Github user achristianson commented on a diff in the pull request:
https://github.com/apache/nifi-minifi-cpp/pull/134#discussion_r137886437
--- Diff: libminifi/include/core/state/metrics/MetricsBase.h ---
@@ -0,0 +1,167 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+#ifndef LIBMINIFI_INCLUDE_C2_METRICS_METRICSBASE_H_
+#define LIBMINIFI_INCLUDE_C2_METRICS_METRICSBASE_H_
+
+#include <vector>
+#include <memory>
+#include <string>
+#include "core/Core.h"
+#include "core/Connectable.h"
+
+namespace org {
+namespace apache {
+namespace nifi {
+namespace minifi {
+namespace state {
+namespace metrics {
+
+struct MetricResponse {
+ std::string name;
+ std::string value;
+ std::vector<MetricResponse> children;
+ MetricResponse &operator=(const MetricResponse &other) {
+ name = other.name;
+ value = other.value;
+ children = other.children;
+ return *this;
+ }
+};
+
+/**
+ * Purpose: Defines a metric. serialization is intended to be thread safe.
+ */
+class Metrics : public core::Connectable
+{
+ public:
+ Metrics()
+ : core::Connectable("metric", 0) {
+ }
+
+ Metrics(std::string name, uuid_t uuid)
+ : core::Connectable(name, uuid)
+ {
+ }
+ virtual ~Metrics() {
+
+ }
+ virtual std::string getName() = 0;
+
+ virtual std::vector<MetricResponse> serialize() = 0;
+
+ virtual void yield() {
+ }
+ virtual bool isRunning() {
+ return true;
+ }
+ virtual bool isWorkAvailable() {
+ return true;
+ }
+
+};
+
+/**
+ * Purpose: Defines a metric that
+ */
+class DeviceMetric : public Metrics {
+ public:
+ DeviceMetric(std::string name, uuid_t uuid)
+ : Metrics(name, uuid)
+ {
+ }
+};
+
+/**
+ * Purpose: Retrieves Metrics from the defined class. The current Metric,
which is a consumable for any reader of Metrics must have the ability to set
metrics.
+ *
+ */
+class MetricsSource
+{
+ public:
+
+ MetricsSource() {
+
+ }
+
+ virtual ~MetricsSource() {
+ }
+
+ /**
+ * Retrieves all metrics from this source.
+ * @param metric_vector -- metrics will be placed in this vector.
+ * @return result of the get operation.
+ * 0 Success
+ * 1 No error condition, but cannot obtain lock in timely manner.
+ * -1 failure
+ */
+ virtual int16_t getMetrics(std::vector<std::shared_ptr<Metrics>>
&metric_vector) = 0;
+
+};
+
+class MetricsReporter
+{
+ public:
+
+ MetricsReporter() {
+
+ }
+
+ virtual ~MetricsReporter() {
+ }
+
+ /**
+ * Retrieves all emtrics from this source.
+ * @param metric_vector -- metrics will be placed in this vector.
+ * @return result of the get operation.
+ * 0 Success
+ * 1 No error condition, but cannot obtain lock in timely manner.
+ * -1 failure
--- End diff --
E.g. E_LOCK_TIMEOUT, E_GENERAL_FAILURE, something like that (if not an
enum).
---
