controllers.MetaController.java Source code

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Here is the source code for controllers.MetaController.java

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/**
 * Copyright 2014 Brandon Arp
 *
 * 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 controllers;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.typesafe.config.ConfigValue;
import play.Configuration;
import play.mvc.Controller;
import play.mvc.Result;

import java.util.ArrayList;
import java.util.Map;
import javax.inject.Singleton;

/**
 * Metrics portal generic Play controller.
 *
 * @author Brandon Arp (brandonarp at gmail dot com)
 */
@Singleton
public final class MetaController extends Controller {

    /**
     * Endpoint implementation to dump Play application configuration.
     *
     * @return Serialized response containing configuration.
     */
    public Result config() {
        final JsonNode node = getConfigNode(play.Configuration.root());
        return ok(node);
    }

    /**
     * Endpoint implementation to retrieve service health as JSON.
     *
     * @return Serialized response containing service health.
     */
    public Result ping() {
        final boolean healthy = isHealthy();
        final ObjectNode result = JsonNodeFactory.instance.objectNode();
        response().setHeader(CACHE_CONTROL, "private, no-cache, no-store, must-revalidate");
        if (healthy) {
            result.put("status", HEALTHY_STATE);
            return ok(result);
        }
        result.put("status", UNHEALTHY_STATE);
        return internalServerError(result);
    }

    private static boolean isHealthy() {
        // TODO(vkoskela): Deep health check when features warrant it [MAI-83].
        return Boolean.TRUE;
    }

    // TODO(vkoskela): Convert this to a JSON serializer [MAI-65]
    private static JsonNode getConfigNode(final Object element) {
        if (element instanceof Configuration) {
            final Configuration config = (Configuration) element;
            final ObjectNode node = JsonNodeFactory.instance.objectNode();
            for (final Map.Entry<String, ConfigValue> entry : config.entrySet()) {
                put(node, entry.getKey(), entry.getValue());
            }
            return node;
        } else if (element instanceof String) {
            final String config = (String) element;
            return JsonNodeFactory.instance.textNode(config);
        } else if (element instanceof Integer) {
            final Integer integer = (Integer) element;
            return JsonNodeFactory.instance.numberNode(integer);
        } else if (element instanceof Double) {
            final Double d = (Double) element;
            return JsonNodeFactory.instance.numberNode(d);
        } else if (element instanceof ArrayList) {
            final ArrayNode arr = JsonNodeFactory.instance.arrayNode();
            @SuppressWarnings("unchecked")
            final ArrayList<Object> list = (ArrayList<Object>) element;
            for (final Object o : list) {
                arr.add(getConfigNode(o));
            }
            return arr;
        }
        return JsonNodeFactory.instance.textNode("UNKNOWN TYPE: " + element.getClass().getCanonicalName());
    }

    // TODO(vkoskela): Convert this to a JSON serializer [MAI-65]
    private static void put(final ObjectNode node, final String remaining, final ConfigValue value) {
        final int dotIndex = remaining.indexOf('.');
        final boolean leaf = dotIndex == -1;
        if (leaf) {
            node.set(remaining, getConfigNode(value.unwrapped()));
        } else {
            final String firstChunk = remaining.substring(0, dotIndex);
            ObjectNode child = (ObjectNode) node.get(firstChunk);
            if (child == null || child.isNull()) {
                child = JsonNodeFactory.instance.objectNode();
                node.set(firstChunk, child);
            }
            put(child, remaining.substring(dotIndex + 1), value);
        }
    }

    private static final String UNHEALTHY_STATE = "UNHEALTHY";
    private static final String HEALTHY_STATE = "HEALTHY";
}