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create EventStreamInPostgresql

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This commit is contained in:
Fabrice Lecomte
2025-03-29 02:42:26 +01:00
parent a427bf88c7
commit d9e05e6d9a
10 changed files with 214 additions and 63 deletions
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7
migrations/events/V1__init_event_table.sql Normal file
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@@ -0,0 +1,7 @@
create table event_stream (
id uuid not null primary key,
aggregate_id uuid not null,
version int not null,
data jsonb not null,
unique(aggregate_id, version)
);

2
src/main/kotlin/eventDemo/libs/event/EventStore.kt
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@@ -3,7 +3,7 @@ package eventDemo.libs.event
import io.github.oshai.kotlinlogging.withLoggingContext
interface EventStore<E : Event<ID>, ID : AggregateId> {
fun getStream(aggregateId: ID): EventStream<E>
fun getStream(aggregateId: ID): EventStream<E, ID>
fun publish(event: E) =
withLoggingContext("event" to event.toString()) {

4
src/main/kotlin/eventDemo/libs/event/EventStoreInMemory.kt
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@@ -4,8 +4,8 @@ import java.util.concurrent.ConcurrentHashMap
import java.util.concurrent.ConcurrentMap
class EventStoreInMemory<E : Event<ID>, ID : AggregateId> : EventStore<E, ID> {
private val streams: ConcurrentMap<ID, EventStream<E>> = ConcurrentHashMap()
private val streams: ConcurrentMap<ID, EventStream<E, ID>> = ConcurrentHashMap()
override fun getStream(aggregateId: ID): EventStream<E> =
override fun getStream(aggregateId: ID): EventStream<E, ID> =
streams.computeIfAbsent(aggregateId) { EventStreamInMemory(aggregateId) }
}

12
src/main/kotlin/eventDemo/libs/event/EventStoreInPostgresql.kt Normal file
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@@ -0,0 +1,12 @@
package eventDemo.libs.event
import javax.sql.DataSource
class EventStoreInPostgresql<E : Event<ID>, ID : AggregateId>(
private val dataSource: DataSource,
private val objectToString: (E) -> String,
private val stringToObject: (String) -> E,
) : EventStore<E, ID> {
override fun getStream(aggregateId: ID): EventStream<E, ID> =
EventStreamInPostgresql(aggregateId, dataSource, objectToString, stringToObject)
}

4
src/main/kotlin/eventDemo/libs/event/EventStream.kt
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@@ -6,7 +6,9 @@ import io.github.oshai.kotlinlogging.withLoggingContext
/**
* Interface representing an event stream for publishing and reading domain events
*/
interface EventStream<E : Event<*>> {
interface EventStream<E : Event<ID>, ID : AggregateId> {
val aggregateId: ID
/** Publishes a single event to the event stream */
fun publish(event: E)

4
src/main/kotlin/eventDemo/libs/event/EventStreamInMemory.kt
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@@ -10,8 +10,8 @@ import java.util.concurrent.ConcurrentLinkedQueue
* All methods are implemented.
*/
class EventStreamInMemory<E : Event<ID>, ID : AggregateId>(
val aggregateId: ID,
) : EventStream<E> {
override val aggregateId: ID,
) : EventStream<E, ID> {
private val logger = KotlinLogging.logger {}
private val events: Queue<E> = ConcurrentLinkedQueue()

