CAmpPython

This is the C code generator for the DTN Management Architecture (DTNMA). It is part of the larger Asynchronous Network Managment System (ANMS) managed for NASA AMMOS.

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This tool uses the YANG representation of an Application Data Model (ADM) to generate code for various purposes. CAmp generates:

• C code for usage in a C-implemented DTNMA agent
  • This generation can also carry over custom functions in existing C files for the ADM, if indicated appropriately in the existing code (see the Round-tripping Section).
• SQL code for usage by the ANMS manager
• ACE input files, for usage with the ARI CBOR Encoder (ACE) Tool

Please contact the developers for more information or suggestions. The Architecture Section also provides some explanation of the components of CAmp, and how to incorporate additional generators.

NOTE CAmp largely assumes that the ADM YANG input can be trusted (i.e., CAmp does not go to great lengths to fully sanitize all strings found within the ADM). CAmp does properly escape necessary sequences found in the ADMs tested during development (e.g., apostrophes in object descriptions).

Development

To install development and test dependencies for this project, run from the root directory (possibly under sudo if installing to the system path):

pip3 install -r <(python3 -m piptools compile --extra test pyproject.toml 2>&1)

To install the project itself from source run:

pip3 install .

View Usage Options for CAmp

    camp -h

Basic Usage

The camp tool takes a YANG representation of an ADM for a network protocol as input and calls each of the included generators to generate files for the ADM.

For information on how to format a YANG ADM, please consult the Application Management Model IETF draft.

Given the YANG representation of the ADM, run camp with:

   camp <adm.yang>

Name Registry

If you're generating files for a new ADM, you may see an error similar to the following:

[Error] this ADM is not present in the name registry. Pass integer value via
command line or set manually in name_registry.cfg

This is because the name of the ADM is not yet present in the camp Name Registry. To solve this, pass the nickname value for the ADM to camp via the -n command line option:

    camp <adm.json> -n <value>

You can also use the -n option to make camp use a different nickname for an ADM that is present in the camp Name Registry. For example,

    camp bp_agent.json -n 23

Will generate bp_agent files with a nickname of 23 instead of the registered value of 2. To make these changes permanent (or to add a new ADM to the name registry), pass the -u flag to camp:

    camp <adm.json> -n <value> -u

Output

During a successful camp execution, output similar to the following will be printed to STDOUT.

Loading  <path_to_json_file>/<adm.json>  ... 
[ DONE ]
Generating files ...
Working on  .//ace/adm_<adm>.json   [ DONE ]
Working on  .//agent/adm_<adm>_impl.h   [ DONE ]
Working on  .//agent/adm_<adm>_impl.c   [ DONE ]
Working on  .//adm_<adm>.sql        [ DONE ]
Working on  .//shared/adm_<adm>.h   [ DONE ]
Working on  .//mgr/adm_<adm>_mgr.c  [ DONE ]
Working on  .//agent/adm_<adm>_agent.c  [ DONE ]
[ End of CAmpPython Execution ]

This output shows that camp completed a successful generation of each of the files listed. If they don't already exist, camp will create the following directories in the current directory:

• ace
• agent
• shared
• mgr

and put generated files into the appropriate created directory. Use the -o flag with camp to redirect output to a different directory.

    camp <adm.json> -o <output_directory>

If the path at does not already exist, camp will create it, and will create the directories listed above within .

Camp will not delete any existing directory structure, but files present in the output directories with the same name as generated files will be overwritten.

Custom Code and Round-tripping

The adm_<adm>_impl.c and adm_<adm>_impl.h files generated for the DTNMA agent contain functions whose bodies cannot be automatically generated with knowledge of the ADM alone. When generated, these fuctions are marked with tags similar to the following:

    /*
     * +----------------------------------------------------------------------+
     * |START CUSTOM FUNCTION <function_name> BODY
     * +----------------------------------------------------------------------+
     */ 
    /*
     * +----------------------------------------------------------------------+
     * |STOP CUSTOM FUNCTION <function_name> BODY   
     * +----------------------------------------------------------------------+
     */ 

Additionally, the user may wish to add additional custom functions and/or header files to these generated files. To allow re-generation of camp files with minimal re-work for custom code in these files, camp has a 'roundtripping' feature that allows preservation of these custom additions in subsequent file generations.

The roundtripping feature in camp will save any code in the file that falls between camp custom tags, and will add it to the newly-generated version of the file. Example usage:

    camp <adm.json> -c <path_to_existing_impl.c> -h <path_to_existing_impl.h>

The resulting generated impl.c and impl.h files will contain the custom code from the impl.c and impl.h files passed to camp.

Current acceptable custom tags are:

• custom function body (example above)
• custom includes (/* [START|STOP] CUSTOM INCLUDES HERE */)
• custom functions (/* [START|STOP] CUSTOM FUNCTIONS HERE */)

For custom function bodies, the included in the custom function tag must be the same as the one used in the ADM for the custom function to be copied over to the correct area of the new file.

CAmp Architecture

• template.json - Example JSON ADM template
• CAmpPython/ - contains all of the source code for camp
  • CAmpPython.py - Main script of camp. This script calls all necessary generators and handles user input
  • data/name_registry.cfg - Initial name registry configuration file installed with camp.
  • utils/name_registry.py - Fuctions for getting and setting values of the camp name registry.
  • generators/ - All generator scripts and their utility functions
  • create_ace.py - Generates ACE tool input file
  • create_agent.py - Generates agent file (C code) for usage in NASA ION
  • create_gen_h.py - Generates the shared header file needed for NASA ION
  • create_impl_c.py - Generates the implementation file (C code) for usage in DTNMA C agent
  • create_impl_h.py - Generates the header file for the implementation file created by create_impl_c.py
  • create_mgr_c.py - Generates the manager file for usage in DTNMA C agent
  • create_mysql.py - Generates an SQL file for usage with DTNMA C agent stored procedures
  • lib/ - Library functions for generating commonly-used patterns and accessing portions of the ADM.
    • campch.py - library functions commonly needed specifically for C code generators.
    • campch_roundtrip.py - round-tripping functions
    • common/ - Library functions helpful to all generators.
    • campsettings.py - initializes various global variables for camp (enumerations for portions of the ADM, etc.)
    • camputil.py - utility functions for parsing the JSON input file and creating ARIs. Contains the Retriever class, which is used by all generators to access ADM data
    • jsonutil.py - utility functions to validate JSON input.

Adding Generators

To add a new generator to camp, create a python script that creates the file and add it to the CAmpPython/generators/ directory. Then, in CAmpPython.py, import the new generator and add it to the file generation code of the main() function (starting at line 105).

All generators should:

• define a create() method as their main function, which takes as its first and second argument:
  1. a Retriever object (pre-populated with the ADM passed to camp)
  2. a string that represents the path to the output directory
• utilize the Retriever object to access fields of the JSON ADM
• place generated file(s) in the output directory passed as the second argument to the create() function (the generator may choose to make a sub-directory in the output directory)

Contributing

To contribute to this project, through issue reporting or change requests, see the CONTRIBUTING document.