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From "Alex Birch (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (LOG4J2-1369) "xz" compression results in plaintext, uncompressed files.
Date Mon, 18 Apr 2016 16:06:25 GMT

     [ https://issues.apache.org/jira/browse/LOG4J2-1369?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Alex Birch updated LOG4J2-1369:
-------------------------------
    Description: 
_Note: see [associated StackOverflow problem](https://stackoverflow.com/questions/36695617/enabling-lzma2-i-e-xz-compression-in-log4j2)_

== Current state of world

Currently our `RollingFileAppender` in `log4j2.xml` uses Gzip compression:

```
<RollingFile name="RollingFile"
             fileName="logs/engine.log"
             filePattern="logs/engine.log.%i.gz">
```

# Goal

I would like to switch to LZMA(2) (i.e. `.xz`) compression, to enjoy an improved compression
ratio.

# Attempt

I have tried changing `engine.log.%i.gz` to `engine.log.%i.xz` — as per [the documentation](https://logging.apache.org/log4j/2.x/manual/appenders.html#DefaultRolloverStrategy):

> If the file pattern ends with `.gz`, `.zip`, `.bz2`, `.deflate`, `.pack200`, or `.xz`
the resulting archive will be compressed using the compression scheme that matches the suffix.
The formats bzip2, Deflate, Pack200 and XZ require Apache Commons Compress. In addition, XZ
requires [XZ for Java](http://tukaani.org/xz/java.html).

Additionally I have ensured that I have a runtime dependency on [XZ for Java](http://tukaani.org/xz/java.html)
— via `pom.xml`:

```
<dependency>
    <!-- Support Log4j2 Log compression schemes: ".gz", ".zip", ".bz2", ".deflate", ".pack200",
[".xz" (part 1 of 2)] -->
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.11</version>
</dependency>
<dependency>
    <!-- Support Log4j2 Log compression scheme [".xz" (part 2 of 2)] -->
    <groupId>org.tukaani</groupId>
    <artifactId>xz</artifactId>
    <version>1.5</version>
</dependency>
```

# Result

When the RollingFileAppender is triggered: the archive created is indeed _named_ `engines.log.1.xz`
— as required.

**However**, its contents are incorrect:

**Expectation**

`engines.log.1.xz` should contain LZMA(2) compressed text

**Actual**

`engines.log.1.xz` instead contains plain, uncompressed text.

# Sanity checks

I confirm that the `org.tukaani:xz` and `org.apache.commons:commons-compress` successfully
made it into the classpath of my jar:

```
🍔 jar tf mycooljar.jar | grep tukaani
org/tukaani/
org/tukaani/xz/
...

🍔 jar tf mycooljar.jar | grep org/apache/commons/compress
org/apache/commons/compress/
org/apache/commons/compress/changes/
...
```

This Java program is not deployed to a J2EE webserver. I believe its class loading is straightforward.

# Summary

I have correctly followed the instructions necessary to create `.gz` archives.

I believe the only additional step required to create `.xz` archives is: I must provide at
runtime the [XZ for Java](http://tukaani.org/xz/java.html) artefact. I have done this.

Am I missing something here? I am tempted to believe one of the following:

 - The functionality is broken
 - The docs are incomplete/incorrect
 - log4j2 fails to discover the class at runtime

# Leads so far

I was able to find some evidence that perhaps I am expected to input `.xy` instead of `.xz`.
If I use `.xy`: the log4j2 `RollingAppender` fails to produce archives. That is: it creates
blank `.xy` files, and retains the unarchived plaintext as a `.log` file. It smells like a
buggy implementation.

Here is the code I present as evidence from `org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy`:
```
static enum FileExtensions {
    XY(".xy") {
        @Override
        Action createCompressAction(final String renameTo, final String compressedName, final
boolean deleteSource,
                 final int compressionLevel) {
             // One of "gz", "bzip2", "xz", "pack200", or "deflate".
             return new CommonsCompressAction("xy", source(renameTo), target(compressedName),
deleteSource);
        }
    }
}
```

  was:
_Note: see [associated StackOverflow problem](https://stackoverflow.com/questions/36695617/enabling-lzma2-i-e-xz-compression-in-log4j2)_

= Current state of world

Currently our `RollingFileAppender` in `log4j2.xml` uses Gzip compression:

```
<RollingFile name="RollingFile"
             fileName="logs/engine.log"
             filePattern="logs/engine.log.%i.gz">
```

# Goal

I would like to switch to LZMA(2) (i.e. `.xz`) compression, to enjoy an improved compression
ratio.

