Alpha With State Machine

Quick Start

The state machine mode save completed transaction data to elasticsearch

run postgress

docker run -d -e "POSTGRES_DB=saga" -e "POSTGRES_USER=saga" -e "POSTGRES_PASSWORD=password" -p 5432:5432 postgres

run elasticsearch

docker run --name elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" elasticsearch:6.6.2

run Alpha use alpha.feature.akka.enabled=true enabled state machine mode support

java -jar alpha-server-${version}-exec.jar \
  --spring.datasource.url=jdbc:postgresql://0.0.0.0:5432/saga?useSSL=false \
  --spring.datasource.username=saga \
  --spring.datasource.password=password \
  --spring.profiles.active=prd \
  --alpha.feature.akka.enabled=true \
  --alpha.feature.akka.transaction.repository.type=elasticsearch \
  --spring.data.elasticsearch.cluster-name=docker-cluster \
  --spring.data.elasticsearch.cluster-nodes=localhost:9300

NOTE： spring.data.elasticsearch.cluster-name is elasticsearch cluster name, default is docker-cluster when run elasticsearch with docker, you can query cluster name by curl http://localhost:9200/

Omega
use alpha.feature.akka.enabled=true enabled state machine mode support
```
alpha.feature.akka.enabled=true
```
WEB
Open http://localhost:8090/admin in browser, Screencast
Dashboard
Transactions List
Transaction Details - Successful
Transaction Details - Compensated
Transaction Details - Failed

APIs

Metrics

You can query Alpha metrics by RESTful API, Use the AlphaBenchmark to simulate sending data and quickly experience this feature.

For exapmle; 10 concurrencies and send 1000 global transactions

java -jar alpha-benchmark-0.5.0-SNAPSHOT-exec.jar --alpha.cluster.address=0.0.0.0:8080 --w=0 --n=1000 --c=10

Query metrics

curl http://localhost:8090/alpha/api/v1/metrics

{
  nodeType: "MASTER",
  metrics: {
    eventReceived: 8000,
    eventAccepted: 8000,
    eventRejected: 0,
    eventAvgTime: 0,
    actorReceived: 8000,
    actorAccepted: 8000,
    actorRejected: 0,
    actorAvgTime: 0,
    sagaBeginCounter: 1000,
    sagaEndCounter: 1000,
    sagaAvgTime: 9,
    committed: 1000,
    compensated: 0,
    suspended: 0,
    repositoryReceived: 1000,
    repositoryAccepted: 1000,
    repositoryRejected: 0,
    repositoryAvgTime: 0.88
  }
}

description

eventReceived: number of gRPC events received
eventAccepted: number of gRPC events accepted（events into the channel）
eventRejected: number of gRPC events rejected
eventAvgTime: average elapsed time on events (milliseconds)
actorReceived: number of events received by actor
actorAccepted: number of events accepted by actor
actorRejected: number of events rejected by actor
actorAvgTime: average elapsed time on actor (milliseconds)
sagaBeginCounter: saga global transaction start counter
sagaEndCounter: saga global transaction end counter
sagaAvgTime: average elapsed time on saga global transaction (milliseconds)
committed: number of committed
compensated: number of compensated
suspended: number of suspended
repositoryReceived: number of events received by the repository component
repositoryAccepted: number of events accepted by the repository component
repositoryRejected: number of events rejected by the repository component
repositoryAvgTime: average elapsed time on save data (milliseconds)

Query Transaction

Query all transactions

curl -X GET http://localhost:8090/alpha/api/v1/transaction?page=0&size=50

{
  "total": 2002,
  "page": 0,
  "size": 50,
  "elapsed": 581,
  "globalTransactions": [...]
}

Request

page
size

Response

total
page
size
elapsed
globalTransactions

Query transaction by globalTxId
```
curl -X GET http://localhost:8090/alpha/api/v1/transaction/{globalTxId}

{
  "globalTxId": "e00a3bac-de6b-498f-99a4-c11d3087fd14",
  "type": "SAGA",
  "serviceName": "alpha-benchmark",
  "instanceId": "alpha-benchmark-127.0.0.1",
  "beginTime": 1564762932963,
  "endTime": 1564762933197,
  "state": "COMMITTED",
  "subTxSize": 3,
  "durationTime": 408,
  "subTransactions": [...],
  "events": [...]
}
```
Request
- globalTxId: global transaction id
Response
- globalTxId: global transaction id
- type: SAGA or TCC
- serviceName: global transaction initiator service name
- instanceId: global transaction initiator instance id
- beginTime: global transaction start time
- endTime: global transaction end time
- state: global transaction final state (COMMITTED or COMPENSATED or SUSPENDED)
- subTxSize: number of sub-transaction
- durationTime
- subTransactions: sub-transaction list
- events: event list

Transactional Data Persistence

Only the end of the transaction will be persisted to Elasticsearch, the transaction data in execution is persisted by Akka.

