update-version-for-test-push.py

#!/usr/bin/env python3
# vim: ts=4 sw=4 et
# coding: -*- utf-8 -*-

# © 2021 The Board of Trustees of the Leland Stanford Junior University.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import datetime
import logging
import logging.config
import os
import pathlib
from sys import exit
from typing import *

# Configure program logging
log_level = 'INFO'
if 'LOG_LEVEL' in os.environ:
    log_level = os.environ['LOG_LEVEL']
logging.config.dictConfig({
    "version": 1,
    "formatters": {
        "basic": {"format": "[%(levelname)s] %(message)s"}
    },
    "handlers": {
        "stderr": {
            "class": "logging.StreamHandler",
            "stream": "ext://sys.stderr",
            "formatter": "basic",
        },
    },
     "loggers": {"": {"level": log_level, "handlers": ["stderr"]}}
})

# Set up logging
logger = logging.getLogger()
debug = logger.debug
info = logger.info
error = logger.error

# Open up the version file
version_path = pathlib.Path('VERSION')
debug(f"Opening file {version_path}")
version_file = version_path.open(mode='r+', encoding='ascii')

# Read in the version string, and try splitting our version into three parts.
debug('Reading version line')
version_string = version_file.readline().rstrip("\n")
try:
    (a, b, c) = version_string.split('.')
except ValueError:
    error(f"Version '{version_string}' is not in the expected three-part form")
    exit(1)
info(f"Old version number was {a}.{b}.{c}")

# Convert the versions to int.
try:
    a = int(a)
    b = int(b)
    c = int(c)
except ValueError:
    error(f"Unable to parse '{a}', '{b}', or '{c}' as integers.")
    exit(1)

# Transform the version number.
# If the version is a.b.0, then we convert to a.{b-1}.99
# If the version is a.b.c, where c!=0, then we convert to a.b.{c-1}.99
d = None
if c == 0:
    b -= 1
    c = 99
else:
    c -= 1
    d = 99
# If b was zero, we might have just dropped it to -1.
# In that case, change b to 99, and reduce a.
if b < 0:
    a -= 1
    b = 99
# If a has been dropped to -1, that means both a _and_ b were 0.
# In that case, something is wrong.
if a < 0:
    error(f"a was dropped to below 0.  b={b} & c={c}.")
    exit(1)

# Construct a string for the version number.
# We start with a, b, and c.  If d is set, append it.
# We then append the UTC datetime, to the second.
# NOTE: This can trigger a race condition, if multiple pushes happen around the
# same time.  If that happens, I'm sorry, I hope you (future me?) gets a laugh
# out of it!
version_string = f"{a}.{b}.{c}"
if d is not None:
    version_string += f".{d}"
version_string += ('.' + datetime.datetime.utcnow().strftime('%Y%m%d%H%M%S'))
info(f"New version number is {version_string}")

# Seek back and truncate the version file
debug('Preparing for write')
version_file.seek(os.SEEK_SET, 0)
version_file.truncate(0)

# Write out the new version, and close.
debug('Writing out new version')
version_file.write(f"{version_string}\n")
version_file.close()

# That's it!
exit(0)