## What is the purpose of the change
The purpose is to print the final java command when running `bin/flink`, this
would be useful for developer to debug the flink program especially when
hitting weird launch issue such classpath issue.
## Brief change log
Just introduce env variable `PRINT_FLINK_COMMAND`, when it is set, user can see
the final java command.
## Verifying this change
User can print flink command via setting env PRINT_FLINK_COMMAND.
e.g.
```
export PRINT_FLINK_COMMAND=1
bin/flink run -h
```
Here's the output
```
FLINK_COMMAND:/Library/Java/JavaVirtualMachines/jdk1.8.0_172.jdk/Contents/Home/bin/java
-Dlog.file=/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/log/flink-jzhang-client-HW12527.log
-Dlog4j.configuration=file:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/conf/log4j-cli.properties
-Dlogback.configurationFile=file:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/conf/logback.xml
-classpath
:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/lib/flink-dist_2.11-1.7-SNAPSHOT.jar:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/lib/flink-python_2.11-1.7-SNAPSHOT.jar:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/lib/flink-shaded-hadoop2-uber-1.7-SNAPSHOT.jar:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/lib/log4j-1.2.1
7.jar:/Users/jzhang/github/flink/flink-dist/target/flink-1.7-SNAPSHOT-bin/flink-1.7-SNAPSHOT/lib/slf4j-log4j12-1.7.7.jar:::
org.apache.flink.client.cli.CliFrontend run -h
Action "run" compiles and runs a program.
Syntax: run [OPTIONS] <jar-file> <arguments>
"run" action options:
-c,--class <classname> Class with the program entry point
("main" method or "getPlan()" method.
Only needed if the JAR file does not
specify the class in its manifest.
...
```
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): (no)
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: (no)
- The serializers: (no)
- The runtime per-record code paths (performance sensitive): (no)
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
- The S3 file system connector: (no)
## Documentation
- Does this pull request introduce a new feature? (no)
- If yes, how is the feature documented? (not documented)
[ Full content available at: https://github.com/apache/flink/pull/6690 ]
This message was relayed via gitbox.apache.org for [email protected]
