Adding example of Client Reset

dependencies.list

@@ -7,10 +7,10 @@ REALM_CORE=10.3.3
 MONGODB_REALM_SERVER=2021-03-09
 
 # Common Android settings across projects
-GRADLE_BUILD_TOOLS=4.0.0
+GRADLE_BUILD_TOOLS=4.1.0
 ANDROID_BUILD_TOOLS=29.0.3
-KOTLIN=1.3.72
-KOTLIN_COROUTINES=1.3.9
+KOTLIN=1.4.31
+KOTLIN_COROUTINES=1.4.2
 
 # Common classpath dependencies
 gradle=6.5

examples/mongoDbRealmExample/build.gradle

@@ -34,13 +34,10 @@ android {
 
     buildTypes {
         // Configure server and App Id.
-        // The default server is https://realm-dev.mongodb.com/ . Go to that and copy the MongoDB
+        // The default server is https://realm.mongodb.com/ . Go to that and copy the MongoDB
         // Realm App Id.
-        //
-        // If you are running a local version of MongoDB Realm, modify endpoint accordingly. Most
-        // likely it is "http://localhost:9090"
-        def mongodbRealmUrl = "https://realm-dev.mongodb.com"
-        def appId = "my-app-id"
+        def mongodbRealmUrl = "https://realm.mongodb.com"
+        def appId = "counter-app-snuns"
         debug {
             buildConfigField "String", "MONGODB_REALM_URL", "\"${mongodbRealmUrl}\""
             buildConfigField "String", "MONGODB_REALM_APP_ID", "\"${appId}\""
@@ -65,8 +62,9 @@ realm {
 }
 
 dependencies {
-    implementation 'androidx.appcompat:appcompat:1.1.0'
-    implementation 'com.google.android.material:material:1.1.0'
+    implementation 'androidx.appcompat:appcompat:1.2.0'
+    implementation 'androidx.lifecycle:lifecycle-viewmodel:2.3.0'
+    implementation 'com.google.android.material:material:1.3.0'
     implementation 'me.zhanghai.android.materialprogressbar:library:1.6.1'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 }

examples/mongoDbRealmExample/src/main/AndroidManifest.xml

@@ -18,7 +18,13 @@
         </activity>
         <activity
             android:name=".LoginActivity"
-            android:label="Login"></activity>
+            android:label="Login">
+        </activity>
+        <activity
+            android:name=".ClientResetActivity"
+            android:launchMode="singleInstance"
+            android:label="ClientReset">
+        </activity>
     </application>
 
 </manifest>

examples/mongoDbRealmExample/src/main/java/com/mongodb/realm/example/ClientResetActivity.kt

