MongoDB

cosid-mongo stores segment counters and machine id leases in MongoDB, through the application's synchronous MongoClient:

• MongoIdSegmentDistributor: segment counters, one document per generator in the cosid collection.
• MongoMachineLeaseStore: machine id leases, one document per machine id in the cosid_machine collection. Lease times come from the server's localTime (hello command).

The collections are created at startup when missing.

Synchronous driver only

The reactive classes (me.ahoo.cosid.mongo.reactive) were removed in 4.0. Use the synchronous driver, org.mongodb:mongodb-driver-sync, which spring-boot-starter-data-mongodb includes. With only the reactive driver on the classpath, the starter fails at startup.

Installation

Gradle (Kotlin)

dependencies {
    implementation(platform("me.ahoo.cosid:cosid-bom:$cosidVersion"))
    implementation("me.ahoo.cosid:cosid-spring-boot-starter")
    implementation("me.ahoo.cosid:cosid-mongo")
    implementation("org.springframework.boot:spring-boot-starter-data-mongodb")
}

Maven

<dependencies>
    <dependency>
        <groupId>me.ahoo.cosid</groupId>
        <artifactId>cosid-spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>me.ahoo.cosid</groupId>
        <artifactId>cosid-mongo</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-mongodb</artifactId>
    </dependency>
</dependencies>

Configuration

spring:
  mongodb:
    uri: mongodb://localhost:27017
cosid:
  namespace: ${spring.application.name}
  machine:
    enabled: true # for Snowflake IDs and CosIdGenerator
    distributor:
      type: mongo
  segment:
    enabled: true # for segment IDs
    distributor:
      type: mongo

Property	Default	Description
cosid.segment.distributor.mongo.database	cosid_db	Database of the cosid collection
cosid.segment.distributor.mongo.timeout	5s	Each segment operation (driver timeoutMS); 0 disables it
cosid.machine.distributor.mongo.database	cosid_db	Database of the cosid_machine collection
cosid.machine.distributor.mongo.timeout	5s	Each machine id operation (driver timeoutMS); must be positive

Run MongoDB with journaling (the default) and write concern majority on a replica set, so that an acknowledged counter update survives a failover.