105
src/main/kotlin/eventDemo/libs/event/EventStreamInPostgresql.kt Normal file
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@@ -0,0 +1,105 @@
package eventDemo.libs.event
import io.github.oshai.kotlinlogging.KotlinLogging
import org.postgresql.util.PGobject
import javax.sql.DataSource
/**
* An In-Memory implementation of an event stream.
*
* All methods are implemented.
*/
class EventStreamInPostgresql<E : Event<ID>, ID : AggregateId>(
override val aggregateId: ID,
private val dataSource: DataSource,
private val objectToString: (E) -> String,
private val stringToObject: (String) -> E,
) : EventStream<E, ID> {
private val logger = KotlinLogging.logger {}
override fun publish(event: E) {
if (event.aggregateId != aggregateId) {
throw EventStreamPublishException(
"You cannot publish this event in this stream because it has a different aggregateId!",
)
}
dataSource.connection.use { connection ->
connection
.prepareStatement(
"""
insert into event_stream(id, aggregate_id, version, data)
values (?, ?, ?, ?)
""".trimIndent(),
).use {
it.setObject(1, event.eventId)
it.setObject(2, event.aggregateId.id)
it.setInt(3, event.version)
it.setObject(4, PGJsonb(objectToString(event)))
it.executeUpdate()
}
}
logger.info { "Event published" }
}
override fun readAll(): Set<E> =
dataSource.connection.use { connection ->
connection
.prepareStatement(
"""
select data
from event_stream
where aggregate_id = ?
order by version asc
""".trimIndent(),
).use {
it.setObject(1, aggregateId.id)
it.executeQuery().use { resultSet ->
buildSet {
while (resultSet.next()) {
resultSet
.getString("data")
.let(stringToObject)
.let { add(it) }
}
}
}
}
}
override fun readVersionBetween(version: IntRange): Set<E> =
dataSource.connection.use { connection ->
connection
.prepareStatement(
"""
select data
from event_stream
where version between ? and ?
and aggregate_id = ?
order by version asc
""".trimIndent(),
).use { stmt ->
stmt.setInt(1, version.first)
stmt.setInt(2, version.last)
stmt.setObject(3, aggregateId.id)
stmt.executeQuery().use { resultSet ->
buildSet {
while (resultSet.next()) {
resultSet
.getString("data")
.let(stringToObject)
.let { add(it) }
}
}
}
}
}
}
class PGJsonb(
value: String,
) : PGobject() {
init {
this.value = value
this.type = "jsonb"
}
}

7
src/test/kotlin/eventDemo/Helpers.kt
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@@ -19,11 +19,8 @@ fun Deck.allCards(): Set<Card> =
stack + discard + playersHands.values.flatten()
@KoinApplicationDslMarker
suspend fun testKoinApplicationWithConfig(block: suspend Koin.() -> Unit) {
koinApplication { modules(appKoinModule(ApplicationConfig("application.conf").configuration())) }.koin.apply {
block()
}
}
suspend fun <T> testKoinApplicationWithConfig(block: suspend Koin.() -> T): T =
koinApplication { modules(appKoinModule(ApplicationConfig("application.conf").configuration())) }.koin.block()
@KtorDsl
suspend fun testApplicationWithConfig(block: suspend ApplicationTestBuilder.(koin: Koin) -> Unit) {

