makesecrets

#! /usr/bin/python
#
# Copyright 2020 Google LLC
#
# 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.

# usage:
#   makesecrets [VALUES_YML]
#
# Copies example-secrets.env to container/secrets/secrets.env.
#
# Optionally, VALUES_YML can be a YAML file containing values for some or all of
# the variables in example-secrets.env; for these variables, the generated file
# will contain the value from VALUES_YML, rather than the original value from
# example-secrets.env.  Any variables not mentioned in VALUES_YML will be copied
# unmodified.  Any variables in VALUES_YML which do not occur in
# example-secrets.env will be ignored; they will not appear in the generated
# file.

import yaml
import re
import sys
import os

values_yml = None

if len(sys.argv) > 2:
  print("usage: makesecrets [VALUES_YML]")
  sys.exit(-1)

if len(sys.argv) > 1:
  values_yml = sys.argv[1]

if values_yml != None:
  if not os.path.exists(values_yml):
    print("%s not found" % values_yml)
    sys.exit(-1)

if os.path.exists("container/secrets/secrets.env"):
  print("Cowardly refusing to overwrite existing file container/secrets/secrets.env.")
  print("If you really want to overwrite that file, delete it first.")
  sys.exit(-1)

if not os.path.exists("example-secrets.env"):
  print("File not found: example-secrets.env")
  sys.exit(-1)

data = {}
if values_yml != None:
  with open(values_yml, "r") as f:
    data = yaml.load(f, Loader=yaml.FullLoader)

if values_yml != None:
  print("Subsituting values from %s" % values_yml)

with open("container/secrets/secrets.env", "w") as fout:  
  with open("example-secrets.env", "r") as fin:
    for line in fin.readlines():
      line = line.rstrip()
      m = re.match(r'^export ([^=]+)=(.*)$', line)
      if m and m.group(1) in data:
        key = m.group(1)
        fout.write("export %s=\"%s\"\n" % (key, re.sub(r'"', '\\"', data[key])))
      else:
        fout.write("%s\n" % line)

print("Wrote ./container/secrets/secrets.env")