GraphGen4Code

Knowledge graphs have been proven extremely useful in powering diverse applications in semantic search and natural language understanding. In this work, we present GraphGen4Code, a toolkit to build code knowledge graphs that can similarly power various applications such as program search, code understanding, bug detection, and code automation. GraphGen4Code uses generic techniques to capture code semantics with the key nodes in the graph representing classes, functions and methods. Edges indicate function usage (e.g., how data flows through function calls, as derived from program analysis of real code), and documentation about functions (e.g., code documentation, usage documentation, or forum discussions such as StackOverflow). Our toolkit uses named graphs in RDF to model graphs per program, or can output graphs as JSON. We show the scalability of the toolkit by applying it to 1.3 million Python files drawn from GitHub, 2,300 Python modules, and 47 million forum posts. This results in an integrated code graph with over 2 billion triples. We make the toolkit to build such graphs as well as the sample extraction of the 2 billion triples graph publicly available to the community for use.

How is GraphGen4Code different from other frameworks?

Static analysis in GraphGen4Code is different from other analysis libraries in the following aspects:

Does not assume each program is self contained, but in fact uses other libraries. Calls to each library function is explicitly modeled in the analysis (and data flow is approximated through the call).
Follows data and control flow across multiple function calls within the same script.
Simulates each function call within the script, even if the script does not explicitly call the functions (i.e., there is no main). This sort of analysis is needed to handle real Python code - most are full of library calls, most have different functions through which data flow and control flow occurs. Many of the real world applications we look at that have been built on top of GraphGen4Code require for instance starting points for analysis that are library calls (e.g., start with pandas.read_csv), and proceeds till some end condition is needed (e.g., end with a fit call on any of the estimators in a data science pipeline).

Indeed, this is a better approximation of program graphs than what is currently produced by frameworks such as python_graphs. python_graphs as an example assumes:

Every function call occurs within the scope of the program. No library calls appear in the program graph.
The analysis is strictly NOT interprocedural.
Only calls within a script to a function are modeled.

Website: https://wala.github.io/graph4code/

Applications

Create your own graph

GraphGen4Code Pipeline<a name="pipeline"></a>

The figure below shows the overall pipeline of steps followed by GraphGen4Code to generate large-scale code knowledge graphs.

<p align="center"> <img align="center" src="./docs/figures//graph4code_pipeline.png" width="90%"/> </p> <br><br>

We used the above pipeline to demonstrate the scalability of GraphGen4Code by creating a code knowledge graph of 2 billion facts about code. This graph was created using 1.3 million Python program and 47 million forum posts. The graph files are available here. To load and query this data, please follow the instructions here: https://github.com/wala/graph4code/blob/master/docs/load_graph.md. We also provide scripts for creating a docker image with the graph database ready to use.

We list below the steps needed to create your own graph.

Requirements

For this, create a conda environment with conda create --name g4c python=3.9.

pip install bs4 rdflib validators torch xmltodict numpy

pip install elasticsearch
Install ElasticSearch (tested with 8.2.1).

wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-8.2.1-linux-x86_64.tar.gz

tar -xzf elasticsearch-8.2.1-linux-x86_64.tar.gz

export ES_HOME=/data/graph4code/elasticsearch-8.2.1/config/certs/

cd elasticsearch-8.2.1/

./bin/elasticsearch

Elastic search now starts with a bunch of security features enabled. Make sure to find the elastic search user password in its display when you start: Password for the elastic user (reset with bin/elasticsearch-reset-password -u elastic):<password>. Export the password as an environment variable.
export ES_PASSWORD=<password>

You will also need an installation of Java JDK 11 for running the jars of code analysis (next step).

Code Analysis Graph

If you have a new script (code file), run the following command in the jars directory. Please ensure you have Java 11 before you run. Note that the last two arguments are to create a unique graph URI for each script that gets analyzed, where the graph URI is made up of <graph prefix> + '/' + <graph qualifier> for a single file. Note also that we have migrated the RDF store model to RDF* to make it a more compact, easier to understand representation. We have also added more information about each node. Model definition will be updated soon.

