/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.
*/
package org.elasticsearch.common.logging;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.Build;
import org.elasticsearch.Version;
import org.elasticsearch.common.SuppressLoggerChecks;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.SignStyle;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.DAY_OF_WEEK;
import static java.time.temporal.ChronoField.HOUR_OF_DAY;
import static java.time.temporal.ChronoField.MINUTE_OF_HOUR;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
import static java.time.temporal.ChronoField.YEAR;
/**
* A logger that logs deprecation notices.
*/
public class DeprecationLogger {
private final Logger logger;
/**
* This is set once by the {@code Node} constructor, but it uses {@link CopyOnWriteArraySet} to ensure that tests can run in parallel.
* <p>
* Integration tests will create separate nodes within the same classloader, thus leading to a shared, {@code static} state.
* In order for all tests to appropriately be handled, this must be able to remember <em>all</em> {@link ThreadContext}s that it is
* given in a thread safe manner.
* <p>
* For actual usage, multiple nodes do not share the same JVM and therefore this will only be set once in practice.
*/
private static final CopyOnWriteArraySet<ThreadContext> THREAD_CONTEXT = new CopyOnWriteArraySet<>();
/**
* Set the {@link ThreadContext} used to add deprecation headers to network responses.
* <p>
* This is expected to <em>only</em> be invoked by the {@code Node}'s constructor (therefore once outside of tests).
*
* @param threadContext The thread context owned by the {@code ThreadPool} (and implicitly a {@code Node})
* @throws IllegalStateException if this {@code threadContext} has already been set
*/
public static void setThreadContext(ThreadContext threadContext) {
Objects.requireNonNull(threadContext, "Cannot register a null ThreadContext");
// add returning false means it _did_ have it already
if (THREAD_CONTEXT.add(threadContext) == false) {
throw new IllegalStateException("Double-setting ThreadContext not allowed!");
}
}
/**
* Remove the {@link ThreadContext} used to add deprecation headers to network responses.
* <p>
* This is expected to <em>only</em> be invoked by the {@code Node}'s {@code close} method (therefore once outside of tests).
*
* @param threadContext The thread context owned by the {@code ThreadPool} (and implicitly a {@code Node})
* @throws IllegalStateException if this {@code threadContext} is unknown (and presumably already unset before)
*/
public static void removeThreadContext(ThreadContext threadContext) {
assert threadContext != null;
// remove returning false means it did not have it already
if (THREAD_CONTEXT.remove(threadContext) == false) {
throw new IllegalStateException("Removing unknown ThreadContext not allowed!");
}
}
/**
* Creates a new deprecation logger based on the parent logger. Automatically
* prefixes the logger name with "deprecation", if it starts with "org.elasticsearch.",
* it replaces "org.elasticsearch" with "org.elasticsearch.deprecation" to maintain
* the "org.elasticsearch" namespace.
*/
public DeprecationLogger(Logger parentLogger) {
String name = parentLogger.getName();
if (name.startsWith("org.elasticsearch")) {
name = name.replace("org.elasticsearch.", "org.elasticsearch.deprecation.");
} else {
name = "deprecation." + name;
}
this.logger = LogManager.getLogger(name);
}
/**
* Logs a deprecated message.
*/
public void deprecated(String msg, Object... params) {
deprecated(THREAD_CONTEXT, msg, params);
}
/*
* RFC7234 specifies the warning format as warn-code <space> warn-agent <space> "warn-text" [<space> "warn-date"]. Here, warn-code is a
* three-digit number with various standard warn codes specified. The warn code 299 is apt for our purposes as it represents a
* miscellaneous persistent warning (can be presented to a human, or logged, and must not be removed by a cache). The warn-agent is an
* arbitrary token; here we use the Elasticsearch version and build hash. The warn text must be quoted. The warn-date is an optional
* quoted field that can be in a variety of specified date formats; here we use RFC 1123 format.