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2021 Realm Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.mongodb.realm.example
+
+import android.os.Bundle
+import android.os.SystemClock
+import android.view.View
+import android.widget.TextView
+import android.widget.Toast
+import androidx.appcompat.app.AppCompatActivity
+import androidx.databinding.DataBindingUtil
+import com.mongodb.realm.example.databinding.ActivityClientresetBinding
+import io.realm.*
+import io.realm.mongodb.sync.*
+import me.zhanghai.android.materialprogressbar.MaterialProgressBar
+import java.util.*
+import java.util.concurrent.ConcurrentLinkedQueue
+
+/**
+ * This class is used as an example on how to implement Client Reset.
+ *
+ * This activity is launched with `singleInstance` so no matter how many times it is
+ * started only one instance is running. However, when finished, it will just return to whatever is
+ * on the top of navigation stack.
+ *
+ * Pressing back has been disabled to prevent the [clientResetHelper] from accidentally running
+ * while another Activity is displayed.
+ */
+class ClientResetActivity : AppCompatActivity() {
+
+    companion object {
+        // Track Client Reset errors as a queue of errors as the chance of all Realms
+        // connected to a single app instance experiencing Client Resets is quite high, e.g.
+        // in the case where Sync was terminated then restarted on the server.
+        var RESET_ERRORS = ConcurrentLinkedQueue<Pair<ClientResetRequiredError, SyncConfiguration>>()
+    }
+
+    // Run Client Reset logic on a separate helper thread to make it easier to implement timeouts.
+    // Note, this Runnable is not particular safe as it will continue running even if the Activity
+    // is excited
+    private val clientResetHelper = Runnable {
+        var errorReported = false;
+        ClientResetLoop@ while(true) {
+            val error: Pair<ClientResetRequiredError, SyncConfiguration> = RESET_ERRORS.poll() ?: break
+            val clientReset: ClientResetRequiredError = error.first
+            val config: SyncConfiguration = error.second
+
+            // The background Sync Client take about 10 seconds to fully close the connection and thus
+            // the background Realm. Set timeout to 20 seconds.
+            var maxWait = 20
+            while (Realm.getGlobalInstanceCount(config) > 0) {
+                if (maxWait == 0) {
+                    runOnUiThread {
+                        progressBar.visibility = View.INVISIBLE
+                        statusView.text = "'${config.realmFileName}' did not fully close, so database could not be reset. Aborting"
+                    }
+                    errorReported = true
+                    break@ClientResetLoop
+                } else {
+                    maxWait--
+                    runOnUiThread {
+                        statusView.text = "Waiting for '${config.realmFileName}' to fully close ($maxWait): ${Realm.getGlobalInstanceCount(config)}"
+                    }
+                    SystemClock.sleep(1000)
+                }
+            }
+            clientReset.executeClientReset()
+            runOnUiThread {
+                statusView.text = ""
+            }
+        }
+        if (!errorReported) {
+            finish()
+        }
+    }
+
+    private lateinit var binding: ActivityClientresetBinding
+
+    private lateinit var statusView: TextView
+    private lateinit var progressBar: MaterialProgressBar
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        binding = DataBindingUtil.setContentView(this, R.layout.activity_clientreset)
+        statusView = binding.status
+        progressBar = binding.progressbar
+    }
+
+    override fun onResume() {
+        super.onResume()
+        Thread(clientResetHelper).start();
+    }
+
+    override fun onBackPressed() {
+        Toast.makeText(
+                this,
+                "Pressing 'Back' is disabled while Client Reset is running.",
+                Toast.LENGTH_LONG
+        ).show()
+    }
+}

examples/mongoDbRealmExample/src/main/java/com/mongodb/realm/example/CounterActivity.kt

@@ -32,10 +32,7 @@ import io.realm.kotlin.syncSession
 import io.realm.kotlin.where
 import io.realm.log.RealmLog
 import io.realm.mongodb.User
-import io.realm.mongodb.sync.ProgressListener
-import io.realm.mongodb.sync.ProgressMode
-import io.realm.mongodb.sync.SyncConfiguration
-import io.realm.mongodb.sync.SyncSession
+import io.realm.mongodb.sync.*
 import me.zhanghai.android.materialprogressbar.MaterialProgressBar
 import java.util.*
 import java.util.concurrent.atomic.AtomicBoolean
@@ -97,43 +94,37 @@ class CounterActivity : AppCompatActivity() {
         user = loggedInUser
         val user = user
         if (user != null) {
-            // Create a RealmConfiguration for our user
-            // Use user id as partition value, so each user gets an unique view.
-            // FIXME Right now we are using waitForInitialRemoteData and a more advanced
-            // initialData block due to Sync only supporting ObjectId keys. This should
-            // be changed once natural keys are supported.
+            // Create a RealmConfiguration for our user. Use user id as partition value, so each
+            // user gets an unique view.
             val config = SyncConfiguration.Builder(user, user.id)
                     .initialData {
-                        if (it.isEmpty) {
-                            it.insert(CRDTCounter())
-                        }
+                        it.insert(CRDTCounter(user.id))
+                    }
+                    .clientResetHandler { session, error ->
+                        ClientResetActivity.RESET_ERRORS.add(Pair(error, session.configuration))
+                        val intent = Intent(this, ClientResetActivity::class.java)
+                        startActivity(intent)
                     }
-                    .waitForInitialRemoteData()
                     .build()
 
