feat: implement environment-variable based config (open-feature#62)

Signed-off-by: Federico Bond <[email protected]>

Author: federicobond

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/config.py

@@ -0,0 +1,31 @@
+import os
+import typing
+
+
+def str_to_bool(val: str) -> bool:
+    return val.lower() == "true"
+
+
+def env_or_default(env_var, default, cast=None):
+    val = os.environ.get(env_var)
+    if val is None:
+        return default
+    return val if cast is None else cast(val)
+
+
+class Config:
+    def __init__(
+        self,
+        host: typing.Optional[str] = None,
+        port: typing.Optional[str] = None,
+        tls: typing.Optional[bool] = None,
+        timeout: typing.Optional[int] = None,
+    ):
+        self.host = env_or_default("FLAGD_HOST", "localhost") if host is None else host
+        self.port = (
+            env_or_default("FLAGD_PORT", 8013, cast=int) if port is None else port
+        )
+        self.tls = (
+            env_or_default("FLAGD_TLS", False, cast=str_to_bool) if tls is None else tls
+        )
+        self.timeout = 5 if timeout is None else timeout

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/defaults.py

@@ -39,7 +39,7 @@
 from openfeature.flag_evaluation import FlagEvaluationDetails
 from openfeature.provider.provider import AbstractProvider
 
-from .defaults import Defaults
+from .config import Config
 from .flag_type import FlagType
 from .proto.schema.v1 import schema_pb2, schema_pb2_grpc
 
@@ -54,10 +54,10 @@ class FlagdProvider(AbstractProvider):
 
     def __init__(
         self,
-        host: str = Defaults.HOST,
-        port: int = Defaults.PORT,
-        tls: bool = Defaults.TLS,
-        timeout: int = Defaults.TIMEOUT,
+        host: typing.Optional[str] = None,
+        port: typing.Optional[int] = None,
+        tls: typing.Optional[bool] = None,
+        timeout: typing.Optional[int] = None,
     ):
         """
         Create an instance of the FlagdProvider
@@ -67,13 +67,15 @@ def __init__(
         :param tls: enable/disable secure TLS connectivity
         :param timeout: the maximum to wait before a request times out
         """
-        self.host = host
-        self.port = port
-        self.tls = tls
-        self.timeout = timeout
+        self.config = Config(
+            host=host,
+            port=port,
+            tls=tls,
+            timeout=timeout,
+        )
 
         channel_factory = grpc.secure_channel if tls else grpc.insecure_channel
-        self.channel = channel_factory(f"{host}:{port}")
+        self.channel = channel_factory(f"{self.config.host}:{self.config.port}")
         self.stub = schema_pb2_grpc.ServiceStub(self.channel)
 
     def shutdown(self):
@@ -131,7 +133,7 @@ def _resolve(
         evaluation_context: EvaluationContext,
     ):
         context = self._convert_context(evaluation_context)
-        call_args = {"timeout": self.timeout}
+        call_args = {"timeout": self.config.timeout}
         try:
             if flag_type == FlagType.BOOLEAN:
                 request = schema_pb2.ResolveBooleanRequest(

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/provider.py

@@ -0,0 +1,29 @@
+from openfeature.contrib.provider.flagd.config import Config
+
+
+def test_return_default_values():
+    config = Config()
+    assert config.host == "localhost"
+    assert config.port == 8013
+    assert config.tls is False
+    assert config.timeout == 5
+
+
+def test_overrides_defaults_with_environment(monkeypatch):
+    monkeypatch.setenv("FLAGD_HOST", "flagd")
+    monkeypatch.setenv("FLAGD_PORT", "1234")
+    monkeypatch.setenv("FLAGD_TLS", "true")
+
+    config = Config()
+    assert config.host == "flagd"
+    assert config.port == 1234
+    assert config.tls is True
+
+
+def test_uses_arguments_over_environments_and_defaults(monkeypatch):
+    monkeypatch.setenv("FLAGD_HOST", "flagd")
+
+    config = Config(host="flagd2", port=12345, tls=True)
+    assert config.host == "flagd2"
+    assert config.port == 12345
+    assert config.tls is True