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https://github.com/vy/log4j2-redis-appender
A Log4j 2 Appender for Redis.
https://github.com/vy/log4j2-redis-appender
java log4j2 logging redis
Last synced: 3 months ago
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A Log4j 2 Appender for Redis.
- Host: GitHub
- URL: https://github.com/vy/log4j2-redis-appender
- Owner: vy
- License: apache-2.0
- Created: 2017-05-17T11:58:59.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2024-04-29T00:31:54.000Z (9 months ago)
- Last Synced: 2024-05-02T06:09:20.360Z (9 months ago)
- Topics: java, log4j2, logging, redis
- Language: Java
- Size: 390 KB
- Stars: 32
- Watchers: 5
- Forks: 11
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Funding: .github/FUNDING.yml
- License: COPYING.txt
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README
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[](https://www.apache.org/licenses/LICENSE-2.0)
`RedisAppender` plugin provides a [Log4j 2.x](https://logging.apache.org/log4j/2.x/)
appender for [Redis](https://redis.io/) in-memory data structure store. The plugin
uses [Jedis](https://github.com/xetorthio/jedis) as a client for Redis.
# Usage
Add the `log4j2-redis-appender` dependency to your POM file
```xml
com.vlkan.log4j2
log4j2-redis-appender
${log4j2-redis-appender.version}
```
together with a valid `log4j-core` dependency:
```xml
org.apache.logging.log4j
log4j-core
${log4j2.version}
```
Below you can find a sample `log4j2.xml` snippet employing `RedisAppender`.
```xml
```
One can make `RedisAppender` work against a
[sentinel](https://redis.io/topics/sentinel) setup using `sentinelNodes` and
`sentinelMaster` parameters:
```xml
...
```
Note that `sentinelNodes` and `sentinelMaster` have priority over `host` and
`port` parameters.
`RedisAppender` is configured with the following parameters:
| Parameter Name | Type | Default | Description |
|----------------|------|---------|-------------|
| `charset` | String | `UTF-8` | output charset |
| `database` | int | 0 | Redis logical database |
| `key` | String | | Redis queue key |
| `host` | String | `localhost` | Redis host|
| `port` | int | 6379 | Redis port |
| `sentinelNodes` | String | `null` | Redis sentinel nodes as comma-separated list, e.g., `host1:port1,host2:port2`. If specified, `host` and `port` parameters are ignored. |
| `sentinelMaster` | String | `null` | Redis sentinel master name |
| `username` | String | `default` | Redis username |
| `password` | String | `null` | Redis password |
| `command` | String | `rpush` | Redis command for writing to the queue. Accepts `rpush` (default) and `publish`. |
| `connectionTimeoutSeconds` | int | 2 | initial connection timeout in seconds |
| `socketTimeoutSeconds` | int | 2 | socket timeout in seconds |
| `ignoreExceptions` | boolean | `true` | Enabling causes exceptions encountered while appending events to be internally logged and then ignored. When set to false, exceptions will be propagated to the caller, instead. You must set this to false when wrapping this appender in a `FailoverAppender`. |
| `Layout` | Layout | `PatternLayout` | used to format the `LogEvent`s |
| `RedisConnectionPoolConfig` | RedisConnectionPoolConfig | | Redis connection pool configuration |
| `RedisThrottlerConfig` | RedisThrottlerConfig | | Redis throttler configuration |
## Redis Connection Pool
`RedisConnectionPoolConfig` is a wrapper for `JedisPoolConfig` which extends
[GenericObjectPoolConfig](https://commons.apache.org/proper/commons-pool/apidocs/org/apache/commons/pool2/impl/GenericObjectPoolConfig.html)
of [Apache Commons Pool](https://commons.apache.org/proper/commons-pool/).
Below is a complete list of available `RedisConnectionPoolConfig` attributes.
| Parameter Name | Type | Default |
|----------------|------|-------------|
| `maxTotal` | int | 8 |
| `maxIdle` | int | 8 |
| `minIdle` | int | 0 |
| `lifo` | boolean | `true` |
| `fairness` | boolean | `false` |
| `maxWaitMillis` | long | -1 |
| `minEvictableIdleTimeMillis` | long | 1000 * 60 |
| `softMinEvictableIdleTimeMillis` | long | -1 |
| `numTestsPerEvictionRun` | int | -1 |
| `testOnCreate` | boolean | `false` |
| `testOnBorrow` | boolean | `false` |
| `testOnReturn` | boolean | `false` |
| `testWhileIdle` | boolean | `true` |
| `timeBetweenEvictionRunsMillis` | long | 1000 * 30 |
| `evictionPolicyClassName` | String | `org.apache.commons.pool2.impl.DefaultEvictionPolicy` |
| `blockWhenExhausted` | boolean | `true` |
| `jmxEnabled` | boolean | `true` |
| `jmxNameBase` | String | `null` |
| `jmxNamePrefix` | String | `com.vlkan.log4j2.redis.appender.JedisConnectionPool` |
## Redis Throttler
While Log4j 2 provides utilities like
[BurstFilter](https://logging.apache.org/log4j/2.x/manual/filters.html#BurstFilter)
and [AsyncAppender](https://logging.apache.org/log4j/2.x/manual/appenders.html#AsyncAppender)
that you can wrap around any appender to facilitate throttling,
[the appender API](https://logging.apache.org/log4j/2.0/log4j-core/apidocs/org/apache/logging/log4j/core/Appender.html)
[falls short of communicating this intent](http://mail-archives.apache.org/mod_mbox/logging-dev/201706.mbox/browser).
