Add exception handler

Author: xinlili-statsig

src/main/kotlin/com/statsig/sdk/StatsigServer.kt

@@ -195,6 +195,7 @@ private class StatsigServerImpl() :
     override var initialized = false
 
     override fun setup(serverSecret: String, options: StatsigOptions) {
+        Thread.setDefaultUncaughtExceptionHandler(MainThreadExceptionHandler(this, Thread.currentThread()))
         errorBoundary = ErrorBoundary(serverSecret, options, statsigMetadata)
         coroutineExceptionHandler = CoroutineExceptionHandler { _, ex ->
             // no-op - supervisor job should not throw when a child fails
@@ -209,6 +210,10 @@ private class StatsigServerImpl() :
 
     override suspend fun initialize(serverSecret: String, options: StatsigOptions) {
         setup(serverSecret, options)
+        initializeImpl(serverSecret, options)
+    }
+
+    private suspend fun initializeImpl(serverSecret: String, options: StatsigOptions) {
         errorBoundary.capture(
             "initialize",
             {
@@ -512,7 +517,7 @@ private class StatsigServerImpl() :
     override fun initializeAsync(serverSecret: String, options: StatsigOptions): CompletableFuture<Void?> {
         setup(serverSecret, options)
         return statsigScope.future {
-            initialize(serverSecret, options)
+            initializeImpl(serverSecret, options)
             null
         }
     }
@@ -787,4 +792,15 @@ private class StatsigServerImpl() :
         diagnostics?.logDiagnostics(ContextType.INITIALIZE)
         diagnostics.diagnosticsContext = ContextType.CONFIG_SYNC
     }
+
+    class MainThreadExceptionHandler(val server: StatsigServer, val currentThread: Thread) : Thread.UncaughtExceptionHandler {
+        override fun uncaughtException(t: Thread, e: Throwable) {
+            if (!t.name.equals(currentThread.name)) {
+                throw e
+            }
+            println("[Statsig]: Shutting down Statsig because of unhandled exception from your server")
+            server.shutdown()
+            throw e
+        }
+    }
 }

src/test/java/com/statsig/sdk/ExceptionHandlerTest.kt

@@ -0,0 +1,101 @@
+package com.statsig.sdk
+
+import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import com.google.gson.ToNumberPolicy
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.runBlocking
+import okhttp3.mockwebserver.Dispatcher
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import okhttp3.mockwebserver.RecordedRequest
+import org.junit.Before
+import org.junit.Test
+
+class ExceptionHandlerTest {
+    private lateinit var gson: Gson
+    private lateinit var eventLogInputCompletable: CompletableDeferred<LogEventInput>
+    private lateinit var evaluator: Evaluator
+    private lateinit var driver: StatsigServer
+    private lateinit var user: StatsigUser
+    private lateinit var options: StatsigOptions
+
+    @Before
+    fun setUp() {
+        gson = GsonBuilder().setObjectToNumberStrategy(ToNumberPolicy.LONG_OR_DOUBLE).create()
+        user = StatsigUser("abc")
+        eventLogInputCompletable = CompletableDeferred()
+
+        val mockGateResponse = APIFeatureGate("a_gate", true, "ruleID")
+        val mockResponseBody = gson.toJson(mockGateResponse)
+
+        val downloadConfigSpecsResponse =
+            StatsigE2ETest::class.java.getResource("/layer_exposure_download_config_specs.json")?.readText() ?: ""
+
+        val server = MockWebServer()
+        server.apply {
+            dispatcher = object : Dispatcher() {
+                @Throws(InterruptedException::class)
+                override fun dispatch(request: RecordedRequest): MockResponse {
+                    when (request.path) {
+                        "/v1/download_config_specs" -> {
+                            return MockResponse().setResponseCode(200).setBody(downloadConfigSpecsResponse)
+                        }
+                        "/v1/check_gate" -> {
+                            return MockResponse().setResponseCode(200).setBody(mockResponseBody)
+                        }
+                        "/v1/log_event" -> {
+                            val logBody = request.body.readUtf8()
+                            eventLogInputCompletable.complete(gson.fromJson(logBody, LogEventInput::class.java))
+                            return MockResponse().setResponseCode(200)
+                        }
+                    }
+                    return MockResponse().setResponseCode(404)
+                }
+            }
+        }
+
+        options = StatsigOptions().apply {
+            api = server.url("/v1").toString()
+            disableDiagnostics = true
+        }
+
+        driver = StatsigServer.create()
+    }
+
+    @Test
+    fun testDaemonThreadException() = runBlocking {
+        driver.initialize("server-key", options)
+        val daemon = Thread({
+            throw Exception("Throwing from daemon thread")
+        })
+        daemon.isDaemon = true
+        daemon.start()
+        assert(driver.initialized)
+    }
+
+    @Test
+    fun testThrowingNonDaemon() = runBlocking {
+        driver.initialize("server-key", options)
+        val nonDaemon = Thread({
+            throw Exception("Throwing from non-daemon thread")
+        })
+        nonDaemon.start()
+        // For exception throw in other thread, we don't handle
+        assert(driver.initialized)
+        driver.shutdown()
+        assert(!driver.initialized)
+    }
+
+    @Test
+    fun testThrowingOnSameThread() = runBlocking {
+        val t = Thread {
+            runBlocking {
+                driver.initialize("server-key", options)
+            }
+            throw java.lang.Exception("throw exception")
+        }
+        t.start()
+        assert(!driver.initialized)
+    }
+}

src/test/java/com/statsig/sdk/StatsigOptionsTest.kt

@@ -19,7 +19,7 @@ class StatsigOptionsTest {
             "PRODUCTION" to "production",
             "STAGING" to "staging",
             "Development" to "development",
-            "Custom Tier" to "custom tier"
+            "Custom Tier" to "custom tier",
         )
 
         for ((inputTier, expectedTier) in tierTestCases) {
@@ -33,7 +33,7 @@ class StatsigOptionsTest {
         val parameterTestCases = mapOf(
             "key1" to "value1",
             "key2" to "value2",
-            "key1" to "updatedValue1"
+            "key1" to "updatedValue1",
         )
 
         for ((key, value) in parameterTestCases) {