*/
private static final String WARNING_FORMAT =
String.format(
Locale.ROOT,
"299 Elasticsearch-%s%s-%s ",
Version.CURRENT.toString(),
Build.CURRENT.isSnapshot() ? "-SNAPSHOT" : "",
Build.CURRENT.shortHash()) +
"\"%s\" \"%s\"";
/*
* RFC 7234 section 5.5 specifies that the warn-date is a quoted HTTP-date. HTTP-date is defined in RFC 7234 Appendix B as being from
* RFC 7231 section 7.1.1.1. RFC 7231 specifies an HTTP-date as an IMF-fixdate (or an obs-date referring to obsolete formats). The
* grammar for IMF-fixdate is specified as 'day-name "," SP date1 SP time-of-day SP GMT'. Here, day-name is
* (Mon|Tue|Wed|Thu|Fri|Sat|Sun). Then, date1 is 'day SP month SP year' where day is 2DIGIT, month is
* (Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec), and year is 4DIGIT. Lastly, time-of-day is 'hour ":" minute ":" second' where
* hour is 2DIGIT, minute is 2DIGIT, and second is 2DIGIT. Finally, 2DIGIT and 4DIGIT have the obvious definitions.
*/
private static final DateTimeFormatter RFC_7231_DATE_TIME;
static {
final Map<Long, String> dow = new HashMap<>();
dow.put(1L, "Mon");
dow.put(2L, "Tue");
dow.put(3L, "Wed");
dow.put(4L, "Thu");
dow.put(5L, "Fri");
dow.put(6L, "Sat");
dow.put(7L, "Sun");
final Map<Long, String> moy = new HashMap<>();
moy.put(1L, "Jan");
moy.put(2L, "Feb");
moy.put(3L, "Mar");
moy.put(4L, "Apr");
moy.put(5L, "May");
moy.put(6L, "Jun");
moy.put(7L, "Jul");
moy.put(8L, "Aug");
moy.put(9L, "Sep");
moy.put(10L, "Oct");
moy.put(11L, "Nov");
moy.put(12L, "Dec");
RFC_7231_DATE_TIME = new DateTimeFormatterBuilder()
.parseCaseInsensitive()
.parseLenient()
.optionalStart()
.appendText(DAY_OF_WEEK, dow)
.appendLiteral(", ")
.optionalEnd()
.appendValue(DAY_OF_MONTH, 2, 2, SignStyle.NOT_NEGATIVE)
.appendLiteral(' ')
.appendText(MONTH_OF_YEAR, moy)
.appendLiteral(' ')
.appendValue(YEAR, 4)
.appendLiteral(' ')
.appendValue(HOUR_OF_DAY, 2)
.appendLiteral(':')
.appendValue(MINUTE_OF_HOUR, 2)
.optionalStart()
.appendLiteral(':')
.appendValue(SECOND_OF_MINUTE, 2)
.optionalEnd()
.appendLiteral(' ')
.appendOffset("+HHMM", "GMT")
.toFormatter(Locale.getDefault(Locale.Category.FORMAT));
}
private static final ZoneId GMT = ZoneId.of("GMT");
/**
* Regular expression to test if a string matches the RFC7234 specification for warning headers. This pattern assumes that the warn code
* is always 299. Further, this pattern assumes that the warn agent represents a version of Elasticsearch including the build hash.
*/
public static Pattern WARNING_HEADER_PATTERN = Pattern.compile(
"299 " + // warn code
"Elasticsearch-\\d+\\.\\d+\\.\\d+(?:-(?:alpha|beta|rc)\\d+)?(?:-SNAPSHOT)?-(?:[a-f0-9]{7}|Unknown) " + // warn agent
"\"((?:\t| |!|[\\x23-\\x5b]|[\\x5d-\\x7e]|[\\x80-\\xff]|\\\\|\\\\\")*)\" " + // quoted warning value, captured
// quoted RFC 1123 date format
"\"" + // opening quote
"(?:Mon|Tue|Wed|Thu|Fri|Sat|Sun), " + // weekday
"\\d{2} " + // 2-digit day
"(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec) " + // month
"\\d{4} " + // 4-digit year
"\\d{2}:\\d{2}:\\d{2} " + // (two-digit hour):(two-digit minute):(two-digit second)
"GMT" + // GMT
"\""); // closing quote
/**
* Extracts the warning value from the value of a warning header that is formatted according to RFC 7234. That is, given a string
* {@code 299 Elasticsearch-6.0.0 "warning value" "Sat, 25 Feb 2017 10:27:43 GMT"}, the return value of this method would be {@code
* warning value}.