# Attempt

I have tried changing `engine.log.%i.gz` to `engine.log.%i.xz` — as per [the documentation](https://logging.apache.org/log4j/2.x/manual/appenders.html#DefaultRolloverStrategy):

> If the file pattern ends with `.gz`, `.zip`, `.bz2`, `.deflate`, `.pack200`, or `.xz`
the resulting archive will be compressed using the compression scheme that matches the suffix.
The formats bzip2, Deflate, Pack200 and XZ require Apache Commons Compress. In addition, XZ
requires [XZ for Java](http://tukaani.org/xz/java.html).

Additionally I have ensured that I have a runtime dependency on [XZ for Java](http://tukaani.org/xz/java.html)
— via `pom.xml`:

```
<dependency>
    <!-- Support Log4j2 Log compression schemes: ".gz", ".zip", ".bz2", ".deflate", ".pack200",
[".xz" (part 1 of 2)] -->
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-compress</artifactId>
    <version>1.11</version>
</dependency>
<dependency>
    <!-- Support Log4j2 Log compression scheme [".xz" (part 2 of 2)] -->
    <groupId>org.tukaani</groupId>
    <artifactId>xz</artifactId>
    <version>1.5</version>
</dependency>
```

# Result

When the RollingFileAppender is triggered: the archive created is indeed _named_ `engines.log.1.xz`
— as required.

**However**, its contents are incorrect:

**Expectation**

`engines.log.1.xz` should contain LZMA(2) compressed text

**Actual**

`engines.log.1.xz` instead contains plain, uncompressed text.

# Sanity checks

I confirm that the `org.tukaani:xz` and `org.apache.commons:commons-compress` successfully
made it into the classpath of my jar:

```
🍔 jar tf mycooljar.jar | grep tukaani
org/tukaani/
org/tukaani/xz/
...

🍔 jar tf mycooljar.jar | grep org/apache/commons/compress
org/apache/commons/compress/
org/apache/commons/compress/changes/
...
```

This Java program is not deployed to a J2EE webserver. I believe its class loading is straightforward.

# Summary

I have correctly followed the instructions necessary to create `.gz` archives.

I believe the only additional step required to create `.xz` archives is: I must provide at
runtime the [XZ for Java](http://tukaani.org/xz/java.html) artefact. I have done this.

Am I missing something here? I am tempted to believe one of the following:

 - The functionality is broken
 - The docs are incomplete/incorrect
 - log4j2 fails to discover the class at runtime

# Leads so far

I was able to find some evidence that perhaps I am expected to input `.xy` instead of `.xz`.
If I use `.xy`: the log4j2 `RollingAppender` fails to produce archives. That is: it creates
blank `.xy` files, and retains the unarchived plaintext as a `.log` file. It smells like a
buggy implementation.

Here is the code I present as evidence from `org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy`:
```
static enum FileExtensions {
    XY(".xy") {
        @Override
        Action createCompressAction(final String renameTo, final String compressedName, final
boolean deleteSource,
                 final int compressionLevel) {
             // One of "gz", "bzip2", "xz", "pack200", or "deflate".
             return new CommonsCompressAction("xy", source(renameTo), target(compressedName),
deleteSource);
        }
    }
}
```