The end transaction has the following

End of successfully: final state is COMMITTED
End of compensation: final state is COMPENSATED
End of abnormal: final state is SUSPENDED
The following situations can lead to an abnormal end
1. timeout
2. Alpha received an unexpected event, For example, Alpha receive TxEndedEvent before TxStartedEvent or did not receive any sub-transaction events before receiving SagaEndedEvent

Persistent Configuration

name	default	description
alpha.feature.akka.transaction.repository.type		Default is not persistent，currently only supports the elasticsearch option
alpha.feature.akka.transaction.repository.elasticsearch.memory.size	-1	Persistence wait queue length, default is Integer.MAX
alpha.feature.akka.transaction.repository.elasticsearch.batchSize	100	Batch size
alpha.feature.akka.transaction.repository.elasticsearch.refreshTime	5000	Refresh time
spring.data.elasticsearch.cluster-name		ES集群名称
spring.data.elasticsearch.cluster-nodes		El;asticsearch address, For example, ip:9300

Elasticsearch Index Name

Alpha will automatically create an index alpha_global_transaction

Query By Elasticsearch APIs

Query all transactions

curl http://localhost:9200/alpha_global_transaction/_search

Query transaction by globalTxId

curl -X POST http://localhost:9200/alpha_global_transaction/_search -H 'Content-Type: application/json' -d '
{
  "query": {
    "bool": {
      "must": [{
        "term": {
          "globalTxId.keyword": "974d089a-5476-48ed-847a-1e338456809b"
        }
      }],
      "must_not": [],
      "should": []
    }
  },
  "from": 0,
  "size": 10,
  "sort": [],
  "aggs": {}
}'

Result json data

{
  "took": 17,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4874,
    "max_score": 1.0,
    "hits": [{
      "_index": "alpha_global_transaction",
      "_type": "alpha_global_transaction_type",
      "_id": "209791a0-34f4-40da-807e-9c5b8786dd61",
      "_score": 1.0,
      "_source": {
        "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
        "type": "SAGA",
        "serviceName": "alpha-benchmark",
        "instanceId": "alpha-benchmark-127.0.0.1",
        "beginTime": 1563982631298,
        "endTime": 1563982631320,
        "state": "COMMITTED",
        "subTxSize": 3,
        "durationTime": 22,
        "subTransactions": [...],
        "events": [...]
      }
    },{...}]
  }
}

Result data sample

{
  "took": 17,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4874,
    "max_score": 1.0,
    "hits": [{
      "_index": "alpha_global_transaction",
      "_type": "alpha_global_transaction_type",
      "_id": "209791a0-34f4-40da-807e-9c5b8786dd61",
      "_score": 1.0,
      "_source": {
        "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
        "type": "SAGA",
        "serviceName": "alpha-benchmark",
        "instanceId": "alpha-benchmark-127.0.0.1",
        "beginTime": 1563982631298,
        "endTime": 1563982631320,
        "state": "COMMITTED",
        "subTxSize": 3,
        "durationTime": 22,
        "subTransactions": [{
          "localTxId": "03fe15b2-a070-4e55-9b5b-801c2181dd0a",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "beginTime": 1563982631308,
          "endTime": 1563982631309,
          "state": "COMMITTED",
          "durationTime": 1
        }, {
          "localTxId": "923f83fd-0bce-4fac-8c89-ecbe7c5e9106",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "beginTime": 1563982631320,
          "endTime": 1563982631320,
          "state": "COMMITTED",
          "durationTime": 0
        }, {
          "localTxId": "95821ce3-2202-4e55-9343-4e6a6519821f",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "beginTime": 1563982631309,
          "endTime": 1563982631309,
          "state": "COMMITTED",
          "durationTime": 0
        }],
        "events": [{
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "createTime": 1563982631298,
          "timeout": 0,
          "type": "SagaStartedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "03fe15b2-a070-4e55-9b5b-801c2181dd0a",
          "createTime": 1563982631299,
          "compensationMethod": "service a",
          "payloads": "AQE=",
          "retryMethod": "",
          "retries": 0,
          "type": "TxStartedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "03fe15b2-a070-4e55-9b5b-801c2181dd0a",
          "createTime": 1563982631301,
          "type": "TxEndedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "95821ce3-2202-4e55-9343-4e6a6519821f",
          "createTime": 1563982631302,
          "compensationMethod": "service b",
          "payloads": "AQE=",
          "retryMethod": "",
          "retries": 0,
          "type": "TxStartedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "95821ce3-2202-4e55-9343-4e6a6519821f",
          "createTime": 1563982631304,
          "type": "TxEndedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "923f83fd-0bce-4fac-8c89-ecbe7c5e9106",
          "createTime": 1563982631309,
          "compensationMethod": "service c",
          "payloads": "AQE=",
          "retryMethod": "",
          "retries": 0,
          "type": "TxStartedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "923f83fd-0bce-4fac-8c89-ecbe7c5e9106",
          "createTime": 1563982631311,
          "type": "TxEndedEvent"
        }, {
          "serviceName": "alpha-benchmark",
          "instanceId": "alpha-benchmark-127.0.0.1",
          "globalTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "parentTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "localTxId": "209791a0-34f4-40da-807e-9c5b8786dd61",
          "createTime": 1563982631312,
          "type": "SagaEndedEvent"
        }]
      }
    }]
  }
}

