Add reactive log tracing service.

Issue-ID: CCSDK-1046
Signed-off-by: Brinda Santh <bs2796@att.com>
Change-Id: Ic20013045dd5d2681243c03f9e4cdfe557b630be

2 files changed, 106 insertions, 0 deletions

diff --git a/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContext.kt b/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContext.kt
new file mode 100644
index 000000000..001ec751e
--- /dev/null
+++ b/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContext.kt
@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2018-2019 AT&T Intellectual Property.
+ *
+ * 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 org.onap.ccsdk.cds.controllerblueprints.core
+
+import kotlinx.coroutines.ThreadContextElement
+import org.slf4j.MDC
+import kotlin.coroutines.AbstractCoroutineContextElement
+import kotlin.coroutines.CoroutineContext
+
+typealias MDCContextMap = Map<String, String>?
+
+class MDCContext(private val contextMap: MDCContextMap = MDC.getCopyOfContextMap()) :
+        ThreadContextElement<MDCContextMap>, AbstractCoroutineContextElement(Key) {
+    /**
+     * Key of [MDCContext] in [CoroutineContext].
+     */
+    companion object Key : CoroutineContext.Key<MDCContext>
+
+    override fun updateThreadContext(context: CoroutineContext): MDCContextMap {
+        val oldState = MDC.getCopyOfContextMap()
+        setCurrent(contextMap)
+        return oldState
+    }
+
+    override fun restoreThreadContext(context: CoroutineContext, oldState: MDCContextMap) {
+        setCurrent(oldState)
+    }
+
+    private fun setCurrent(contextMap: MDCContextMap) {
+        if (contextMap == null) {
+            MDC.clear()
+        } else {
+            MDC.setContextMap(contextMap)
+        }
+    }
+}
\ No newline at end of file
diff --git a/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContextTest.kt b/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContextTest.kt
new file mode 100644
index 000000000..2ddb4503d
--- /dev/null
+++ b/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/MDCContextTest.kt
@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2018-2019 AT&T Intellectual Property.
+ *
+ * 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 org.onap.ccsdk.cds.controllerblueprints.core
+
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import org.junit.After
+import org.junit.Before
+import org.slf4j.MDC
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class MDCContextTest {
+    val log = logger(MDCContextTest::class)
+    @Before
+    fun setup() {
+        MDC.clear()
+    }
+
+    @After
+    fun tearDow() {
+        MDC.clear()
+    }
+
+    @Test
+    fun testContextCanBePassedBetweenCoroutines() {
+        MDC.put(BluePrintConstants.RESPONSE_HEADER_TRANSACTION_ID, "12345")
+        runBlocking {
+            GlobalScope.launch {
+                assertEquals(null, MDC.get(BluePrintConstants.RESPONSE_HEADER_TRANSACTION_ID))
+            }
+            launch(MDCContext()) {
+                assertEquals("12345", MDC.get(BluePrintConstants.RESPONSE_HEADER_TRANSACTION_ID),
+                        "couldn't get request id")
+
+                MDC.put("client_id", "client-1")
+                assertEquals("client-1", MDC.get("client_id"), "couldn't get client id")
+            }
+        }
+    }
+}
\ No newline at end of file