JsonFormatterTest.java

/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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.
 */
package com.google.apphosting.logging;

import java.io.BufferedReader;
import java.io.StringReader;
import java.util.Collections;
import java.util.logging.Level;
import java.util.logging.LogRecord;

import org.junit.Test;

import com.google.gson.Gson;
import static org.hamcrest.core.StringEndsWith.endsWith;
import static org.junit.Assert.*;

public class JsonFormatterTest {

    private JsonFormatter formatter = new JsonFormatter();

    @Test
    public void formatProducesExpectedJsonData() throws Exception {
        LogRecord record = new LogRecord(Level.INFO, "message");
        record.setMillis(12345_678);
        record.setLoggerName("logger");
        LogContext context = new LogContext(Collections.singletonMap("traceId", "abcdef"));

        String logLine = context.execute(() -> formatter.format(record));
        assertThat(logLine, endsWith(System.lineSeparator()));

        JsonData data = new Gson().fromJson(logLine, JsonData.class);
        assertEquals("INFO", data.severity);
        assertEquals(12345, data.timestamp.seconds);
        assertEquals(678_000_000, data.timestamp.nanos);
        assertEquals(Thread.currentThread().getName(), data.thread);
        assertEquals("logger: message", data.message);
        assertEquals("abcdef", data.traceId);
    }

    @Test
    public void messageIncludesLoggerName() throws Exception {
        LogRecord record = new LogRecord(Level.INFO, "message");
        record.setLoggerName("logger");
        assertEquals("logger: message", formatter.formatMessage(record));
    }

    @Test
    public void messageIncludesClassName() throws Exception {
        LogRecord record = new LogRecord(Level.INFO, "message");
        record.setSourceClassName("class");
        record.setLoggerName("logger");
        assertEquals("class: message", formatter.formatMessage(record));
    }

    @Test
    public void messageIncludesMethodName() throws Exception {
        LogRecord record = new LogRecord(Level.INFO, "message");
        record.setSourceClassName("class");
        record.setSourceMethodName("method");
        assertEquals("class method: message", formatter.formatMessage(record));
    }

    @Test
    public void messageIncludesStackTrace() throws Exception {
        LogRecord record = new LogRecord(Level.INFO, "message");
        record.setLoggerName("logger");
        record.setThrown(new Throwable("thrown").fillInStackTrace());
        String message = formatter.formatMessage(record);
        BufferedReader reader = new BufferedReader(new StringReader(message));
        assertEquals("logger: message", reader.readLine());
        assertEquals("java.lang.Throwable: thrown", reader.readLine());
        assertTrue(reader.readLine()
                .startsWith("\tat " + getClass().getName() + ".messageIncludesStackTrace"));
    }

    // Something that JSON can parser the JSON into
    public static class JsonData {
        public static class LogTimestamp {
            public long seconds;
            public long nanos;
        }
        public LogTimestamp timestamp;
        public String severity;
        public String thread;
        public String message;
        public String traceId;
    }
}