Hence, `RedisAppender` provides its own throttling mechanics to exploit batch
pushes available in [Redis RPUSH](https://redis.io/commands/rpush). This
feature is configured by `RedisThrottlerConfig` element using the following
attributes:
| Parameter Name | Type | Description |
|----------------|------|-------------|
| `bufferSize` | int | `LogEvent` buffer size (defaults to 500) |
| `batchSize` | int | size of batches fed into Redis `RPUSH` (defaults to 100) |
| `flushPeriodMillis` | long | buffer flush period (defaults to 1000) |
| `maxEventCountPerSecond` | double | allowed maximum number of events per second (defaults to 0, that is, unlimited) |
| `maxByteCountPerSecond` | double | allowed maximum number of bytes per second (defaults to 0, that is, unlimited) |
| `maxErrorCountPerSecond` | double | allowed maximum number of errors per second propagated (defaults to 0.003, that is, approximately once every 5 minutes) |
| `jmxBeanName` | String | `RedisThrottlerJmxBean` name (defaults to `org.apache.logging.log4j2:type=,component=Appenders,name=,subtype=RedisThrottler`) |
The buffer is flushed if either there are more than `batchSize` events
queued in the buffer, or the last flush was older than `flushPeriodMillis`.
`maxErrorCountPerSecond` is there to avoid flooding logs if the application
is suffering a shortage of memory, or the Redis server is unreachable.
Fat JAR
=======
Project also contains a `log4j2-redis-appender-fatjar` artifact which
includes all its transitive dependencies in a separate shaded package (to
avoid the JAR Hell) with the exception of `log4j-core`, that you need to
include separately.
This might come handy if you want to use this plugin along with already
compiled applications, e.g., Elasticsearch 5.x, which requires Log4j 2.x.
F.A.Q.
======
- **How can I connect to multiple Redis servers for failover?** You can define
multiple Redis appenders nested under a
[FailoverAppender](https://logging.apache.org/log4j/2.x/manual/appenders.html#FailoverAppender).
(Don't forget to turn off `ignoreExceptions` flag.)
- **How can I avoid getting `AccessControlException` exceptions?** If you are
using the plugin in a security manager enabled Java application (for
instance, which is the case for Elasticsearch since version 2.3), you
might be getting `AccessControlException` exceptions as follows:
```
[2017-06-23T11:25:35,644][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [tst-store-001.data] uncaught exception in thread [commons-pool-EvictionTimer]
java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "setContextClassLoader")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:472) ~[?:1.8.0_131]
at java.security.AccessController.checkPermission(AccessController.java:884) ~[?:1.8.0_131]
at java.lang.SecurityManager.checkPermission(SecurityManager.java:549) ~[?:1.8.0_131]
at java.lang.Thread.setContextClassLoader(Thread.java:1474) [?:1.8.0_131]
at org.apache.commons.pool2.impl.BaseGenericObjectPool$Evictor.run(BaseGenericObjectPool.java:1052) ~[log4j2-redis-appender.jar:?]
at java.util.TimerThread.mainLoop(Timer.java:555) ~[?:1.8.0_131]
at java.util.TimerThread.run(Timer.java:505) ~[?:1.8.0_131]
```
To alleviate this, you need to grant necessary permissions using a
[policy file](http://docs.oracle.com/javase/8/docs/technotes/guides/security/PolicyFiles.html):
```
grant {
permission java.lang.RuntimePermission "setContextClassLoader";
};
```
Then you can activate this policy for your application via either placing it
under one of [default policy file locations](http://docs.oracle.com/javase/8/docs/technotes/guides/security/PolicyFiles.html#DefaultLocs)
(e.g., `$JAVA_HOME/lib/security/java.policy`) or providing it as an argument
at runtime, that is, `-Djava.security.policy=someURL`.
- **How can I access JMX bean of an appender?** Once you have a reference to
the relevant `LoggerContext`, you can access the instance of the appender
and its JMX bean by its name as follows:
```java
Appender appender = loggerContext.getConfiguration().getAppender("REDIS");
RedisThrottlerJmxBean jmxBean = ((RedisAppender) appender).getJmxBean();
```
You can either create your own `LoggerContext`:
```java
LoggerContextResource loggerContextResource = new LoggerContextResource("/path/to/log4j2.xml");
LoggerContext loggerContext = loggerContextResource.getLoggerContext();
```
or get a handle to an existing one:
```java
LoggerContext logContext = (LoggerContext) LogManager.getContext(false);
```
Here note that you should be using `org.apache.logging.log4j.core.LoggerContext`,
not `org.apache.logging.log4j.spi.LoggerContext`.
Contributors
============
- [Boris Faniuk](https://github.com//bfanyuk)
- [Khaled Bakhtiari](https://github.com/ec84b4)
- [Roberto Martinez Caballero](https://github.com/rmarticaba)
- [t9t](https://github.com/t9t)
- [Yaroslav Skopets](https://github.com/yskopets)
# Security policy
If you have encountered an unlisted security vulnerability or other unexpected behaviour that has security impact, please report them privately to the [[email protected]](mailto:[email protected]) email address.
# License
Copyright © 2017-2024 [Volkan Yazıcı](https://volkan.yazi.ci/)
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
https://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.