From 13f87299a11f14333268670a3d677358ebf2d178 Mon Sep 17 00:00:00 2001
From: Ivan Topolnjak <ivantopo@gmail.com>
Date: Fri, 6 Apr 2018 01:47:40 +0200
Subject: add the EnvironmentTagBuilder utility class

---
 .../kamon/util/EnvironmentTagBuilderSpec.scala     | 104 +++++++++++++++++++++
 .../scala/kamon/util/EnvironmentTagBuilder.scala   |  43 +++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 kamon-core-tests/src/test/scala/kamon/util/EnvironmentTagBuilderSpec.scala
 create mode 100644 kamon-core/src/main/scala/kamon/util/EnvironmentTagBuilder.scala

diff --git a/kamon-core-tests/src/test/scala/kamon/util/EnvironmentTagBuilderSpec.scala b/kamon-core-tests/src/test/scala/kamon/util/EnvironmentTagBuilderSpec.scala
new file mode 100644
index 00000000..5b7d6262
--- /dev/null
+++ b/kamon-core-tests/src/test/scala/kamon/util/EnvironmentTagBuilderSpec.scala
@@ -0,0 +1,104 @@
+/* =========================================================================================
+ * Copyright © 2013-2017 the kamon project <http://kamon.io/>
+ *
+ * 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 kamon
+package util
+
+import com.typesafe.config.ConfigFactory
+import org.scalatest.{Matchers, WordSpec}
+
+class EnvironmentTagBuilderSpec extends WordSpec with Matchers {
+  private val testEnv = Environment.fromConfig(ConfigFactory.parseString(
+    """
+      |kamon.environment {
+      |  service = environment-spec
+      |  host = my-hostname
+      |  instance = my-instance-name
+      |
+      |  tags {
+      |    env = staging
+      |    region = asia-1
+      |  }
+      |}
+    """.stripMargin
+  ).withFallback(ConfigFactory.defaultReference()))
+
+  "the EnvironmentTagBuilder" should {
+
+    "build the tags from a configuration using the current Environment" in {
+      val config = ConfigFactory.parseString(
+        """
+          |service = yes
+          |host = yes
+          |instance = yes
+          |blacklisted-tags = []
+        """.stripMargin)
+
+      val env = Kamon.environment
+      val tags = EnvironmentTagBuilder.create(config)
+      tags("service") shouldBe env.service
+      tags("host") shouldBe env.host
+      tags("instance") shouldBe env.instance
+    }
+
+    "build tags from a custom Environment" in {
+      val config = ConfigFactory.parseString(
+        """
+          |service = yes
+          |host = yes
+          |instance = yes
+          |blacklisted-tags = []
+        """.stripMargin)
+
+      val tags = EnvironmentTagBuilder.create(testEnv, config)
+      tags("service") shouldBe testEnv.service
+      tags("host") shouldBe testEnv.host
+      tags("instance") shouldBe testEnv.instance
+      tags("env") shouldBe "staging"
+      tags("region") shouldBe "asia-1"
+
+    }
+
+    "remove blacklisted tags" in {
+      val config = ConfigFactory.parseString(
+        """
+          |service = yes
+          |host = yes
+          |instance = yes
+          |blacklisted-tags = [ "region" ]
+        """.stripMargin)
+
+      val tags = EnvironmentTagBuilder.create(testEnv, config)
+      tags("service") shouldBe testEnv.service
+      tags("host") shouldBe testEnv.host
+      tags("instance") shouldBe testEnv.instance
+      tags("env") shouldBe "staging"
+      tags.get("region") shouldBe empty
+    }
+
+    "remove all disabled elements" in {
+      val config = ConfigFactory.parseString(
+        """
+          |service = no
+          |host = no
+          |instance = no
+          |blacklisted-tags = [ "region", "env" ]
+        """.stripMargin)
+
+      val tags = EnvironmentTagBuilder.create(testEnv, config)
+      tags shouldBe empty
+    }
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/util/EnvironmentTagBuilder.scala b/kamon-core/src/main/scala/kamon/util/EnvironmentTagBuilder.scala
new file mode 100644
index 00000000..09e643e9
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/util/EnvironmentTagBuilder.scala
@@ -0,0 +1,43 @@
+package kamon.util
+
+import com.typesafe.config.Config
+import kamon.{Environment, Kamon}
+
+import scala.collection.JavaConverters._
+
+
+/**
+  *   Utility class to create a Map[String, String] encoding all the Environment information based on the provided
+  *   Config. The Config instance is expected to have the following members:
+  *
+  *     - service:          Boolean. If true a service tag is included.
+  *     - host:             Boolean. If true a host tag is included.
+  *     - instance:         Boolean. If true a instance tag is included.
+  *     - blacklisted-tags: List[String]. List of Environment tags that should not be included in the result.
+  *
+  *   This utility is meant to be used mostly by reporter modules.
+  *
+  */
+object EnvironmentTagBuilder {
+
+  def create(config: Config): Map[String, String] =
+    create(Kamon.environment, config)
+
+  def create(env: Environment, config: Config): Map[String, String] = {
+    val envTags = Map.newBuilder[String, String]
+
+    if(config.getBoolean("service"))
+      envTags += ("service" -> env.service)
+
+    if(config.getBoolean("host"))
+      envTags += ("host" -> env.host)
+
+    if(config.getBoolean("instance"))
+      envTags += ("instance" -> env.instance)
+
+    val blacklistedTags = config.getStringList("blacklisted-tags").asScala
+    env.tags.filterKeys(k => !blacklistedTags.contains(k)).foreach(p => envTags += p)
+
+    envTags.result()
+  }
+}
-- 
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