We provide analysis for both Python 2 and Python 3. Python 3 is the supported version of Python, but, while Python 2 is no longer supported, many existing datasets have significant quantities it. Since the two languages have different syntax in some cases, we need two different analyses that rely on diffferent parsers, and hence we have two analysis jars. ** All source code for the files that perform operations on the analysis graphs is now included - see directories that start with the string codebreaker. **

Build the code analysis libraries

Fetch these jars from https://archive.org/download/graph4code_prereq_jars/graph4code_prereq_jars.tar. In graph4code, untar.

 cd scripts
 bash setup.sh

Usage:

 java -DoutputDir=<output dir to store JSON representation of graph> -DquadFile=<file name to write quads to - this file gets appended to, so all analyzed scripts end up in a single file> -cp <absolute path of codebreaker*n*.jar> util.RunTurtleSingleAnalysis <python script to run on> <graph prefix> <graph qualifier>

where n is either 2 or 3 depending on the desired version of Python.

Example

 java -DoutputDir=<output dir to store JSON representation of graph> -cp ../code_breaker_py3/target/CodeBreaker_py3-0.0.1-SNAPSHOT.jar util.RunTurtleSingleAnalysis <python script to run on> null null` to run on a Python 3 file, with an output of the graph on JSON.

So to run on an example script provided from the main directory, use

    mkdir -p ./output/static_analysis/ 
    java -DoutputDir=./output/static_analysis/ -cp ../code_breaker_py3/target/CodeBreaker_py3-0.0.1-SNAPSHOT.jar  util.RunTurtleSingleAnalysis ./example_scripts/test1.py null null

./output/static_analysis should have a JSON file and an NQ file for the same information. Please note that as the project has moved on to different applications, we have focused more on the JSON representation which is up to date. The NQ is less what we use and test - so it may be out of date.

Collecting documentation (docstrings) for your scripts

Run python generate_top_modules.py <DIR containing all analysis output>/*.json <OUTPUT_TOP_MODULES_PATH> <number for top K modules by count>.

Example: to run on the example script provided, run in the src dir:
```
 python generate_top_modules.py '../output/static_analysis/*.json.bz2' ../output/top_modules.json 1
```
From the scripts dir, run:

sh inspect_modules_for_docstrings.sh <OUTPUT_TOP_MODULES_PATH> <OUTPUT_TO_WRITE_EXTRACTED_DOCSTRINGS> <ANACONDA_HOME>

Example:

    mkdir ../output/modules_out/    
    sh inspect_modules_for_docstrings.sh ../output/top_modules.json ../output/modules_out/ ~/anaconda3/

You should see each package being inspected, and some output that looks like this: Number of documents stored in index:docstrings_index {'count': <xxx>, '_shards': {'total': 1, 'successful': 1, 'skipped': 0, 'failed': 0}}

Remember to delete the index if you are recreating it for the same packages.

Creating docstrings graph

Using the output of the above step, run the following from inside the src directory

 python create_docstrings_graph.py --docstring_dir <directory where docstrings from above directory are saved> --class_map_file ../resources/classes.map --out_dir <where nq files will be saved

Example:

     mkdir ../output/docstrings_graph/    
     python create_docstrings_graph.py --docstring_dir ../output/modules_out/ --class_map_file ../resources/classes.map --out_dir ../output/docstrings_graph/

Creating Forums graph

Additional requirements:

pip install xmltodict
pip install rdflib
pip install validators
Install pytorch using instructions for your OS. E.g.: conda install pytorch torchvision torchaudio cpuonly -c pytorch.

To create a forum graph, first download the corresponding data dump from StackOverflow or StackExchange from https://archive.org/details/stackexchange. You then need to extract the zipped fil

Graph4code

Install / Use

README