✨ translate ff calls to var calls in lieue of a mock provider

.changes/0.5.0.md

@@ -0,0 +1,3 @@
+## 0.5.0 - 2023-04-17
+### Changed
+* Translate all feature flag calls to var calls in the event no provider is used. This allows users to manage feature flags locally and seamlessly transition between that model and a dedicated provider.

.github/workflows/run-tests.yml

@@ -23,7 +23,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        dbt-version: ["1.0", "1.1", "1.2", "1.3"]
+        dbt-version: ["1.0", "1.1", "1.2", "1.3", "1.4"]
 
     steps:
       - name: Check out repo

CHANGELOG.md

@@ -6,6 +6,10 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html),
 and is generated by [Changie](https://github.com/miniscruff/changie).
 
 
+## 0.5.0 - 2023-04-17
+### Changed
+* Translate all feature flag calls to var calls in the event no provider is used. This allows users to manage feature flags locally and seamlessly transition between that model and a dedicated provider.
+
 ## 0.4.1 - 2022-11-06
 ### Added
 * CI testing across all dbt versions post 1.0 serving as both integration tests and functional tests

dbt_feature_flags/harness.py

@@ -24,8 +24,10 @@ def __init__(self):
         import os
 
         from featureflags.api.client import Client
-        from featureflags.api.default.get_all_segments import sync as retrieve_segments
-        from featureflags.api.default.get_feature_config import sync as retrieve_flags
+        from featureflags.api.default.get_all_segments import \
+            sync as retrieve_segments
+        from featureflags.api.default.get_feature_config import \
+            sync as retrieve_flags
         from featureflags.client import CfClient, Target
         from featureflags.client import log as logger
         from featureflags.config import Config

dbt_feature_flags/patch.py

@@ -11,11 +11,16 @@
 # 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.
+from __future__ import annotations
 
 import os
+import typing as t
 from enum import Enum
+from functools import wraps
 
-from dbt_feature_flags import base, harness, launchdarkly, mock
+from dbt_feature_flags import base, harness, launchdarkly
+
+_MOCK_CLIENT = object()
 
 
 class SupportedProviders(str, Enum):
@@ -24,56 +29,77 @@ class SupportedProviders(str, Enum):
     NoopClient = "mock"
 
 
-def _get_client() -> base.BaseFeatureFlagsClient:
-    """Return the user specified client, valid impementations MUST
-    inherit from BaseFeatureFlagsClient"""
-    ff_provider = os.getenv("FF_PROVIDER")
-    ff_client = None
-    if os.getenv("DBT_FF_DISABLE") or not ff_provider:
-        ff_client = mock.MockFeatureFlagClient()
-    elif ff_provider == SupportedProviders.Harness:
-        ff_client = harness.HarnessFeatureFlagsClient()
-    elif ff_provider == SupportedProviders.LaunchDarkly:
-        ff_client = launchdarkly.LaunchDarklyFeatureFlagsClient()
-    if not isinstance(ff_client, base.BaseFeatureFlagsClient):
-        raise RuntimeError(
-            "Invalid feature flag client specified by (FF_PROVIDER=%s)",
-            ff_provider,
-        )
-    return ff_client
-
+def _is_truthy(value: str) -> bool:
+    """Return True if the value is truthy, False otherwise."""
+    return value.lower() in ("1", "true", "yes")
 
-def patch_dbt_environment() -> None:
-    import functools
 
-    from dbt.clients import jinja
+def _get_client() -> base.BaseFeatureFlagsClient | _MOCK_CLIENT:
+    """Return the user specified client.
 
-    # Getting environment function from dbt
-    jinja._get_environment = jinja.get_environment
+    Valid implementations MUST inherit from BaseFeatureFlagsClient.
+    """
+    provider, client = os.getenv("DBT_FF_PROVIDER"), None
 
-    # FF client
-    ff_client = _get_client()
+    if _is_truthy(os.getenv("DBT_FF_DISABLE", "0")):
+        client = _MOCK_CLIENT
+    elif not provider:
+        client = _MOCK_CLIENT
+    elif provider == SupportedProviders.Harness:
+        client = harness.HarnessFeatureFlagsClient()
+    elif provider == SupportedProviders.LaunchDarkly:
+        client = launchdarkly.LaunchDarklyFeatureFlagsClient()
 
-    def add_ff_extension(func):
-        if getattr(func, "status", None) == "patched":
-            return func
-
-        @functools.wraps(func)
-        def with_ff_extension(*args, **kwargs):
-            env = func(*args, **kwargs)
-            env.globals["feature_flag"] = ff_client.bool_variation
-            env.globals["feature_flag_str"] = ff_client.string_variation
-            env.globals["feature_flag_num"] = ff_client.number_variation
-            env.globals["feature_flag_json"] = ff_client.json_variation
-            return env
+    if client is not _MOCK_CLIENT and not isinstance(
+        client, base.BaseFeatureFlagsClient
+    ):
+        raise RuntimeError(
+            "Invalid dbt feature flag client specified by (DBT_FF_PROVIDER=%s)",
+            provider,
+        )
 
