[TINKERPOP-1278] Implement Gremlin-Python and general purpose language variant test infrastructure - ASF JIRA

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Details

Type: Improvement
Status: Closed
Priority: Major
Resolution: Fixed
Affects Version/s: 3.2.0-incubating
Fix Version/s: 3.2.2
Component/s: python
Labels:
None

Description

As discussed on dev@...

Apache TinkerPop should provide, out-of-the-box, at least 3 Gremlin language variants. It would be cool if these were:

Python (Mark Henderson)
PHP (PommeVerte)
Ruby (?okram)

I think each of these should be generated using the reflection-model presented in http://tinkerpop.apache.org/docs/3.2.1-SNAPSHOT/tutorials/gremlin-language-variants/. Moreover, on every mvn clean install, the code for these variants is generated.

Given the desire to separate language variants from language drivers, I think that a language driver for each variant above should be "plugable." Moreover, we should provide one driver implementation for each – simple GremlinServer REST.

gremlin-variants/
  gremlin-ruby/
    gremlin_ruby.rb
    gremlin_ruby_rest_driver.rb
  gremlin-php/
    Gremlin_PHP.php
    Gremlin_PHP_REST_Driver.php
  gremlin-python/
    gremlin-python.py
    gremlin-python-rest-driver.py

Next, each variant implementation should be testable. This is PAINFUL if we have to implement each g_V_out_repeatXasXaXX test case in ProcessXXXSuite. Perhaps some RegEx transducer magic could be used to convert all those tests from Gremlin-Java to the respective host language? However, even if we do that, we still have the problem of how to test the returned results.

I think what we should test the returned results using the JVM. For instance, JRuby, Jython, JPHP (does it exist?). If we do this, we will save ourselves a massive headache. All we have to do is create a GraphProvider that uses TinkerGraph and whose TraversalSource is some sort of wrapper around reflection-generated Ruby (e.g.).

g.V.out_e("knows") // returns a Ruby iterator

That Ruby iterator should be converted to a Java iterator and then the ProcessXXXSuite can verify the results.

With this, most everything is reflectively constructed.

gremlin_ruby.rb             // generated via Java reflection
gremlin_ruby_rest_driver.rb // manually coded
match_test.rb               // generated via RegEx transducer
has_test.rb                 // generated via RegEx transducer
...
RubyGraphProvider.java        // manually coded
RubyProcessStandardSuite.java // manually coded
RubyProcessComputerSuite.java // manually coded

Thus, the testing data flow would be:

MatchTest.Traversals.java --transducer-> match_test.rb
match-test.rb --REST--> GremlinServer
GremlinServer --GraphSON-->match-test.rb
GraphSON --JRuby/GraphSONReader-->Java objects
Java objects --JRuby-->MatchTest.java