e. missing a Publish)
    panic(err)
  }

🤝 Contributing

Contributions, issues and feature requests are welcome.
Feel free to check issues page if you want to contribute.
Check the contributing guide.

Author

👤 Jonathan Whitaker

Show your support

Please ⭐️ this repository if this project helped you!

License

Machine is provided under the MIT License.

The MIT License (MIT)

Copyright (c) 2020 Jonathan Whitaker

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func RegisterPluginProvider added in v0.11.0 

func RegisterPluginProvider(name string, p PluginProvider)

RegisterPluginProvider function for registering a PluginProvider to be used for loading VertexProviders

Types

type Applicative added in v0.3.0 

type Applicative func(d data.Data) error

Applicative is a function that is applied on an individual basis for each Packet in the payload. The data may be modified or checked for correctness. Any resulting error is combined with current errors in the wrapping Packet.

type Builder 

type Builder interface {
	Map(id string, a Applicative) Builder
	FoldLeft(id string, f Fold) Builder
	FoldRight(id string, f Fold) Builder
	Fork(id string, f Fork) (Builder, Builder)
	Loop(id string, x Fork) (loop, out Builder)
	Sort(id string, x Comparator) Builder
	Remove(id string, x Remover) Builder
	Publish(id string, s Publisher)
}

Builder is the interface provided for creating a data processing stream.

type Comparator added in v0.16.5 

type Comparator func(a data.Data, b data.Data) int

Comparator is a function to compare 2 data.Data's

type Edge added in v0.17.0 

type Edge interface {
	Send(ctx context.Context, channel chan []*Packet)
	Next(payload ...*Packet)
}

Edge is an inteface that is used for transferring data between vertices

type EdgeProvider added in v0.17.0 

type EdgeProvider interface {
	New(id string, options *Option) Edge
}

EdgeProvider is an interface that is used for providing new instances of the Edge interface given the *Option set in the Stream

type Error added in v0.16.0 

type Error struct {
	Err        error     `json:"err"`
	StreamID   string    `json:"stream_id"`
	VertexID   string    `json:"vertex_id"`
	VertexType string    `json:"vertex_type"`
	Packets    []*Packet `json:"payload"`
	Time       time.Time `json:"time"`
}

Error type for wrapping errors coming from the Stream

func (*Error) Error added in v0.16.0 

func (e *Error) Error() string

type Fold added in v0.5.0 

type Fold func(aggregate, next data.Data) data.Data

Fold is a function used to combine a payload into a single Packet. It may be used with either a Fold Left or Fold Right operation, which starts at the corresponding side and moves through the payload. The returned instance of data.Data is used as the aggregate in the subsequent call.

type Fork added in v0.5.0 

type Fork func(list []*Packet) (a, b []*Packet)

Fork is a function for splitting the payload into 2 separate paths. Default Forks for duplication and error checking are provided by ForkDuplicate and ForkError respectively. 

var (
	// ForkDuplicate is a Fork that creates a deep copy of the
	// payload and sends it down both branches.
	ForkDuplicate Fork = func(payload []*Packet) (a, b []*Packet) {
		payload2 := []*Packet{}
		buf := &bytes.Buffer{}
		enc, dec := gob.NewEncoder(buf), gob.NewDecoder(buf)

		_ = enc.Encode(payload)
		_ = dec.Decode(&payload2)

		return payload, payload2
	}

	// ForkError is a Fork that splits machine.Packets based on
	// the presence of an error. Errors are sent down the
	// right side path.
	ForkError Fork = func(payload []*Packet) (s, f []*Packet) {
		s = []*Packet{}
		f = []*Packet{}

		for _, packet := range payload {
			if len(packet.Errors) > 0 {
				f = append(f, packet)
			} else {
				s = append(s, packet)
			}
		}

		return s, f
	}
)

type ForkRule added in v0.5.0 

type ForkRule func(d data.Data) bool

ForkRule is a function that can be converted to a Fork via the Handler method allowing for Forking based on the contents of the data.

func (ForkRule) Handler added in v0.5.0 

func (r ForkRule) Handler(payload []*Packet) (t, f []*Packet)

Handler is a method for turning the ForkRule into an instance of Fork

type HTTPStream added in v0.16.0 

type HTTPStream interface {
	Stream
	Handler() fiber.Handler
	InjectionHandlers() map[string]fiber.Handler
}

HTTPStream is a Stream that also provides a fiber.Handler for receiving data

func LoadHTTP added in v0.16.4 

func LoadHTTP(serialization *StreamSerialization) (HTTPStream, error)

LoadHTTP method loads an HTTPStream based on the StreamSerialization

func NewHTTPStream added in v0.16.0 

func NewHTTPStream(id string, opts ...*Option) HTTPStream

NewHTTPStream a method that creates a Stream which takes in data through a fiber.Handler

func NewWebsocketStream added in v0.16.0 

func NewWebsocketStream(id string, opts ...*Option) HTTPStream

NewWebsocketStream a method that creates a Stream which takes in data through a fiber.Handler that runs a websocket

type Option added in v0.2.0 

type Option struct {
	// DeepCopy uses encoding/gob to create a deep copy of the payload
	// before the processing to ensure concurrent map exceptions cannot
	// happen. Is fairly resource intensive so use with caution.
	// Default: false
	DeepCopy *bool
	// FIFO controls the processing order of the payloads
	// If set to true the system will wait for one payload
	// to be processed before starting the next.
	// Default: false
	FIFO *bool
	// Injectable controls whether the vertex accepts injection calls
	// if set to false the data will be logged and processing will not
	// take place.
	// Default: true
	Injectable *bool
	// BufferSize sets the buffer size on the edge channels between the
	// vertices, this setting can be useful when processing large amounts
	// of data with FIFO turned on.
	// Default: 0
	BufferSize *int
	// Span controls whether opentelemetry spans are created for tracing
	// Packets processed by the system.
	// Default: true
	Span *bool
	// Metrics controls whether opentelemetry metrics are recorded for
	// Packets processed by the system.
	// Default: true
	Metrics *bool

