Implement blocking consul calls

Replaced interval based requesting for consul configuration with blocking query calls

Closes ONAP-80

Change-Id: If70365bae9fde513d99b047209d085122a5df0dd
Signed-off-by: Jakub Dudycz <jdudycz@nokia.com>
Issue-ID: DCAEGEN2-601

4 files changed, 84 insertions, 35 deletions

diff --git a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/AdapterFactory.kt b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/AdapterFactory.kt
index d9e7432d..2a8a3960 100644
--- a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/AdapterFactory.kt
+++ b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/AdapterFactory.kt
@@ -33,8 +33,8 @@ object AdapterFactory {
     fun kafkaSink(): SinkProvider = KafkaSinkProvider()
     fun loggingSink(): SinkProvider = LoggingSinkProvider()
 
-    fun consulConfigurationProvider(url: String, updateInterval: Duration): ConfigurationProvider =
-            ConsulConfigurationProvider(url, updateInterval, httpAdapter())
+    fun consulConfigurationProvider(url: String, firstRequestDelay: Duration): ConfigurationProvider =
+            ConsulConfigurationProvider(url, httpAdapter(), firstRequestDelay)
 
     fun httpAdapter(): HttpAdapter = HttpAdapter(HttpClient.create())
 }
diff --git a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/ConsulConfigurationProvider.kt b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/ConsulConfigurationProvider.kt
index c70d128a..727f025b 100644
--- a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/ConsulConfigurationProvider.kt
+++ b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/ConsulConfigurationProvider.kt
@@ -26,9 +26,14 @@ import org.onap.ves.VesEventV5.VesEvent.CommonEventHeader.Domain.HVRANMEAS
 import org.onap.ves.VesEventV5.VesEvent.CommonEventHeader.Domain.forNumber
 import org.slf4j.LoggerFactory
 import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import reactor.ipc.netty.http.client.HttpClientException
+import reactor.retry.Retry
+import reactor.retry.retryExponentialBackoff
 import java.io.StringReader
 import java.time.Duration
-import java.util.Base64
+import java.util.*
+import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicReference
 import javax.json.Json
 import javax.json.JsonObject
@@ -39,18 +44,17 @@ import javax.json.JsonObject
  * @since May 2018
  */
 internal class ConsulConfigurationProvider(private val url: String,
-                                           private val updateInterval: Duration,
-                                           private val http: HttpAdapter
+                                           private val http: HttpAdapter,
+                                           private val firstRequestDelay: Duration
 ) : ConfigurationProvider {
 
-
-    private val logger = LoggerFactory.getLogger(ConsulConfigurationProvider::class.java)
-    private var lastConfigurationHash: AtomicReference<Int> = AtomicReference()
+    private val lastModifyIndex: AtomicReference<Int> = AtomicReference(0)
+    private val lastConfigurationHash: AtomicReference<Int> = AtomicReference(0)
 
     override fun invoke(): Flux<CollectorConfiguration> =
             Flux.concat(createDefaultConfigurationFlux(), createConsulFlux())
 
