def test_returns_unmodified_if_no_variable_references(self):
config = {
collections.CompoundKey(["a", "b"]): "foo",
collections.CompoundKey(["a"]): "bar",
}
replaced = replace_variable_references(config)
assert config == replaced
def test_replaces_root_variable(self):
config = {
collections.CompoundKey(["a"]): "${b}",
collections.CompoundKey(["b"]): "foo",
}
replaced = replace_variable_references(config)
assert (replaced[collections.CompoundKey(
["a"])] == replaced[collections.CompoundKey(["b"])])
def test_chained_variables(self):
config = {
collections.CompoundKey(["a"]): "${b}",
collections.CompoundKey(["b"]): "${c}",
collections.CompoundKey(["c"]): "bar",
}
replaced = replace_variable_references(config)
for value in replaced.values():
assert value == "bar"
def test_replaces_from_root_to_nested_keys(self):
config = {
collections.CompoundKey(["a"]): "${a.b}",
collections.CompoundKey(["a", "b"]): "foo",
}
replaced = replace_variable_references(config)
assert (replaced[collections.CompoundKey(
["a"])] == replaced[collections.CompoundKey(["a", "b"])])
def test_doesnt_modify_input(self):
config = {
collections.CompoundKey(["a", "b"]): "foo",
collections.CompoundKey(["a"]): "${a.b}",
}
before_config = {
collections.CompoundKey(["a", "b"]): "foo",
collections.CompoundKey(["a"]): "${a.b}",
}
replaced = replace_variable_references(config)
assert config == before_config
assert config != replaced
def test_array_replacement_missing_variable(self):
config = {
collections.CompoundKey(["a"]): "foo",
collections.CompoundKey(["b"]): ["${a}", "${a}", "${c}"],
}
replaced = replace_variable_references(config)
assert replaced[collections.CompoundKey(["b"])] == [
replaced[collections.CompoundKey(["a"])],
replaced[collections.CompoundKey(["a"])],
"",
]
def check_and_replace(flat_config: dict, value: str) -> Optional[str]:
match = INTERPOLATION_REGEX.search(value)
if not match:
return None
# the matched_string includes "${}"; the matched_key is just the inner value
matched_string = match.group(0)
matched_key = match.group(1)
# get the referenced key from the config value
ref_key = collections.CompoundKey(matched_key.split("."))
# get the value corresponding to the referenced key
ref_value = flat_config.get(ref_key, "")
# The configuration's value was just a reference and nothing else
if value == matched_string:
return ref_value
# The reference wasn't a valid reference, so to maintain consistency
# with the rest of the config API, a missing reference returns an
# empty string
# The value could either have multiple references, or
# be used to interpolate a larger string, such
# as a database URI or API request header
# Ex1) "postgresql+psycopg2://${username}:${password}@{host}:${port}/${dbname}"
# Ex2) "Bearer ${api_token}"
return value.replace(matched_string, str(ref_value), 1)
def load_environment_variables(
env_var_prefix: str,
) -> Dict[collections.CompoundKey, Any]:
flat_config = {}
for env_var, env_var_value in os.environ.items():
if not env_var.startswith(env_var_prefix + "__"):
continue
# Strips the prefix off the environment variable
env_var_option = env_var[len(env_var_prefix + "__") :]
# Make sure the result has at least one delimited section
# with a key
if "__" not in env_var:
continue
# Env vars with escaped characters are interpreted as a
# literal "\", which Python helpfuly escaped with a second "\".
# This step makes sure that the escaped characters are properly
# interpreted.
value = cast(str, env_var_value.encode().decode("unicode_escape"))
# Place the environment variable into the flat config
# as the compound key
config_option = collections.CompoundKey(env_var_option.lower().split("__"))
flat_config[config_option] = string_to_type(
cast(str, interpolate_env_vars(value))
)
return flat_config
def test_replaces_multiple_existing_variables(self):
config = {
collections.CompoundKey(["a"]): "${b}",
collections.CompoundKey(["b"]): "foo",
collections.CompoundKey(["c"]): "bar",
collections.CompoundKey(["d"]): "${c}",
}
replaced = replace_variable_references(config)
assert (replaced[collections.CompoundKey(
["a"])] == replaced[collections.CompoundKey(["b"])])
assert (replaced[collections.CompoundKey(
["c"])] == replaced[collections.CompoundKey(["d"])])
def test_single_key_multiple_variables(self):
same_values = "${b}-${b}"
different_values = "${b}-${c}"
config = {
collections.CompoundKey(["a"]): same_values,
collections.CompoundKey(["d"]): different_values,
collections.CompoundKey(["b"]): "foo",
collections.CompoundKey(["c"]): "bar",
}
replaced = replace_variable_references(config)
assert replaced[collections.CompoundKey(
["a"])] == "{val}-{val}".format(
val=replaced[collections.CompoundKey(["b"])])
assert replaced[collections.CompoundKey(["d"])] == "{b}-{c}".format(
b=replaced[collections.CompoundKey(["b"])],
c=replaced[collections.CompoundKey(["c"])],
)
def test_bad_reference_returns_empty_string(self):
config = {
collections.CompoundKey(["a"]): "${b}",
collections.CompoundKey(["c"]): "bar",
collections.CompoundKey(["d"]): "${c}",
}
replaced = replace_variable_references(config)
assert replaced[collections.CompoundKey(["a"])] == ""
# not modifying the other, valid entries
assert replaced[collections.CompoundKey(["c"])] == "bar"
assert (replaced[collections.CompoundKey(
["d"])] == replaced[collections.CompoundKey(["c"])])
def test_flatten_dict(nested_dict):
flat = collections.dict_to_flatdict(nested_dict)
assert flat == {
collections.CompoundKey([1]): 2,
collections.CompoundKey([2, 1]): 2,
collections.CompoundKey([2, 3]): 4,
collections.CompoundKey([3, 1]): 2,
collections.CompoundKey([3, 3, 4]): 5,
collections.CompoundKey([3, 3, 6, 7]): 8,
}
def test_variable_reference_from_array(self):
config = {
collections.CompoundKey(["a"]): "foo",
collections.CompoundKey(["b"]): ["${a}", "${a}", "${a}"],
}
replaced = replace_variable_references(config)
assert replaced[collections.CompoundKey(["b"])] == [
replaced[collections.CompoundKey(["a"])],
replaced[collections.CompoundKey(["a"])],
replaced[collections.CompoundKey(["a"])],
]
def test_self_reference_doesnt_cause_recursion_error(self):
config = {
collections.CompoundKey(["a"]): "${a}",
}
replaced = replace_variable_references(config)
assert config == replaced