### What is this PR for?
This PR is applying new interpreter register mechanism to python interpreter.
### What type of PR is it?
Improvement
### What is the Jira issue?
[ZEPPELIN-1045](https://issues.apache.org/jira/browse/ZEPPELIN-1045)
### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No
Author: Mina Lee <minalee@apache.org>
Closes#1063 from minahlee/ZEPPELIN-1045 and squashes the following commits:
66b8f73 [Mina Lee] Add zeppelin.python.maxResult property to python interpreter
5013890 [Mina Lee] Apply new mechanism to PythonInterpreter
### What is this PR for?
This is first step improving current Python interpreter implementation.
It has just a cleanup, style and docs improvements.
### What type of PR is it?
Improvement
### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No
Author: Alexander Bezzubov <bzz@apache.org>
Closes#1021 from bzz/improve/python and squashes the following commits:
3cafa22 [Alexander Bezzubov] Python: make interpreter logs less verbose
744f7d2 [Alexander Bezzubov] Python: move technical details from doc to README.md
0f74e5d [Alexander Bezzubov] Python: return first running job
08c2bb4 [Alexander Bezzubov] Python: upd Java code to conform project conventions
e84cd5c [Alexander Bezzubov] Python: normalize newlines in python
58efcc9 [Alexander Bezzubov] Python: normalize newlines in Java
### What is this PR for?
Adding a python 2 &3 interpreter. It's a basic implementation (no py4j for example), with a java ProcessBuilder object used to instantiate a python REPL.
The interpreter doesn't bring it own python binary but uses the python specified by python.path configutation. Thus, you can still use your specific installed python modules (scikit-learn, matplotlib...) and the interpreter is able to work with python 2 & 3 without change.
I had a python helper function (zeppelin_show() ) to easily display matplotlib graph as SVG.
### What type of PR is it?
[Feature]
### Todos
* [x] - Code review
* [x] - Improve bootstrap.py : choose available helper functions and their names
* [x] - Unit / IT tests ?
* [x] documentation updates needed, that AhyoungRyu pointed out
* [X] LICENSE needs to be updated to include all non-apache licensed dependencies (i.e AFAIK Py4j is BSD ) in bin-license
* [x] double-check that code formatting conforms project style guide
* [x] the branch need to be rebased on latest master.
### What is the Jira issue?
[ZEPPELIN-502](https://issues.apache.org/jira/browse/ZEPPELIN-502?jql=project%20%3D%20ZEPPELIN%20AND%20text%20~%20%22python%22)
### How should this be tested?
1. In interpreter screen, in Python section, specify in python.path the python binary you want to use
2. In a paragraph, you can use the interpreter with **_%python_**. Calling help() will describe you the interpreter functionnalities.
3. Install py4j (pip install py4j) if you want to use input form
### Screenshots
### Questions:
* Does the licenses files need update? Yes, only bin-license (py4j)
* Is there breaking changes for older versions? No
* Does this needs documentation? Yes
Author: Hervé RIVIERE <hriviere@users.noreply.github.com>
Closes#869 from hriviere/PR_interpreter_python and squashes the following commits:
80b6e75 [Hervé RIVIERE] [ZEPPELIN-502] move BSD py4j license to zeppelin-distribution/src/bin_license/license
a4b82a5 [Hervé RIVIERE] [ZEPPELIN-502]Improving doc following @AhyoungRyu review
3252353 [Hervé RIVIERE] [ZEPPELIN-502] Formatting code to respect project convention
54ec4f1 [Hervé RIVIERE] [ZEPPELIN-502]Improving doc following @AhyoungRyu review
6a831bc [Hervé RIVIERE] [ZEPPELIN-502] Add BSD py4j license
11e1b9c [Hervé RIVIERE] [ZEPPELIN-502] minor changes in python.md
e5d0bdb [Hervé RIVIERE] [ZEPPELIN-502] change PYTHON_PATH to ZEPPELIN_PYTHON
c62ac98 [Hervé RIVIERE] [ZEPPELIN-502] Improve python.md
5008125 [Hervé RIVIERE] [ZEPPELIN-502] Improve python.md with features not yet supported and technical description
7d533e1 [Hervé RIVIERE] [ZEPPELIN-502] Add tests and reformating code to help tests writing
fecaf25 [Hervé RIVIERE] [ZEPPELIN-502] Rename python.path to python and default from /usr/bin/python to python
02d1320 [Hervé RIVIERE] [ZEPPELIN-502] Input form, change from simple input form to native (pyspark syntax)
60d2956 [Hervé RIVIERE] [ZEPPELIN-502] Indent as pep8 convention
9bdb192 [Hervé RIVIERE] [ZEPPELIN-502] Add python.md to _navigation.html
7142aa5 [Hervé RIVIERE] [ZEPPELIN-502] Catch exception in logger.error
1a86ad7 [Hervé RIVIERE] [ZEPPELIN-502] Python interpreter group
