Read config from environment variables

The application configuration should be read from command line options
as well as from environment variables. The priority: cmd-line over env
over defaults.

Change-Id: I785fd1fbaf66f3eab84a162f037153f1688ed791
Issue-ID: DCAEGEN2-748
Signed-off-by: Piotr Jaszczyk <piotr.jaszczyk@nokia.com>

2 files changed, 143 insertions, 2 deletions

diff --git a/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/CoreKtTest.kt b/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/CoreKtTest.kt
index 585851be..29359439 100644
--- a/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/CoreKtTest.kt
+++ b/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/arrow/CoreKtTest.kt
@@ -20,6 +20,7 @@
 package org.onap.dcae.collectors.veshv.utils.arrow
 
 import arrow.core.None
+import arrow.core.Option
 import arrow.core.Some
 import org.assertj.core.api.Assertions.assertThat
 import org.jetbrains.spek.api.Spek
@@ -27,6 +28,7 @@ import org.jetbrains.spek.api.dsl.describe
 import org.jetbrains.spek.api.dsl.given
 import org.jetbrains.spek.api.dsl.it
 import org.jetbrains.spek.api.dsl.on
+import org.jetbrains.spek.api.dsl.xdescribe
 import java.util.concurrent.atomic.AtomicReference
 
 
@@ -34,7 +36,7 @@ import java.util.concurrent.atomic.AtomicReference
  * @author Piotr Jaszczyk <piotr.jaszczyk></piotr.jaszczyk>@nokia.com>
  * @since August 2018
  */
-internal class CoreKtTest: Spek({
+internal class CoreKtTest : Spek({
     describe("AtomicReference.getOption") {
         given("empty atomic reference") {
             val atomicReference = AtomicReference<String>()
@@ -60,4 +62,81 @@ internal class CoreKtTest: Spek({
             }
         }
     }
-})
\ No newline at end of file
+
+    describe("Option.fromNullablesChain") {
+        given("one non-null element") {
+            val just = "some text"
+            on("calling factory") {
+                val result = Option.fromNullablesChain(just)
+
+                it("should return Some($just)") {
+                    assertThat(result).isEqualTo(Some(just))
+                }
+            }
+        }
+
+        given("one null element") {
+            val just: String? = null
+            on("calling factory") {
+                val result = Option.fromNullablesChain(just)
+
+                it("should return None") {
+                    assertThat(result).isEqualTo(None)
+                }
+            }
+        }
+
+        given("first non-null element") {
+            val first = "some text"
+            val second: String? = null
+            var secondAskedForValue = false
+            on("calling factory") {
+                val result = Option.fromNullablesChain(first, { secondAskedForValue = true; second })
+
+                it("should return Some($first)") {
+                    assertThat(result).isEqualTo(Some(first))
+                }
+
+                it("should have not called second provider (should be lazy)") {
+                    assertThat(secondAskedForValue).isFalse()
+                }
+            }
+        }
+
+        given("two non-null elements") {
+            val first = "some text"
+            val second = "another text"
+            on("calling factory") {
+                val result = Option.fromNullablesChain(first, { second })
+
+                it("should return Some($first)") {
+                    assertThat(result).isEqualTo(Some(first))
+                }
+            }
+        }
+
+        given("two null elements") {
+            val first: String? = null
+            val second: String? = null
+            on("calling factory") {
+                val result = Option.fromNullablesChain(first, { second })
+
+                it("should return None") {
+                    assertThat(result).isEqualTo(None)
+                }
+            }
+        }
+
+        given("second non-null element") {
+            val first: String? = null
+            val second = "another text"
+            on("calling factory") {
+                val result = Option.fromNullablesChain(first, { second })
+
+                it("should return Some($second)") {
+                    assertThat(result).isEqualTo(Some(second))
+                }
+            }
+        }
+    }
+})
diff --git a/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/commandline/CommandLineOptionTest.kt b/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/commandline/CommandLineOptionTest.kt
new file mode 100644
index 00000000..f36df043
--- /dev/null
+++ b/hv-collector-utils/src/test/kotlin/org/onap/dcae/collectors/veshv/utils/commandline/CommandLineOptionTest.kt
@@ -0,0 +1,62 @@
+/*
+ * ============LICENSE_START=======================================================
+ * dcaegen2-collectors-veshv
+ * ================================================================================
+ * Copyright (C) 2018 NOKIA
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.collectors.veshv.utils.commandline
+
+import org.assertj.core.api.Assertions.assertThat
+import org.jetbrains.spek.api.Spek
+import org.jetbrains.spek.api.dsl.describe
+import org.jetbrains.spek.api.dsl.given
+import org.jetbrains.spek.api.dsl.it
+import org.jetbrains.spek.api.dsl.on
+
+/**
+ * @author Piotr Jaszczyk <piotr.jaszczyk@nokia.com>
+ * @since September 2018
+ */
+class CommandLineOptionTest : Spek({
+    describe("command line options enum") {
+        describe("environment variables") {
+            given("sample option and prefix") {
+                val opt = CommandLineOption.KAFKA_SERVERS
+                val prefix = "CONFIG"
+
+                on("calling environmentVariableName") {
+                    val result = opt.environmentVariableName(prefix)
+
+                    it("should return prefixed upper snake cased long option name") {
+                        assertThat(result).isEqualTo("CONFIG_KAFKA_BOOTSTRAP_SERVERS")
+                    }
+                }
+            }
+
+            given("sample option without prefix") {
+                val opt = CommandLineOption.DUMMY_MODE
+
+                on("calling environmentVariableName") {
+                    val result = opt.environmentVariableName()
+
+                    it("should return prefixed upper snake cased long option name") {
+                        assertThat(result).isEqualTo("VESHV_DUMMY")
+                    }
+                }
+            }
+        }
+    }
+})