com.nextdoor.bender.operation.gelf.GelfOperation.java Source code

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Here is the source code for com.nextdoor.bender.operation.gelf.GelfOperation.java

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/*
 * 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.
 *
 * Copyright 2018 Nextdoor.com, Inc
 *
 */

package com.nextdoor.bender.operation.gelf;

import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;
import com.nextdoor.bender.InternalEvent;
import com.nextdoor.bender.deserializer.DeserializedEvent;
import com.nextdoor.bender.operation.EventOperation;
import com.nextdoor.bender.operation.OperationException;
import com.nextdoor.bender.operation.json.key.FlattenOperation;
import com.nextdoor.bender.operation.substitution.Substitution;
import com.nextdoor.bender.operation.substitution.SubstitutionOperation;
import com.nextdoor.bender.time.TimeOperation;

public class GelfOperation implements EventOperation {

    private final FlattenOperation flattenOp;
    private final SubstitutionOperation subOp;

    private static final Set<String> GELF_FIELDS = new HashSet<>(Arrays.asList("version", "host", "short_message",
            "full_message", "timestamp", "level", "facility", "line", "file"));

    public GelfOperation(List<Substitution> substitutions) {
        this.subOp = new SubstitutionOperation(substitutions);
        this.flattenOp = new FlattenOperation(".");
    }

    protected InternalEvent prefix(InternalEvent ievent) {
        DeserializedEvent devent;
        if ((devent = ievent.getEventObj()) == null) {
            return null;
        }

        Object payload = devent.getPayload();

        if (payload == null) {
            return null;
        }

        if (!(payload instanceof JsonObject)) {
            throw new OperationException("Payload data is not a JsonObject");
        }

        JsonObject obj = (JsonObject) payload;

        Set<Entry<String, JsonElement>> entries = obj.entrySet();
        Set<Entry<String, JsonElement>> orgEntries = new HashSet<Entry<String, JsonElement>>(entries);

        /*
         * Prefix additional fields with "_". Everything that is not a GELF field is additional.
         */
        for (Entry<String, JsonElement> entry : orgEntries) {
            String key = entry.getKey();

            if (GELF_FIELDS.contains(key)) {
                continue;
            }

            JsonElement val = entry.getValue();
            obj.remove(key);

            obj.add("_" + key, val);
        }

        return ievent;
    }

    /**
     * Parses through the internal JSON Deserialized Event and optionally adds a "timestamp" key.
     *
     * If the "timestamp" key already exists, this method does nothing and bails out. If there
     * is no "timestamp" key, and either the EventTime or ArrivalTime of the {@link InternalEvent}
     * have been set (presumably by the {@link TimeOperation}), then these are used to set the
     * "timestamp" key in the object.
     *
     * @param ievent
     * @return {@link InternalEvent}
     */
    protected InternalEvent setTimestamp(InternalEvent ievent) {
        DeserializedEvent devent;
        if ((devent = ievent.getEventObj()) == null) {
            return null;
        }

        Object payload = devent.getPayload();

        if (payload == null) {
            return null;
        }

        JsonObject obj = (JsonObject) payload;

        if (obj.has("timestamp")) {
            return ievent;
        }

        double timestamp;
        if (ievent.getEventTime() > 1) {
            timestamp = ievent.getEventTime() / 1000.0;
        } else {
            return ievent;
        }

        obj.add("timestamp", new JsonPrimitive(timestamp));

        return ievent;
    }

    public InternalEvent perform(InternalEvent ievent) {
        /*
         * Substitute
         */
        ievent = subOp.perform(ievent);

        /*
         * Flatten
         */
        ievent = flattenOp.perform(ievent);

        /*
         * Prefix
         */
        ievent = prefix(ievent);

        /*
         * Rewrite the timestamp field from the Internal Event time
         */
        ievent = setTimestamp(ievent);

        return ievent;
    }
}