add kotlin client lib (#1)

Author: asurkov

kotlin/build.gradle

@@ -0,0 +1,52 @@
+// Copyright 2018 Sourcerer Inc. All Rights Reserved.
+
+buildscript {
+    ext {
+        kotlin_version = '1.1.51'
+    }
+    repositories {
+        mavenCentral()
+        jcenter()
+    }
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.junit.platform:junit-platform-gradle-plugin:1.0.1"
+    }
+}
+
+apply plugin: "idea"
+apply plugin: "java"
+apply plugin: "kotlin"
+apply plugin: "application"
+apply plugin: "org.junit.platform.gradle.plugin"
+
+sourceSets {
+    main.java.srcDirs += 'src/'
+}
+
+junitPlatform {
+    filters {
+        engines {
+            include 'spek'
+        }
+    }
+}
+
+mainClassName = "LogEvent"
+
+repositories {
+    mavenCentral()
+    jcenter()
+    maven { url "http://dl.bintray.com/jetbrains/spek" }
+}
+
+dependencies {
+    compile "org.jetbrains.kotlin:kotlin-stdlib-jre8:$kotlin_version"
+    compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
+    compile 'com.github.kittinunf.fuel:fuel:1.11.0'
+
+    testCompile 'org.jetbrains.kotlin:kotlin-test'
+    testCompile 'org.jetbrains.spek:spek-api:1.1.5'
+    testCompile 'org.junit.platform:junit-platform-runner:1.0.1'
+    testRuntime 'org.jetbrains.spek:spek-junit-platform-engine:1.1.5'
+}

kotlin/src/LogEvent.kt

@@ -0,0 +1,77 @@
+// Copyright 2018 Sourcerer Inc. All Rights Reserved.
+// Author: Alexander Surkov ([email protected])
+
+package sourcererio.vacuumanalytics
+
+import com.github.kittinunf.fuel.core.FuelError
+import com.github.kittinunf.fuel.core.FuelManager
+import com.github.kittinunf.fuel.core.Method
+import com.github.kittinunf.fuel.core.Request
+import com.github.kittinunf.fuel.core.Response
+import java.net.HttpCookie
+import java.util.Date
+
+/**
+ * Elastic LogStash logging.
+ */
+class LogEvent {
+    // Unique identifier of the session.
+    private var session: String = ""
+
+    private val fuelManager = FuelManager()
+
+    /**
+     * Creates a LogEvent instance.
+     *
+     * @param path [in] path to send logs to,
+     * @param res  [in] HTTP response of successful user authorization,
+     * @param sid  [in] session id of the HTTP response.
+     */
+    constructor(path: String,
+                res: Response, sid: String) {
+        res.headers["Set-Cookie"]?.
+            flatMap { HttpCookie.parse(it) }?.
+            find { it.name == sid }?.
+            let { session = it.value }
+
+        fuelManager.basePath = path
+    }
+
+    /**
+     * Logs error.
+     */
+    fun error(message: String) {
+        event("error", message)
+    }
+
+    /**
+     * Logs event.
+     */
+    fun event(type: String, message: String) {
+        event(type, listOf("message" to message))
+    }
+
+    /**
+     * Logs event.
+     */
+    fun event(type: String, fields: List<Pair<String, Any?>>) {
+        var params = mutableListOf<Pair<String, Any?>>(
+            "session" to session,
+            "type" to type,
+            "timestamp" to Date().getTime()
+        )
+
+        fuelManager.
+            request(
+                Method.POST,
+                "",
+                params.plus(fields)
+            )
+            .response { _, _, result ->
+                val (_, err) = result
+                if (err != null) {
+                    throw Exception("FAILED to send logs: $err")
+                }
+            }
+    }
+}