*
* @param s the value of a warning header formatted according to RFC 7234.
* @return the extracted warning value
*/
public static String extractWarningValueFromWarningHeader(final String s) {
/*
* We know the exact format of the warning header, so to extract the warning value we can skip forward from the front to the first
* quote, and skip backwards from the end to the penultimate quote:
*
* 299 Elasticsearch-6.0.0 "warning value" "Sat, 25, Feb 2017 10:27:43 GMT"
* ^ ^ ^
* firstQuote penultimateQuote lastQuote
*
* We do it this way rather than seeking forward after the first quote because there could be escaped quotes in the warning value
* but since there are none in the warning date, we can skip backwards to find the quote that closes the quoted warning value.
*
* We parse this manually rather than using the capturing regular expression because the regular expression involves a lot of
* backtracking and carries a performance penalty. However, when assertions are enabled, we still use the regular expression to
* verify that we are maintaining the warning header format.
*/
final int firstQuote = s.indexOf('\"');
final int lastQuote = s.lastIndexOf('\"');
final int penultimateQuote = s.lastIndexOf('\"', lastQuote - 1);
final String warningValue = s.substring(firstQuote + 1, penultimateQuote - 2);
assert assertWarningValue(s, warningValue);
return warningValue;
}
/**
* Assert that the specified string has the warning value equal to the provided warning value.
*
* @param s the string representing a full warning header
* @param warningValue the expected warning header
* @return {@code true} if the specified string has the expected warning value
*/
private static boolean assertWarningValue(final String s, final String warningValue) {
final Matcher matcher = WARNING_HEADER_PATTERN.matcher(s);
final boolean matches = matcher.matches();
assert matches;
return matcher.group(1).equals(warningValue);
}
/**
* Logs a deprecated message to the deprecation log, as well as to the local {@link ThreadContext}.
*
* @param threadContexts The node's {@link ThreadContext} (outside of concurrent tests, this should only ever have one context).
* @param message The deprecation message.
* @param params The parameters used to fill in the message, if any exist.
*/
@SuppressLoggerChecks(reason = "safely delegates to logger")
void deprecated(final Set<ThreadContext> threadContexts, final String message, final Object... params) {
final Iterator<ThreadContext> iterator = threadContexts.iterator();
if (iterator.hasNext()) {
final String formattedMessage = LoggerMessageFormat.format(message, params);
final String warningHeaderValue = formatWarning(formattedMessage);
assert WARNING_HEADER_PATTERN.matcher(warningHeaderValue).matches();
assert extractWarningValueFromWarningHeader(warningHeaderValue).equals(escape(formattedMessage));
while (iterator.hasNext()) {
try {
final ThreadContext next = iterator.next();
next.addResponseHeader("Warning", warningHeaderValue, DeprecationLogger::extractWarningValueFromWarningHeader);
} catch (final IllegalStateException e) {
// ignored; it should be removed shortly
}
}
logger.warn(formattedMessage);
} else {
logger.warn(message, params);
}
}
/**
* Format a warning string in the proper warning format by prepending a warn code, warn agent, wrapping the warning string in quotes,
* and appending the RFC 7231 date.
*
* @param s the warning string to format
* @return a warning value formatted according to RFC 7234
*/
public static String formatWarning(final String s) {
return String.format(Locale.ROOT, WARNING_FORMAT, escape(s), RFC_7231_DATE_TIME.format(ZonedDateTime.now(GMT)));
}
/**
* Escape backslashes and quotes in the specified string.
*
* @param s the string to escape
* @return the escaped string
*/
public static String escape(String s) {
return s.replaceAll("([\"\\\\])", "\\\\$1");
}
}