android: move common yaml configuration down to java layer

library/java/src/io/envoyproxy/envoymobile/engine/BUILD

@@ -22,7 +22,6 @@ envoy_mobile_java_library(
     name = "envoy_base_engine_lib",
     srcs = [
         "EnvoyConfiguration.java",
-        "EnvoyConfigurationImpl.java",
         "EnvoyEngine.java",
         "EnvoyEngineImpl.java",
         "EnvoyHTTPStream.java",

library/java/src/io/envoyproxy/envoymobile/engine/EnvoyConfiguration.java

@@ -1,11 +1,46 @@
 package io.envoyproxy.envoymobile.engine;
 
-public interface EnvoyConfiguration {
+public class EnvoyConfiguration {
+
+  public final Integer connectTimeoutSeconds;
+  public final Integer dnsRefreshSeconds;
+  public final Integer statsFlushSeconds;
 
   /**
-   * Provides a default configuration template that may be used for starting Envoy.
+   * Create an EnvoyConfiguration with a user provided configuration values.
    *
-   * @return A template that may be used as a starting point for constructing configurations.
+   * @param connectTimeoutSeconds timeout for new network connections to hosts in the cluster.
+   * @param dnsRefreshSeconds rate in seconds to refresh DNS.
+   * @param statsFlushSeconds interval at which to flush Envoy stats.
    */
-  String templateString();
+  public EnvoyConfiguration(int connectTimeoutSeconds, int dnsRefreshSeconds,
+                            int statsFlushSeconds) {
+    this.connectTimeoutSeconds = connectTimeoutSeconds;
+    this.dnsRefreshSeconds = dnsRefreshSeconds;
+    this.statsFlushSeconds = statsFlushSeconds;
+  }
+
+  /**
+   * Resolves the provided configuration template using properties on this configuration.
+   * This default configuration is provided by the native layer.
+   *
+   * @param templateYAML the default template configuration.
+   * @return String, the resolved template.
+   * @throws ConfigurationException, when the template provided is not fully resolved.
+   */
+  String resolveTemplate(String templateYAML) {
+    String resolvedConfiguration =
+        templateYAML.replace("{{ connect_timeout }}", String.format("%ss", connectTimeoutSeconds))
+            .replace("{{ dns_refresh_rate }}", String.format("%ss", dnsRefreshSeconds))
+            .replace("{{ stats_flush_interval }}", String.format("%ss", statsFlushSeconds));
+
+    if (resolvedConfiguration.contains("{{")) {
+      throw new ConfigurationException();
+    }
+    return resolvedConfiguration;
+  }
+
+  static class ConfigurationException extends RuntimeException {
+    ConfigurationException() { super("Unresolved Template Key"); }
+  }
 }

library/java/src/io/envoyproxy/envoymobile/engine/EnvoyEngine.java

@@ -12,19 +12,19 @@ public interface EnvoyEngine {
   EnvoyHTTPStream startStream(EnvoyObserver observer);
 
   /**
-   * Run the Envoy engine with the provided config and log level.
+   * Run the Envoy engine with the provided yaml string and log level.
    *
-   * @param config The configuration file with which to start Envoy.
+   * @param configurationYAML The configuration yaml with which to start Envoy.
    * @return A status indicating if the action was successful.
    */
-  int runWithConfig(String config);
+  int runWithConfig(String configurationYAML, String logLevel);
 
   /**
-   * Run the Envoy engine with the provided config and log level.
+   * Run the Envoy engine with the provided EnvoyConfiguration and log level.
    *
-   * @param config   The configuration file with which to start Envoy.
+   * @param envoyConfiguration The EnvoyConfiguration used to start Envoy.
    * @param logLevel The log level to use when starting Envoy.
    * @return int A status indicating if the action was successful.
    */
-  int runWithConfig(String config, String logLevel);
+  int runWithConfig(EnvoyConfiguration envoyConfiguration, String logLevel);
 }

library/java/src/io/envoyproxy/envoymobile/engine/EnvoyEngineImpl.java

@@ -24,30 +24,30 @@ public EnvoyHTTPStream startStream(EnvoyObserver observer) {
   }
 