-            // This will automatically sync all changes in the background for as long as the Realm is open
-            Realm.getInstanceAsync(config, object: Realm.Callback() {
-                override fun onSuccess(realm: Realm) {
-                    [email protected] = realm
-
-                    counter = realm.where<CRDTCounter>().findFirstAsync()
-                    counter.addChangeListener<CRDTCounter> { obj, _ ->
-                        if (obj.isValid) {
-                            counterView.text = String.format(Locale.US, "%d", counter.count)
-                        } else {
-                            counterView.text = "-"
-                        }
+            realm = Realm.getInstance(config).also {
+                counter = it.where<CRDTCounter>().findFirstAsync()
+                counter.addChangeListener<CRDTCounter> { obj, _ ->
+                    if (obj.isValid) {
+                        counterView.text = String.format(Locale.US, "%d", counter.count)
+                    } else {
+                        counterView.text = "-"
                     }
+                }
 
-                    // Setup progress listeners for indeterminate progress bars
-                    session = realm.syncSession
-                    session.run {
-                        addDownloadProgressListener(ProgressMode.INDEFINITELY, downloadListener)
-                        addUploadProgressListener(ProgressMode.INDEFINITELY, uploadListener)
-                    }
+                // Setup progress listeners for indeterminate progress bars
+                session = it.syncSession
+                session.run {
+                    addDownloadProgressListener(ProgressMode.INDEFINITELY, downloadListener)
+                    addUploadProgressListener(ProgressMode.INDEFINITELY, uploadListener)
                 }
-            })
-            counterView.text = "-"
+                counterView.text = "-"
+            }
         }
     }
 
@@ -144,6 +135,7 @@ class CounterActivity : AppCompatActivity() {
                 removeProgressListener(downloadListener)
                 removeProgressListener(uploadListener)
             }
+            // Close Realm here to make sure it is closed when navigating to other Activities.
             realm?.close()
         }
     }
@@ -156,15 +148,16 @@ class CounterActivity : AppCompatActivity() {
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
         return when (item.itemId) {
             R.id.action_logout -> {
-                val user = user
-                user?.logOutAsync {
-                    if (it.isSuccess) {
-                        realm?.close()
-                        this.user = loggedInUser
-                    } else {
-                        RealmLog.error(it.error.toString())
-                    }
-                }
+//                val user = user
+//                user?.logOutAsync {
+//                    if (it.isSuccess) {
+//                        realm?.close()
+//                        this.user = loggedInUser
+//                    } else {
+//                        RealmLog.error(it.error.toString())
+//                    }
+//                }
+                ResetHelper.triggerClientReset(user!!.app.sync, realm!!.syncSession)
                 true
             }
             else -> super.onOptionsItemSelected(item)

examples/mongoDbRealmExample/src/main/java/com/mongodb/realm/example/model/CRDTCounter.kt

@@ -22,11 +22,15 @@ import io.realm.annotations.RealmField
 import io.realm.annotations.Required
 import org.bson.types.ObjectId
 
-open class CRDTCounter : RealmObject() {
+open class CRDTCounter(userId: String) : RealmObject() {
+
+    // Required by Realm
+    constructor(): this("")
 
     @PrimaryKey
     @RealmField("_id")
-    var id: ObjectId = ObjectId.get()
+    var id: String = userId
+
     @Required
     private val counter: MutableRealmInteger = MutableRealmInteger.valueOf(0L)
 

examples/mongoDbRealmExample/src/main/java/io/realm/mongodb/sync/ResetHelper.kt

@@ -0,0 +1,9 @@
+package io.realm.mongodb.sync
+
+class ResetHelper {
+    companion object {
+        fun triggerClientReset(sync: Sync, session: SyncSession) {
+            sync.simulateClientReset(session)
+        }
+    }
+}

examples/mongoDbRealmExample/src/main/res/layout/activity_clientreset.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <data />
+
+    <RelativeLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <LinearLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:gravity="center_horizontal"
+            android:padding="32dp"
+            android:layout_centerInParent="true"
+            android:orientation="vertical">
+
+            <me.zhanghai.android.materialprogressbar.MaterialProgressBar
+                android:id="@+id/progressbar"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginBottom="64dp"
+                android:layout_gravity="center_horizontal"
+                android:indeterminate="true"
+                style="@style/Widget.MaterialProgressBar.ProgressBar" />
+
+            <TextView
+                android:id="@+id/status"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:textSize="12sp"
+                app:fontFamily="sans-serif" />
+        </LinearLayout>
+
+    </RelativeLayout>
+</layout>
+