	Provider EdgeProvider
}

Option type for holding machine settings.

type Packet 

type Packet struct {
	ID     string           `json:"id"`
	Data   data.Data        `json:"data"`
	Errors map[string]error `json:"errors"`
}

Packet type that holds information traveling through the machine.

type PluginDefinition added in v0.11.0 

type PluginDefinition struct {
	// Type is the name of the PluginProvider to use.
	Type string `json:"type" mapstructure:"type"`
	// Payload is the location, script, etc provided to load the plugin.
	// Depends on the PluginProvider.
	Payload string `json:"payload" mapstructure:"payload"`
	// Symbol is the name of the symbol to be loaded from the plugin.
	Symbol string `json:"symbol" mapstructure:"symbol"`
	// Attributes are a map[string]interface{} of properties to be used with the PluginProvider.
	Attributes map[string]interface{} `json:"attributes" mapstructure:"attributes"`
}

PluginDefinition type for declaring the path and symbol for a golang plugin containing the Provider

type PluginProvider added in v0.11.0 

type PluginProvider interface {
	Load(*PluginDefinition) (interface{}, error)
}

PluginProvider interface for providing a way of loading plugins must return one of the following types: 

Subscription
Retriever
Applicative
Fold
Fork
Publisher

type Publisher added in v0.12.0 

type Publisher interface {
	Send([]data.Data) error
}

Publisher is an interface for sending data out of the Stream

type Remover added in v0.16.5 

type Remover func(index int, d data.Data) bool

Remover func that is used to remove Data based on a true result

type Retriever added in v0.3.0 

type Retriever func(ctx context.Context) chan []data.Data

Retriever is a function that provides data to a generic Stream must stop when the context receives a done signal.

type Stream added in v0.5.0 

type Stream interface {
	ID() string
	Run(ctx context.Context) error
	Inject(id string, payload ...*Packet)
	VertexIDs() []string
	Builder() Builder
	Errors() chan error
}

Stream is a representation of a data stream and its associated logic. Creating a new Stream is handled by the appropriately named NewStream function.

The Builder method is the entrypoint into creating the data processing flow. All branches of the Stream are required to end in either a Publish or a Link in order to be considered valid.

func Load added in v0.16.0 

func Load(serialization *StreamSerialization) (Stream, error)

Load method loads a stream based on the StreamSerialization

func NewStream added in v0.5.0 

func NewStream(id string, retriever Retriever, options ...*Option) Stream

NewStream is a function for creating a new Stream. It takes an id, a Retriever function, and a list of Options that can override the defaults and set new defaults for the subsequent vertices in the Stream.

func NewSubscriptionStream added in v0.16.0 

func NewSubscriptionStream(id string, sub Subscription, interval time.Duration, opts ...*Option) Stream

NewSubscriptionStream creates a Stream from the provider Subscription and pulls data continuously after an interval amount of time

type StreamSerialization added in v0.11.0 

type StreamSerialization struct {
	// Type type of stream to create.
	//
	// For root serializations valid values are 'http', 'subscription', or 'stream'.
	Type string `json:"type,omitempty" mapstructure:"type,omitempty"`
	// Interval is the duration in nanoseconds between pulls in a 'subscription' Type. It is only read
	// if the Type is 'subscription'.
	Interval time.Duration `json:"interval,omitempty" mapstructure:"interval,omitempty"`
	// Options are a slice of machine.Option https://godoc.org/github.com/whitaker-io/machine#Option
	Options []*Option `json:"options,omitempty" mapstructure:"options,omitempty"`

	*VertexSerialization
}

StreamSerialization config based definition for a stream

func (*StreamSerialization) MarshalJSON added in v0.12.4 

func (s *StreamSerialization) MarshalJSON() ([]byte, error)

MarshalJSON implementation to marshal json

func (*StreamSerialization) MarshalYAML added in v0.11.0 

func (s *StreamSerialization) MarshalYAML() (interface{}, error)

MarshalYAML implementation to marshal yaml

func (*StreamSerialization) UnmarshalJSON added in v0.12.4 

func (s *StreamSerialization) UnmarshalJSON(data []byte) error

UnmarshalJSON implementation to unmarshal json

func (*StreamSerialization) UnmarshalYAML added in v0.11.0 

func (s *StreamSerialization) UnmarshalYAML(unmarshal func(interface{}) error) error

UnmarshalYAML implementation to unmarshal yaml

type Subscription added in v0.7.0 

type Subscription interface {
	Read(ctx context.Context) []data.Data
	Close() error
}

Subscription is an interface for creating a pull based stream. It requires 2 methods Read and Close.

Read is called when the interval passes and the resulting payload is sent down the Stream.

Close is called during a graceful termination and any errors are logged.

type VertexSerialization added in v0.11.0 

type VertexSerialization struct {
	// ID unique identifier for the stream.
	ID string `json:"id,omitempty" mapstructure:"id,omitempty"`
	// Provider Plugin information to load
	Provider *PluginDefinition `json:"provider,omitempty" mapstructure:"provider,omitempty"`
	// contains filtered or unexported fields
}

VertexSerialization config based definition for a stream vertex

Source Files

View all Source files

Directories

Path Synopsis
cmd module
common module
edge
http Module
pubsub Module
telemetry module

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