   /**
-   * Run the Envoy engine with the provided config and log level.
+   * Run the Envoy engine with the provided yaml string and log level.
    *
-   * @param config The configuration file with which to start Envoy.
+   * @param configurationYAML The configuration yaml with which to start Envoy.
    * @return A status indicating if the action was successful.
    */
   @Override
-  public int runWithConfig(String config) {
-    return runWithConfig(config, "info");
+  public int runWithConfig(String configurationYAML, String logLevel) {
+    try {
+      return JniLibrary.runEngine(configurationYAML, logLevel);
+    } catch (Throwable throwable) {
+      // TODO: Need to have a way to log the exception somewhere
+      return 1;
+    }
   }
 
   /**
-   * Run the Envoy engine with the provided config and log level.
+   * Run the Envoy engine with the provided envoyConfiguration and log level.
    *
-   * @param config   The configuration file with which to start Envoy.
+   * @param envoyConfiguration The EnvoyConfiguration used to start Envoy.
    * @param logLevel The log level to use when starting Envoy.
    * @return int A status indicating if the action was successful.
    */
   @Override
-  public int runWithConfig(String config, String logLevel) {
-    try {
-      return JniLibrary.runEngine(config, logLevel);
-    } catch (Throwable throwable) {
-      // TODO: Need to have a way to log the exception somewhere
-      return 1;
-    }
+  public int runWithConfig(EnvoyConfiguration envoyConfiguration, String logLevel) {
+    return runWithConfig(envoyConfiguration.resolveTemplate(JniLibrary.templateString()), logLevel);
   }
 }

library/java/test/io/envoyproxy/envoymobile/engine/BUILD

@@ -0,0 +1,13 @@
+licenses(["notice"])  # Apache 2
+
+load("//bazel:kotlin_test.bzl", "envoy_mobile_kt_test")
+
+envoy_mobile_kt_test(
+    name = "envoy_configuration_test",
+    srcs = [
+        "EnvoyConfigurationTest.kt",
+    ],
+    deps = [
+        "//library/kotlin/src/io/envoyproxy/envoymobile:envoy_interfaces_lib",
+    ],
+)

library/java/test/io/envoyproxy/envoymobile/engine/EnvoyConfigurationTest.kt

@@ -0,0 +1,33 @@
+package io.envoyproxy.envoymobile.engine
+
+import org.junit.Test
+
+private const val TEST_CONFIG = """
+mock_template:
+- name: mock
+  connect_timeout: {{ connect_timeout }}
+  dns_refresh_rate: {{ dns_refresh_rate }}
+  stats_flush_interval: {{ stats_flush_interval }}
+"""
+
+
+class EnvoyConfigurationTest {
+
+  @Test
+  fun `resolving with default configuration resolves with values`() {
+    val envoyConfiguration = EnvoyConfiguration(123, 234, 345)
+
+    val resolvedTemplate = envoyConfiguration.resolveTemplate(TEST_CONFIG)
+    assertThat(resolvedTemplate).contains("connect_timeout: 123s")
+    assertThat(resolvedTemplate).contains("dns_refresh_rate: 234s")
+    assertThat(resolvedTemplate).contains("stats_flush_interval: 345s")
+  }
+
+
+  @Test(expected = ConfigurationException::class)
+  fun `resolve templates with invalid templates will throw on build`() {
+    val envoyConfiguration = EnvoyConfiguration(123, 234, 345)
+
+    envoyConfiguration.resolveTemplate("{{ }}")
+  }
+}

library/kotlin/src/io/envoyproxy/envoymobile/Envoy.kt

@@ -1,5 +1,6 @@
 package io.envoyproxy.envoymobile
 
+import io.envoyproxy.envoymobile.engine.EnvoyConfiguration
 import io.envoyproxy.envoymobile.engine.EnvoyEngine
 import java.nio.ByteBuffer
 
@@ -19,17 +20,23 @@ enum class LogLevel(internal val level: String) {
 /**
  * Wrapper class that allows for easy calling of Envoy's JNI interface in native Java.
  */
-class Envoy constructor(
+class Envoy private constructor(
     private val engine: EnvoyEngine,
-    internal val config: String,
-    internal val logLevel: LogLevel = LogLevel.INFO
+    internal val envoyConfiguration: EnvoyConfiguration?,
+    internal val configurationYAML: String?,
+    internal val logLevel: LogLevel
 ) : Client {
 
-  constructor(engine: EnvoyEngine, config: String) : this(engine, config, LogLevel.INFO)
+  constructor(engine: EnvoyEngine, envoyConfiguration: EnvoyConfiguration, logLevel: LogLevel = LogLevel.INFO) : this(engine, envoyConfiguration, null, logLevel)
+  constructor(engine: EnvoyEngine, configurationYAML: String, logLevel: LogLevel = LogLevel.INFO) : this(engine, null, configurationYAML, logLevel)
 
