mdj2pdf

#!/usr/bin/python3

import argparse, os, sys, re, yaml, jinja2, subprocess, datetime

# Arguments

desc = '''
Convert a jinja2 templated markdown file into a PDF. Use the YAML metadata block
(https://pandoc.org/MANUAL.html#extension-yaml_metadata_block) to add variables
for templating.
'''

parser = argparse.ArgumentParser(description=desc)
parser.add_argument('file', help='jinja2 templated markdown file with yaml metadata block')
args = parser.parse_args()

# Read file

try:
    with open(args.file) as f:
        md = f.read()
except IOError as e:
    print(str(e), file=sys.stderr)
    exit(1)

# Parse YAML

now = datetime.datetime.now()

data = {
    'file': {
        'path': os.path.abspath(os.path.dirname(args.file)),
        'md': os.path.basename(args.file),
        'pdf': '%s.pdf' % os.path.splitext(os.path.basename(args.file))[0],
    },
    'now': {
        'year': now.year,
        'month': now.month,
        'day': now.day,
        'hour': now.hour,
        'minute': now.minute,
        'second': now.second,
    }
}

for yml in re.findall(r'(\A|^$\n)^---$\n(.*?)^(---|\.\.\.)$', md, re.MULTILINE+re.DOTALL):
    try:
        data.update(yaml.safe_load(yml[1]))
    except Exception as e:
        print(str(e), file=sys.stderr)
        exit(1)

# Parse Jinja2

try:
    j2 = jinja2.Environment(loader=jinja2.FileSystemLoader(data['file']['path']), undefined=jinja2.StrictUndefined, trim_blocks=True)
    # read file again (instead of string in var "md") to have a better trace on errors in jinja2
    doc = j2.get_template(data['file']['md']).render(data)
except Exception as e:
    import traceback
    print('%s:\n%s' % (str(e), traceback.format_exc()), file=sys.stderr)
    exit(1)

# Pass to pandoc

try:
    with open('/tmp/pandoc-preamble.tex', 'w') as fp:
        fp.write('''
            \\usepackage{fontspec}
            \\directlua{luaotfload.add_fallback
               ("emojifallback",
                {
                  "NotoColorEmoji:mode=harf;"
                }
               )}
            
            \\setmainfont{lmroman10-regular}[
              Extension      = .otf,
              BoldFont       = lmroman10-bold,
              ItalicFont     = lmroman10-italic,
              BoldItalicFont = lmroman10-bolditalic,
              RawFeature={fallback=emojifallback}
            ]
        ''')
    with subprocess.Popen(['pandoc', '-f', 'markdown', '-t', 'latex', '--pdf-engine=lualatex', '-H', '/tmp/pandoc-preamble.tex', '-s', '-o', data['file']['pdf']], stdin=subprocess.PIPE) as p:
        p.stdin.write(str.encode(doc))
except Exception as e:
    print(str(e), file=sys.stderr)
    exit(1)

exit(p.returncode)