more references Elasticsearch APIs

High Availability

You can achieve high availability of services by deploying an Alpha cluster. You can choose the type of event channel by parameter itself.

Event Channel Type

Alpha receives the event sent by Omega and puts it into the event channel to wait for Akka processing.

Type	模式	description
memory（default）	single	Using memory as data channel, Not recommended for use in production environments
redis（coming soon）	master-slave	Using redis PUB/SUB as data channel. Only the primary node is responsible for processing the data, After the master node is down, the slave node switches to the master node.
kafka（coming soon）	cluster	Using Kafka as the data channel and global transaction ID as the partitioning strategy, support horizontally scalable.

Memory channel

name	default	description
alpha.feature.akka.channel.type	memory
alpha.feature.akka.channel.memory.size	-1	queue size, default is Integer.MAX

Redis channel
coming soon
Kafka channel
coming soon

Akka Configuration

Use the prefix akkaConfig before the parameter name of akka

Akka Persistence

Default

akkaConfig.akka.persistence.journal.plugin=akka.persistence.journal.inmem
akkaConfig.akka.persistence.journal.leveldb.dir=target/example/journal
akkaConfig.akka.persistence.snapshot-store.plugin=akka.persistence.snapshot-store.local
akkaConfig.akka.persistence.snapshot-store.local.dir=target/example/snapshots

Redis

akkaConfig.akka.persistence.journal.plugin=akka-persistence-redis.journal
akkaConfig.akka.persistence.snapshot-store.plugin=akka-persistence-redis.snapshot
akkaConfig.akka-persistence-redis.redis.mode=simple
akkaConfig.akka-persistence-redis.redis.host=localhost
akkaConfig.akka-persistence-redis.redis.port=6379
akkaConfig.akka-persistence-redis.redis.database=0

more references akka-persistence-redis

Usage example

java -jar alpha-server-${version}-exec.jar \
  --spring.datasource.url=jdbc:postgresql://0.0.0.0:5432/saga?useSSL=false \
  --spring.datasource.username=saga-user \
  --spring.datasource.password=saga-password \
  --spring.profiles.active=prd \
  --alpha.feature.akka.enabled=true \
  --alpha.feature.akka.transaction.repository.type=elasticsearch \
  --spring.data.elasticsearch.cluster-name=docker-cluster \
  --spring.data.elasticsearch.cluster-nodes=localhost:9300 \
  --akkaConfig.akka.persistence.journal.plugin=akka-persistence-redis.journal \
  --akkaConfig.akka.persistence.snapshot-store.plugin=akka-persistence-redis.snapshot \
  --akkaConfig.akka-persistence-redis.redis.mode=simple \
  --akkaConfig.akka-persistence-redis.redis.host=localhost \
  --akkaConfig.akka-persistence-redis.redis.port=6379 \
  --akkaConfig.akka-persistence-redis.redis.database=0

Akka Cluster

coming soon

Appendix

design document

benchmark