   // Dedicated thread for running this instance of Envoy.
   private val runner: Thread = Thread(ThreadGroup("Envoy"), Runnable {
-    engine.runWithConfig(config.trim(), logLevel.level)
+    if (envoyConfiguration == null) {
+      engine.runWithConfig(configurationYAML, logLevel.level)
+    }else {
+      engine.runWithConfig(envoyConfiguration, logLevel.level)
+    }
   })
 
   /**

library/kotlin/src/io/envoyproxy/envoymobile/EnvoyBuilder.kt

@@ -1,29 +1,20 @@
 package io.envoyproxy.envoymobile
 
 import io.envoyproxy.envoymobile.engine.EnvoyConfiguration
-import io.envoyproxy.envoymobile.engine.EnvoyConfigurationImpl
 import io.envoyproxy.envoymobile.engine.EnvoyEngine
 import io.envoyproxy.envoymobile.engine.EnvoyEngineImpl
 
-class ConfigurationException : Exception("Unresolved Template Key")
 
 open class EnvoyBuilder internal constructor(
-    private val envoyConfiguration: EnvoyConfiguration
 ) {
   private var logLevel = LogLevel.INFO
-  private var configYAML: String
+  private var configYAML: String? = null
   private var engineType: () -> EnvoyEngine = { EnvoyEngineImpl() }
 
   private var connectTimeoutSeconds = 30
   private var dnsRefreshSeconds = 60
   private var statsFlushSeconds = 60
 
-  constructor() : this(EnvoyConfigurationImpl())
-
-  init {
-    configYAML = envoyConfiguration.templateString()
-  }
-
   /**
    * Add a log level to use with Envoy.
    * @param logLevel the log level to use with Envoy.
@@ -40,7 +31,7 @@ open class EnvoyBuilder internal constructor(
    * @param configYAML the YAML file to use as a configuration.
    */
   fun addConfigYAML(configYAML: String?): EnvoyBuilder {
-    this.configYAML = configYAML ?: envoyConfiguration.templateString()
+    this.configYAML = configYAML
     return this
   }
 
@@ -80,7 +71,12 @@ open class EnvoyBuilder internal constructor(
    * @return A new instance of Envoy.
    */
   fun build(): Envoy {
-    return Envoy(engineType(), resolvedYAML(), logLevel)
+    val configurationYAML = configYAML
+    if (configurationYAML == null) {
+      return Envoy(engineType(), EnvoyConfiguration(connectTimeoutSeconds, dnsRefreshSeconds, statsFlushSeconds), logLevel)
+    } else {
+      return Envoy(engineType(), configurationYAML, logLevel)
+    }
   }
 
   /**
@@ -92,24 +88,4 @@ open class EnvoyBuilder internal constructor(
     this.engineType = engineType
     return this
   }
-
-
-  /** Processes the YAML template provided, replacing keys with values from the configuration.
-   *
-   * @parameter template: The template YAML file to use.
-   * @returns: A resolved YAML file with all template keys replaced.
-   * @throws ConfigurationException when the yaml configuration replacement is incomplete
-   */
-  private fun resolvedYAML(): String {
-    val resolvedTemplate = configYAML
-        .replace("{{ connect_timeout }}", "${connectTimeoutSeconds}s")
-        .replace("{{ dns_refresh_rate }}", "${dnsRefreshSeconds}s")
-        .replace("{{ stats_flush_interval }}", "${statsFlushSeconds}s")
-
-    if (resolvedTemplate.contains("{{")) {
-      throw ConfigurationException()
-    }
-
-    return resolvedTemplate
-  }
 }

library/kotlin/src/io/envoyproxy/envoymobile/ResponseHandler.kt

@@ -17,7 +17,7 @@ class ResponseHandler(val executor: Executor) {
     override fun getExecutor(): Executor = responseHandler.executor
 
     override fun onHeaders(headers: Map<String, List<String>>, endStream: Boolean) {
-      val statusCode = headers!![":status"]?.first()?.toIntOrNull() ?: 0
+      val statusCode = headers[":status"]?.first()?.toIntOrNull() ?: 0
       responseHandler.onHeadersClosure(headers, statusCode, endStream)
     }