-    private fun createDefaultConfigurationFlux(): Flux<CollectorConfiguration> = Flux.just(
+    private fun createDefaultConfigurationFlux(): Mono<CollectorConfiguration> = Mono.just(
             CollectorConfiguration(
                     kafkaBootstrapServers = "kafka:9092",
                     routing = routing {
@@ -60,22 +64,45 @@ internal class ConsulConfigurationProvider(private val url: String,
                             withFixedPartitioning()
                         }
                     }.build())
-    ).doOnNext { logger.info("Applied default configuration") }
-
-    private fun createConsulFlux(): Flux<CollectorConfiguration> = Flux.interval(updateInterval)
-            .flatMap { http.get(url) }
-            .doOnError { logger.error("Encountered an error when trying to acquire configuration from consul. " +
-                    "Shutting down..") }
-            .filter { it.hashCode() != lastConfigurationHash.get() }
-            .doOnNext { lastConfigurationHash.set(it.hashCode()) }
-            .map { getConfigurationJson(it) }
-            .map { createCollectorConfiguration(it) }
-
-
-    private fun getConfigurationJson(str: String): JsonObject {
-        val response = Json.createReader(StringReader(str)).readArray().getJsonObject(0)
-        val decodedValue = String(
-                Base64.getDecoder().decode(response.getString("Value")))
+    ).doOnNext { logger.info("Applied default configuration") }.delayElement(firstRequestDelay)
+
+    private fun createConsulFlux(): Flux<CollectorConfiguration> =
+            http.get(url, mapOf(Pair("index", lastModifyIndex.get())))
+                    .doOnError {
+                        logger.error("Encountered an error " +
+                                "when trying to acquire configuration from consul. Shutting down..")
+                    }
+                    .map(::parseJsonResponse)
+                    .doOnNext(::updateModifyIndex)
+                    .map(::extractEncodedConfiguration)
+                    .flatMap(::filterDifferentValues)
+                    .map(::decodeConfiguration)
+                    .map(::createCollectorConfiguration)
+                    .repeat()
+
+    private fun parseJsonResponse(responseString: String): JsonObject =
+            Json.createReader(StringReader(responseString)).readArray().first().asJsonObject()
+
+    private fun updateModifyIndex(response: JsonObject) =
+            lastModifyIndex.set(response.getInt("ModifyIndex"))
+
+    private fun extractEncodedConfiguration(response: JsonObject): String =
+            response.getString("Value")
+
+    private fun filterDifferentValues(base64Value: String): Mono<String> {
+        val newHash = hashOf(base64Value)
+        return if (newHash == lastConfigurationHash.get()) {
+            Mono.empty()
+        } else {
+            lastConfigurationHash.set(newHash)
+            Mono.just(base64Value)
+        }
+    }
+
+    private fun hashOf(str: String) = str.hashCode()
+
+    private fun decodeConfiguration(encodedConfiguration: String): JsonObject {
+        val decodedValue = String(Base64.getDecoder().decode(encodedConfiguration))
         logger.info("Obtained new configuration from consul:\n$decodedValue")
         return Json.createReader(StringReader(decodedValue)).readObject()
     }
@@ -97,5 +124,9 @@ internal class ConsulConfigurationProvider(private val url: String,
                 }.build()
         )
     }
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(ConsulConfigurationProvider::class.java)
+    }
 }
 
diff --git a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/HttpAdapter.kt b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/HttpAdapter.kt
index a41cd09f..4503955f 100644
--- a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/HttpAdapter.kt
+++ b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/impl/adapters/HttpAdapter.kt
@@ -23,7 +23,6 @@ import org.slf4j.LoggerFactory
 import reactor.core.publisher.Mono
 import reactor.core.publisher.toMono
 import reactor.ipc.netty.http.client.HttpClient
-import reactor.ipc.netty.http.client.HttpClientResponse
 import java.nio.charset.Charset
 
 /**
@@ -34,12 +33,31 @@ open class HttpAdapter(private val httpClient: HttpClient) {
 
     private val logger = LoggerFactory.getLogger(HttpAdapter::class.java)
 
-    open fun get(url: String): Mono<String> =
-            httpClient.get(url)
-                    .doOnError {
-                        logger.error("Failed to get resource on path: $url (${it.localizedMessage})")
-                        logger.debug("Nested exception:", it)
-                    }
-                    .flatMap { it.receiveContent().toMono() }
-                    .map { it.content().toString(Charset.defaultCharset()) }
+    open fun get(url: String, queryParams: Map<String, Any> = emptyMap()): Mono<String> = httpClient
+            .get(url + createQueryString(queryParams))
+            .doOnError {
+                logger.error("Failed to get resource on path: $url (${it.localizedMessage})")
+                logger.debug("Nested exception:", it)
+            }
+            .flatMap { it.receiveContent().toMono() }
+            .map { it.content().toString(Charset.defaultCharset()) }
+
+
+    private fun createQueryString(params: Map<String, Any>): String {
+        if (params.isEmpty())
+            return ""
+
+        val builder = StringBuilder("?")
+        params.forEach { (key, value) ->
+            builder
+                    .append(key)
+                    .append("=")
+                    .append(value)
+                    .append("&")
+
+        }
+
+        return  builder.removeSuffix("&").toString()
+    }
+
 }
diff --git a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/model/ServerConfiguration.kt b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/model/ServerConfiguration.kt
index 025c59f6..a486996e 100644
--- a/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/model/ServerConfiguration.kt
+++ b/hv-collector-core/src/main/kotlin/org/onap/dcae/collectors/veshv/model/ServerConfiguration.kt
@@ -29,7 +29,7 @@ import java.time.Duration
 data class ServerConfiguration(
         val port: Int,
         val configurationUrl: String,
-        val configurationUpdateInterval: Duration,
+        val firstRequestDelay: Duration,
         val securityConfiguration: SecurityConfiguration,
         val idleTimeout: Duration,
         val dummyMode: Boolean = false)