DOCSP-41760 Add transactions page (#167)

* Add transactions page, add language variable, include code snippet for transactions

---------

Co-authored-by: Rea Rustagi <[email protected]>
Co-authored-by: Brandon Ly <[email protected]>
Co-authored-by: rustagir <[email protected]>
(cherry picked from commit e0c22ee)

examples/src/test/kotlin/SearchIndexesTest.kt

@@ -53,7 +53,6 @@ class SearchIndexesTest {
     }
 
     @Ignore
-    @Test
     fun multipleSearchIndexTest() = runBlocking {
         // :snippet-start: multi-search-index-create
         val indexOne = SearchIndexModel(

examples/src/test/kotlin/TransactionsTest.kt

@@ -0,0 +1,86 @@
+import com.mongodb.kotlin.client.coroutine.MongoClient
+import com.mongodb.client.model.Filters.eq
+import com.mongodb.client.model.Updates.inc
+import config.getConfig
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.Assertions.assertNotNull
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TransactionsTest {
+
+    // :snippet-start: data-class
+    data class Account(
+        val accountId: String,
+        val amount: Int
+    )
+    // :snippet-end:
+
+    companion object {
+        val config = getConfig()
+        val client = MongoClient.create(config.connectionUri)
+        val database = client.getDatabase("bank")
+
+        @BeforeAll
+        @JvmStatic
+        fun beforeAll() {
+            runBlocking {
+                val savAcct = Account("9876", 900)
+                database.getCollection<Account>("savings_accounts").insertOne(savAcct)
+
+                val chkAcct = Account("9876", 50)
+                database.getCollection<Account>("checking_accounts").insertOne(chkAcct)
+            }
+        }
+
+        @AfterAll
+        @JvmStatic
+        fun afterAll() {
+            runBlocking {
+                database.drop()
+                client.close()
+            }
+        }
+    }
+
+    @Test
+    fun transactionTest() = runBlocking {
+        // :snippet-start: transaction-function
+        // Set up the session
+        val session = client.startSession()
+
+        try {
+            session.startTransaction()
+
+            val savingsColl = database
+                .getCollection<Account>("savings_accounts")
+            val checkingColl = database
+                .getCollection<Account>("checking_accounts")
+
+            savingsColl.findOneAndUpdate(
+                session,
+                eq(Account::accountId.name, "9876"),
+                inc(Account::amount.name, -100),
+            )
+
+            checkingColl.findOneAndUpdate(
+                session,
+                eq(Account::accountId.name, "9876"),
+                inc(Account::amount.name, 100)
+            )
+
+            // Commit the transaction
+            val result = session.commitTransaction()
+            println("Transaction committed.")
+            assertNotNull(result) // :remove:
+        } catch (error: Exception) {
+            println("An error occurred during the transaction: ${error.message}")
+            // Abort the transaction
+            session.abortTransaction()
+        }
+        // :snippet-end:
+    }
+}

snooty.toml

@@ -21,6 +21,7 @@ driver-short = "Kotlin driver"
 driver-long = "MongoDB Kotlin Driver"
 version = "5.0"
 full-version = "{+version+}.0"
+language = "Kotlin"
 mdb-server = "MongoDB server"
 kotlin-docs = "https://kotlinlang.org"
 

source/examples/generated/TransactionsTest.snippet.data-class.kt

@@ -0,0 +1,4 @@
+data class Account(
+    val accountId: String,
+    val amount: Int
+)

source/examples/generated/TransactionsTest.snippet.transaction-function.kt

@@ -0,0 +1,31 @@
+// Set up the session
+val session = client.startSession()
+
+try {
+    session.startTransaction()
+
+    val savingsColl = database
+        .getCollection<Account>("savings_accounts")
+    val checkingColl = database
+        .getCollection<Account>("checking_accounts")
+
+    savingsColl.findOneAndUpdate(
+        session,
+        eq(Account::accountId.name, "9876"),
+        inc(Account::amount.name, -100),
+    )
+
+    checkingColl.findOneAndUpdate(
+        session,
+        eq(Account::accountId.name, "9876"),
+        inc(Account::amount.name, 100)
+    )
+
+    // Commit the transaction
+    val result = session.commitTransaction()
+    println("Transaction committed.")
+} catch (error: Exception) {
+    println("An error occurred during the transaction: ${error.message}")
+    // Abort the transaction
+    session.abortTransaction()
+}

source/fundamentals.txt

@@ -19,6 +19,7 @@ Fundamentals
    /fundamentals/aggregation
    /fundamentals/aggregation-expression-operations
    /fundamentals/indexes
+   /fundamentals/transactions
    /fundamentals/collations
    /fundamentals/logging
    /fundamentals/monitoring