> "xz" compression results in plaintext, uncompressed files.
> ----------------------------------------------------------
>
>                 Key: LOG4J2-1369
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-1369
>             Project: Log4j 2
>          Issue Type: Bug
>          Components: Appenders, Core, Documentation
>    Affects Versions: 2.5
>         Environment: Java SE 1.7
>            Reporter: Alex Birch
>
> _Note: see [associated StackOverflow problem](https://stackoverflow.com/questions/36695617/enabling-lzma2-i-e-xz-compression-in-log4j2)_
> == Current state of world
> Currently our `RollingFileAppender` in `log4j2.xml` uses Gzip compression:
> ```
> <RollingFile name="RollingFile"
>              fileName="logs/engine.log"
>              filePattern="logs/engine.log.%i.gz">
> ```
> # Goal
> I would like to switch to LZMA(2) (i.e. `.xz`) compression, to enjoy an improved compression
ratio.
> # Attempt
> I have tried changing `engine.log.%i.gz` to `engine.log.%i.xz` — as per [the documentation](https://logging.apache.org/log4j/2.x/manual/appenders.html#DefaultRolloverStrategy):
> > If the file pattern ends with `.gz`, `.zip`, `.bz2`, `.deflate`, `.pack200`, or
`.xz` the resulting archive will be compressed using the compression scheme that matches the
suffix. The formats bzip2, Deflate, Pack200 and XZ require Apache Commons Compress. In addition,
XZ requires [XZ for Java](http://tukaani.org/xz/java.html).
> Additionally I have ensured that I have a runtime dependency on [XZ for Java](http://tukaani.org/xz/java.html)
— via `pom.xml`:
> ```
> <dependency>
>     <!-- Support Log4j2 Log compression schemes: ".gz", ".zip", ".bz2", ".deflate",
".pack200", [".xz" (part 1 of 2)] -->
>     <groupId>org.apache.commons</groupId>
>     <artifactId>commons-compress</artifactId>
>     <version>1.11</version>
> </dependency>
> <dependency>
>     <!-- Support Log4j2 Log compression scheme [".xz" (part 2 of 2)] -->
>     <groupId>org.tukaani</groupId>
>     <artifactId>xz</artifactId>
>     <version>1.5</version>
> </dependency>
> ```
> # Result
> When the RollingFileAppender is triggered: the archive created is indeed _named_ `engines.log.1.xz`
— as required.
> **However**, its contents are incorrect:
> **Expectation**
> `engines.log.1.xz` should contain LZMA(2) compressed text
> **Actual**
> `engines.log.1.xz` instead contains plain, uncompressed text.
> # Sanity checks
> I confirm that the `org.tukaani:xz` and `org.apache.commons:commons-compress` successfully
made it into the classpath of my jar:
> ```
> 🍔 jar tf mycooljar.jar | grep tukaani
> org/tukaani/
> org/tukaani/xz/
> ...
> 🍔 jar tf mycooljar.jar | grep org/apache/commons/compress
> org/apache/commons/compress/
> org/apache/commons/compress/changes/
> ...
> ```
> This Java program is not deployed to a J2EE webserver. I believe its class loading is
straightforward.
> # Summary
> I have correctly followed the instructions necessary to create `.gz` archives.
> I believe the only additional step required to create `.xz` archives is: I must provide
at runtime the [XZ for Java](http://tukaani.org/xz/java.html) artefact. I have done this.
> Am I missing something here? I am tempted to believe one of the following:
>  - The functionality is broken
>  - The docs are incomplete/incorrect
>  - log4j2 fails to discover the class at runtime
> # Leads so far
> I was able to find some evidence that perhaps I am expected to input `.xy` instead of
`.xz`. If I use `.xy`: the log4j2 `RollingAppender` fails to produce archives. That is: it
creates blank `.xy` files, and retains the unarchived plaintext as a `.log` file. It smells
like a buggy implementation.
> Here is the code I present as evidence from `org.apache.logging.log4j.core.appender.rolling.DefaultRolloverStrategy`:
> ```
> static enum FileExtensions {
>     XY(".xy") {
>         @Override
>         Action createCompressAction(final String renameTo, final String compressedName,
final boolean deleteSource,
>                  final int compressionLevel) {
>              // One of "gz", "bzip2", "xz", "pack200", or "deflate".
>              return new CommonsCompressAction("xy", source(renameTo), target(compressedName),
deleteSource);
>         }
>     }
> }
> ```



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