Creating the framework for your parser

First, create a directory for your parser under the relevant parser project directory:

cd dependencies/parsers/<parserproject>
mkdir <parsername>

In the following please note the naming conventions:

• <parsername> - flat case, e.g., quantumespresso

• <ParserName> - Pascal case, e.g., QuantumEspresso

• <parser_name> - snake case, e.g., quantum_espresso

• <PARSERNAME> - upper flat case, e.g., QUANTUMESPRESSO

Parser files

In the following, <license> represents the insertion of the following license agreement statement:

#
# Copyright The NOMAD Authors.
#
# This file is part of NOMAD.
# See https://nomad-lab.eu for further info.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

The following are typical files found within a parser source directory:

• __init__.py

  <license>
  from .parser import <ParserName>Parser
  

• __main__.py

  <license>
  import sys
  import json
  import logging
  
  from nomad.utils import configure_logging
  from nomad.datamodel import EntryArchive
  from atomisticparsers.<parsername> import <ParserName>Parser
  
  if __name__ == "__main__":
      configure_logging(console_log_level=logging.DEBUG)
      archive = EntryArchive()
      <ParserName>Parser().parse(sys.argv[1], archive, logging)
      json.dump(archive.m_to_dict(), sys.stdout, indent=2)
  

• metainfo/__init__.py

  <license>
  from nomad.metainfo import Environment
  
  from . import <parsername>
  
  m_env = Environment()
  m_env.m_add_sub_section(Environment.packages, <parsername>.m_package)
  

• metainfo/<parser_name>.py - contains code-specific metadata definitions.

• nomad_plugin.yaml

  code_category: <Parserproject> code
  code_homepage: <>
  code_name: <PARSERNAME>
  metadata:
  codeCategory: <Parserproject> code
  codeLabel: <PARSERNAME>
  codeLabelStyle: All in capitals
  codeName: <parsername>
  codeUrl: <>
  parserDirName: dependencies/parsers/<parserproject>/<parserproject>parsers/parsername/
  parserGitUrl: https://github.com/nomad-coe/<parserproject>-parsers.git
  parserSpecific: ''
  preamble: ''
  status: production
  tableOfFiles: ''
  name: parsers/<parsername>
  parser_class_name: <parserproject>parsers.<parsername>.parser.<ParserName>Parser
  python_package: <parserproject>parsers.<parsername>
  

• parser.py - the parser source code.

• README.md - a short description of the functionality of this parser.

Integration into NOMAD's parser-matching interface

The nomad_plugin.yaml file enables the parser to be recognized as a plugin to the NOMAD software. However, in order for NOMAD to identify that it should use this parser, we still need to add configuration details within NOMAD's parser-matching interface. These options are specified within the plugins options (plugins = Plugins(options={}))) in the file nomad/config/__init__.py. There are many examples to follow here. In short, we need to create a dictionary key within options for our new parser:

'parsers/<parsername>': Parser(
    python_package='<parserproject>parsers.<parsername>',
    <args>
    )

Here, <args> can be one or several of the following:

• mainfile_name_re= - regex string for matching mainfile name
• mainfile_contents_re= - regex string for matching mainfile contents
• mainfile_mime_re= -
• supported_compressions= -
• mainfile_alternative= -
• mainfile_binary_header_re= -
• mainfile_contents_dict={'__has_all_keys': ['<key1>', '<key2>'}),
• parser_as_interface= -

You can find further information about this topic here: Examples of parser-matching