Atiesh

Atiesh is an open-source stream-processing framework, developed on top of akka-actor (classic) with builtin simple and reliable backpressure mechanism.

In WoW, Atiesh is the Greatstaff of the Guardian, hope that you use it open a portal for your data-stream just like what Medivh do for the Orc :>

Components and Events

There are three types of basic components for construct your stream data flow

• Source
• Interceptor
• Sink

And messages which passed through them are wrapped into event, the default event class is atiesh.event.SimpleEvent

The Extension type of component is use as helper & support component (e.g.:atiesh.utils.http.CachedProxy), which based on atiesh.utils.AtieshExtension

Life cycle and basic unit of data stream

The basic unit of data (or messages) is represented as event, they were consumed or accepted by source from some external system and wrapped into event class, intercepted (modify or filter) by one or more specified Interceptor, and finally send to one sink which drain these event (e.g.: wrap it/them into http request, batch process, etc.) and send it to some external system, right after that, the messages processing for a batch or a single message is completed

Built-in Components List

Component Name	Type	Usage
atiesh.source.DevZero	Source	generate and produce string "0"
atiesh.source.DirectoryWatchSource	Source	poll event from local directory
atiesh.source.KafkaSource	Source	poll event from kafka brokers
atiesh.source.HttpSource	Source	extra events from incoming http requests
atiesh.interceptor.DevNull	Interceptor	intercept and discard everything
atiesh.interceptor.Transparent	Interceptor	intercept and forward everything
atiesh.sink.DevNull	Sink	drain and discard everything
atiesh.sink.KafkaSink	Sink	drain and write event to kafka
atiesh.sink.HttpSink	Sink	drain and write event to http remote
atiesh.utils.http.CachedProxy	Extension	external http access & cache tool

• These sink and source components provide very simple functionality just for demonstrate component development
• The DevNull sink drain and discard everything, which means you can use it to avoid noise like no sink found inside your log
• The CachedProxy extension can be use as simple remote configuration syncer

Components and Semantics

Component is the basic abstract to implement you own data processor (act as sink or source or interceptor). On the other hand, Semantics is the abstract layer to implement your own protocols (e.g.: talk to http, communicate with kafka), they were intended to be used as mixins of your Component implemenation (the Scala cake pattern) via extends ... with ... with ... inside you class definition

The built-in components and semantics was splited to several different projects, and thanks to that, we now have a very tiny core project with a few dependencies

GroupID	ArtifactID	Description
com.typesafe	config	configuration read & parse
io.kamon	kamon-core	monitor data collection
	kamon-system-metrics	monitor data support
com.typesafe.akka	akka-actor	core actor library
com.typesafe.scala-logging	scala-logging	logging support

Built-in Semantics

The BatchSinkSemantics was inside the core project, others are not

Semantics Class FQDN	Semantics Type	Descriptions
atiesh.sink.BatchSinkSemantics	SinkSemantics	Batch Mode Support
atiesh.sink.HttpSinkSemantics	SinkSemantics	Protocol Support - Http Client
atiesh.sink.HttpLimitRequestSinkSemantics	SinkSemantics	Protocol Support - Http Client (HighLevel API)
atiesh.source.HttpSourceSemantics	SourceSemantics	Protocol Support - Http Server
atiesh.sink.KafkaSinkSemantics	SinkSemantics	Protocol Support - Kafka Producer
atiesh.sink.KafkaLimitAckSinkSemantics	SinkSemantics	Protocol Support - Kafka Producer (HighLevel API)
atiesh.sink.KafkaSynchronousAckSinkSemantics	SinkSemantics	Protocol Support - Kafka Producer (HighLevel API)
atiesh.source.KafkaSourceSemantics	SourceSemantics	Protocol Support - Kafka Consumer
atiesh.source.DirectoryWatchSourceSemantics	SourceSemantics	Protocol Support - FS Directory Watch
atiesh.sink.SyslogSinkSemantics	SinkSemantics	Protocol Support - Syslog
atiesh.sink.AliyunSLSSinkSemantics	SinkSemantics	Protocol Support - Aliyun SLS Producer

API Levels

Only the source and sink components can extends by semantics, and their api was splited to three levels

• Component API, component abstract api, should implement the event process method and component startup and shutdown method
• Semantics API, semantics abstract api, provide a way to interact with the ActorSystem of akka-actor and the backpressure/start/stop transactions (internally, they are Scala Promise)
• Internal API, internal abstract api, just for declare the basic abstract method and implement the internal Actor of akka-actor of that component, and you should not touch any of these

Component Configure Example

Assume that you need a data-stream which read records from kafka topic incoming-channel, and log each record, finally discard them all

akka { ... }
kamon { ... }

atiesh {
    # block for declare source component(s)
    source {
        # declare a source component which:
        #   name - <kafka-consumer>
        #   data processor (reader) class - <atiesh.source.KafkaSource>
        #   data interceptor component - <records-logger>
        #   data processor (writer) component - <devnull>
        #   standard kafka consumer properties - <group.id = cg-atiesh, ...>
        kafka-consumer {
            fqcn = "atiesh.source.KafkaSource"

            interceptors = ["records-logger"]
            sinks = ["devnull"]

            topics = ["incoming-channel"]
            poll-timeout = 1000 ms

            kafka-properties {
                "group.id" = "cg-atiesh"
                "bootstrap.servers" = "kafka-broker-01.0ops.io:9092,kafka-broker-02.0ops.io:9092,..."
                "enable.auto.commit" = true
                "auto.commit.interval.ms" = 30000
                "session.timeout.ms" = 30000
                "key.deserializer" = "org.apache.kafka.common.serialization.StringDeserializer"
                "value.deserializer" = "org.apache.kafka.common.serialization.StringDeserializer"
                ...
            }
        }
    }

    # block for declare interceptor component(s)
    interceptor {
        # declare a interceptor component which:
        #   name - <records-logger>
        #   data processor (interceptor) class - <atiesh.interceptor.Transparent>
        #   data interceptor priority - <90>
        records-logger {
            fqcn = "atiesh.interceptor.Transparent"
            priority = 90
        }
    }

    # block for declare sink component(s)
    sink {
        # declare a sink component which:
        #   name - <devnull>
        #   data processor (sink) class - <atiesh.sink.DevNull>
        devnull {
            fqcn = "atiesh.sink.DevNull"
        }
    }

    # block for declare extension component(s)
    extension {
        ...
    }
}

• The atiesh server will construct all necessary classes and assemble a data-stream pipeline by concatenate these classes
• Component construct order: extension => interceptor => sink => source
• Component shutdown order: source => sink => extension

License

Atiesh is Open Soure and available under the MIT License

Author and Maintainer

Hao Feng < whisperaven@gmail.com >