131
src/test/kotlin/eventDemo/libs/event/EventStreamInMemoryTest.kt
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@@ -1,11 +1,15 @@
package eventDemo.libs.event
import eventDemo.testKoinApplicationWithConfig
import io.kotest.core.spec.style.FunSpec
import io.kotest.datatest.withData
import io.kotest.matchers.collections.shouldHaveSize
import io.kotest.matchers.equals.shouldBeEqual
import kotlinx.coroutines.DelicateCoroutinesApi
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.joinAll
import kotlinx.coroutines.launch
import kotlinx.serialization.json.Json
import org.junit.jupiter.api.assertNull
import org.junit.jupiter.api.assertThrows
import kotlin.test.assertNotNull
@@ -13,73 +17,96 @@ import kotlin.test.assertNotNull
@DelicateCoroutinesApi
class EventStreamInMemoryTest :
FunSpec({
fun streamWith3Events(block: EventStream<Event<IdTest>>.(id: IdTest) -> Unit): EventStream<Event<IdTest>> =
EventStreamInMemory(IdTest()).apply {
fun EventStream<EventXTest, IdTest>.with3Events(block: EventStream<EventXTest, IdTest>.(id: IdTest) -> Unit) =
also {
publish(EventXTest(aggregateId = aggregateId, version = 1, num = 1))
publish(EventXTest(aggregateId = aggregateId, version = 2, num = 2))
publish(EventXTest(aggregateId = aggregateId, version = 3, num = 3))
block(aggregateId)
}
test("readVersionBetween should only return the event of aggregate") {
streamWith3Events {
readVersionBetween(1..2) shouldHaveSize 2
readVersionBetween(1..1) shouldHaveSize 1
readVersionBetween(2..20) shouldHaveSize 2
readVersionBetween(4..20) shouldHaveSize 0
suspend fun eventStreams(): List<EventStream<EventXTest, IdTest>> =
testKoinApplicationWithConfig {
listOf(
EventStreamInMemory(IdTest()),
EventStreamInPostgresql(
IdTest(),
dataSource = get(),
objectToString = { Json.encodeToString(it) },
stringToObject = { Json.decodeFromString(it) },
),
)
}
context("readVersionBetween should only return the event of aggregate") {
withData(eventStreams()) { stream ->
stream.with3Events {
readVersionBetween(1..2) shouldHaveSize 2
readVersionBetween(1..1) shouldHaveSize 1
readVersionBetween(2..20) shouldHaveSize 2
readVersionBetween(4..20) shouldHaveSize 0
}
}
}
test("readAll should only return the event of aggregate") {
streamWith3Events {
readAll() shouldHaveSize 3
readAll().also {
it.forEachIndexed { i, event ->
event.version shouldBeEqual i + 1
context("readAll should only return the event of aggregate") {
withData(eventStreams()) { stream ->
stream.with3Events {
readAll() shouldHaveSize 3
readAll().also {
it.forEachIndexed { i, event ->
event.version shouldBeEqual i + 1
}
}
}
}
}
test("getByVersion should only return the event with this version") {
streamWith3Events {
assertNotNull(getByVersion(1)).version shouldBeEqual 1
assertNotNull(getByVersion(2)).version shouldBeEqual 2
assertNotNull(getByVersion(3)).version shouldBeEqual 3
assertNull(getByVersion(4))
}
}
test("readGreaterOfVersion should only return the events with greater version") {
streamWith3Events {
assertNotNull(readGreaterOfVersion(1)) shouldHaveSize 2
assertNotNull(readGreaterOfVersion(2)) shouldHaveSize 1
assertNotNull(readGreaterOfVersion(3)) shouldHaveSize 0
assertNotNull(readGreaterOfVersion(30)) shouldHaveSize 0
}
}
test("publish should be throw error when publish another aggregate event") {
EventStreamInMemory(IdTest()).apply {
assertThrows<EventStreamPublishException> { publish(EventXTest(aggregateId = IdTest(), version = 1, num = 1)) }
}
}
test("publish should be concurrently secure") {
val id = IdTest()
val stream = EventStreamInMemory(id)
(1..10).forEach { i1 ->
GlobalScope.launch {
(1..10).forEach { i2 ->
stream.publish(
EventXTest(
aggregateId = id,
version = (i1 * 10) + i2,
num = (i1 * 10) + i2,
),
)
}
context("getByVersion should only return the event with this version") {
withData(eventStreams()) { stream ->
stream.with3Events {
assertNotNull(getByVersion(1)).version shouldBeEqual 1
assertNotNull(getByVersion(2)).version shouldBeEqual 2
assertNotNull(getByVersion(3)).version shouldBeEqual 3
assertNull(getByVersion(4))
}
}
}
context("readGreaterOfVersion should only return the events with greater version") {
withData(eventStreams()) {
it.with3Events {
assertNotNull(readGreaterOfVersion(1)) shouldHaveSize 2
assertNotNull(readGreaterOfVersion(2)) shouldHaveSize 1
assertNotNull(readGreaterOfVersion(3)) shouldHaveSize 0
assertNotNull(readGreaterOfVersion(30)) shouldHaveSize 0
}
}
}
context("publish should be throw error when publish another aggregate event") {
withData(eventStreams()) {
assertThrows<EventStreamPublishException> { it.publish(EventXTest(aggregateId = IdTest(), version = 1, num = 1)) }
}
}
context("publish should be concurrently secure") {
withData(eventStreams()) { stream ->
(0..9)
.map { i1 ->
GlobalScope.launch {
(1..10).forEach { i2 ->
stream.publish(
EventXTest(
aggregateId = stream.aggregateId,
version = (i1 * 10) + i2,
num = (i1 * 10) + i2,
),
)
}
}
}.joinAll()
stream.readAll() shouldHaveSize 100
}
}
})

1
src/test/kotlin/eventDemo/libs/event/TestEvents.kt
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@@ -13,6 +13,7 @@ value class IdTest(
override val id: UUID = UUID.randomUUID(),
) : AggregateId
@Serializable
sealed interface TestEvents : Event<IdTest>
@Serializable