source/fundamentals/transactions.txt

@@ -0,0 +1,130 @@
+.. _kotlin-fundamentals-transactions:
+
+============
+Transactions
+============
+
+.. facet::
+   :name: genre
+   :values: reference
+
+.. meta::
+   :keywords: modify, customize
+
+.. contents:: On this page
+   :local:
+   :backlinks: none
+   :depth: 2
+   :class: singlecol
+
+Overview
+--------
+
+In this guide, you can learn how to use the {+driver-short+} to perform 
+**transactions**. :manual:`Transactions </core/transactions/>` allow
+you to run a series of operations that do not change any data until the
+transaction is committed. If any operation in the transaction returns an
+error, the driver cancels the transaction and discards all data changes
+before they ever become visible.
+
+In MongoDB, transactions run within logical **sessions**. A
+:manual:`session </reference/server-sessions/>` is a grouping of related
+read or write operations that you intend to run sequentially. Sessions
+enable :manual:`causal consistency
+</core/read-isolation-consistency-recency/#causal-consistency>` for a
+group of operations or allow you to execute operations in an
+:website:`ACID transaction </basics/acid-transactions>`. MongoDB
+guarantees that the data involved in your transaction operations remains
+consistent, even if the operations encounter unexpected errors.
+
+When using the {+driver-short+}, you can create a new session from a 
+``MongoClient`` instance as a ``ClientSession``. We recommend that you reuse
+your client for multiple sessions and transactions instead of
+instantiating a new client each time.
+
+.. warning::
+
+   Use a ``ClientSession`` only with the ``MongoClient`` (or associated
+   ``MongoDatabase`` or ``MongoCollection``) that created it. Using a
+   ``ClientSession`` with a different ``MongoClient`` results in operation
+   errors.
+
+Methods
+-------
+
+Create a ``ClientSession`` by using the ``startSession()`` method on your
+``Client`` instance. You can then modify the session state by using the
+following methods:
+
+.. list-table::
+   :widths: 25 75
+   :header-rows: 1
+
+   * - Method
+     - Description
+
+   * - ``startTransaction()``
+     - | Starts a new transaction for this session with the
+         default transaction options. You cannot start a
+         transaction if there's already an active transaction
+         on the session.
+       |
+       | To set transaction options, use ``startTransaction(transactionOptions: TransactionOptions)``.
+
+   * - ``abortTransaction()``
+     - | Ends the active transaction for this session. Returns an error 
+         if there is no active transaction for the
+         session or the transaction was previously ended.
+
+   * - ``commitTransaction()``
+     - | Commits the active transaction for this session. Returns an
+         error if there is no active transaction for the session or if the
+         transaction was ended.
+
+A ``ClientSession`` also has methods to retrieve session properties and modify
+mutable session properties. View the `API documentation <{+api+}/apidocs/mongodb-driver-kotlin-coroutine/mongodb-driver-kotlin-coroutine/com.mongodb.kotlin.client.coroutine/-client-session/index.html>`__
+to learn more about these methods.
+
+Example
+-------
+
+This example uses the following {+language+} data class to model its documents:
+
+.. literalinclude:: /examples/generated/TransactionsTest.snippet.data-class.kt
+   :language: kotlin
+
+The following example demonstrates how you can create a session, create a transaction,
+and commit changes to existing documents:
+
+1. Create a session from the client using the ``startSession()`` method.
+#. Use the ``startTransaction()`` method to start a transaction.
+#. Update the specified documents, then use the ``commitTransaction()`` method if all
+   operations succeed, or ``abortTransaction()`` if any operations fail.
+
+.. literalinclude:: /examples/generated/TransactionsTest.snippet.transaction-function.kt
+   :language: kotlin
+
+Additional Information
+----------------------
+
+To learn more about the concepts mentioned in this guide, see the following pages in 
+the Server manual:
+
+- :manual:`Transactions </core/transactions/>`
+- :manual:`Server Sessions </reference/server-sessions>`
+- :manual:`Read Isolation, Consistency, and Recency </core/read-isolation-consistency-recency/#causal-consistency>`
+
+To learn more about ACID compliance, see the :website:`What are ACID
+Properties in Database Management Systems? </basics/acid-transactions>`
+article on the MongoDB website.
+
+API Documentation
+~~~~~~~~~~~~~~~~~
+
+To learn more about any of the types or methods discussed in this
+guide, see the following API Documentation:
+
+- `ClientSession <{+api+}/apidocs/mongodb-driver-kotlin-coroutine/mongodb-driver-kotlin-coroutine/com.mongodb.kotlin.client.coroutine/-client-session/index.html>`__
+- `startTransaction <{+api+}/apidocs/mongodb-driver-kotlin-coroutine/mongodb-driver-kotlin-coroutine/com.mongodb.kotlin.client.coroutine/-client-session/start-transaction.html>`__
+- `commitTransaction <{+api+}/apidocs/mongodb-driver-kotlin-coroutine/mongodb-driver-kotlin-coroutine/com.mongodb.kotlin.client.coroutine/-client-session/commit-transaction.html>`__
+- `abortTransaction <{+api+}/apidocs/mongodb-driver-kotlin-coroutine/mongodb-driver-kotlin-coroutine/com.mongodb.kotlin.client.coroutine/-client-session/abort-transaction.html>`__