-        with_ff_extension.status = "patched"
+    return client
+
+
+def get_rendered(
+    fn: t.Callable,
+    client: base.BaseFeatureFlagsClient,
+):
+    """Patch dbt's jinja environment to include feature flag functions."""
+
+    if getattr(fn, "status", None) == "patched":
+        return fn
+
+    @wraps(fn)
+    def _wrapped(
+        string: str,
+        ctx: t.Dict[str, t.Any],
+        node=None,
+        capture_macros: bool = False,
+        native: bool = False,
+    ):
+        if client is _MOCK_CLIENT:
+            ctx["feature_flag"] = ctx["var"]
+            ctx["feature_flag_str"] = ctx["var"]
+            ctx["feature_flag_num"] = ctx["var"]
+            ctx["feature_flag_json"] = ctx["var"]
+        else:
+            ctx["feature_flag"] = client.bool_variation
+            ctx["feature_flag_str"] = client.string_variation
+            ctx["feature_flag_num"] = client.number_variation
+            ctx["feature_flag_json"] = client.json_variation
+        return fn(string, ctx, node, capture_macros, native)
+
+    _wrapped.status = "patched"
+    return _wrapped
 
-        return with_ff_extension
 
-    env_with_ff = add_ff_extension(jinja._get_environment)
+def patch_dbt_environment() -> None:
+    """Patch dbt's jinja environment to include feature flag functions."""
+    from dbt.clients import jinja
 
-    jinja.get_environment = env_with_ff
+    jinja._get_rendered = jinja.get_rendered
+    jinja.get_rendered = get_rendered(jinja._get_rendered, _get_client())
 
 
 if __name__ == "__main__":

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "dbt-feature-flags"
-version = "0.4.1"
+version = "0.5.0"
 description = "Use feature flags in dbt models"
 authors = ["z3z1ma <butler.alex2010@gmail.com>"]
 include = ["zzz_dbt_feature_flags.pth"]

tests/test_dbt_feature_flags.py

@@ -2,11 +2,14 @@
 
 patch_dbt_environment()
 
+
 def test_ff_eval_1() -> None:
-    from dbt.clients.jinja import get_environment
+    from dbt.clients.jinja import get_rendered
+    from dbt.context.base import generate_base_context
 
-    template = get_environment().from_string(
-        """
+    assert (
+        get_rendered(
+            """
     {%- set test_case -%}
         {%- if feature_flag("Test_Flag", default=False) -%}
             select 100 as invalid
@@ -15,16 +18,20 @@ def test_ff_eval_1() -> None:
         {%- endif -%}
     {%- endset -%}
     {{- test_case | trim -}}
-    """
+    """,
+            generate_base_context({}),  # type: ignore
+        )
+        == "select -100 as valid"
     )
-    assert template.render() == "select -100 as valid"
 
 
 def test_ff_eval_2() -> None:
-    from dbt.clients.jinja import get_environment
+    from dbt.clients.jinja import get_rendered
+    from dbt.context.base import generate_base_context
 
-    template = get_environment().from_string(
-        """
+    assert (
+        get_rendered(
+            """
     {%- set test_case -%}
         {%- if feature_flag("Test_Flag", default=True) -%}
             select 100 as valid
@@ -33,16 +40,20 @@ def test_ff_eval_2() -> None:
         {%- endif -%}
     {%- endset -%}
     {{- test_case | trim -}}
-    """
+    """,
+            generate_base_context({}),  # type: ignore
+        )
+        == "select 100 as valid"
     )
-    assert template.render() == "select 100 as valid"
 
 
 def test_ff_eval_nested() -> None:
-    from dbt.clients.jinja import get_environment
+    from dbt.clients.jinja import get_rendered
+    from dbt.context.base import generate_base_context
 
-    template = get_environment().from_string(
-        """
+    assert (
+        get_rendered(
+            """
     {%- set test_case -%}
         {%- if feature_flag("Test_Flag", default=feature_flag("Nested_Flag", default=True)) -%}
             select 100 as valid
@@ -51,16 +62,20 @@ def test_ff_eval_nested() -> None:
         {%- endif -%}
     {%- endset -%}
     {{- test_case | trim -}}
-    """
+    """,
+            generate_base_context({}),  # type: ignore
+        )
+        == "select 100 as valid"
     )
-    assert template.render() == "select 100 as valid"
 
 
 def test_ff_eval_with_var() -> None:
     from dbt.clients.jinja import get_rendered
     from dbt.context.base import generate_base_context
-
-    assert get_rendered("""
+
+    assert (
+        get_rendered(
+            """
     {%- set test_case -%}
         {%- if feature_flag("Test_Flag", default=var("Dbt_Var", default=True)) -%}
             select 100 as valid
@@ -69,13 +84,20 @@ def test_ff_eval_with_var() -> None:
         {%- endif -%}
     {%- endset -%}
     {{- test_case | trim -}}
-    """, generate_base_context({})) == "select 100 as valid"
+    """,
+            generate_base_context({}),
+        )
+        == "select 100 as valid"
+    )
+
 
 def test_ff_eval_with_var_overriden_by_cli() -> None:
     from dbt.clients.jinja import get_rendered
     from dbt.context.base import generate_base_context
-
-    assert get_rendered("""
+
+    assert (
+        get_rendered(
+            """
     {%- set test_case -%}
         {%- if feature_flag("Test_Flag", default=var("Dbt_Var", default=True)) -%}
             select 100 as invalid
@@ -84,5 +106,8 @@ def test_ff_eval_with_var_overriden_by_cli() -> None:
         {%- endif -%}
     {%- endset -%}
     {{- test_case | trim -}}
-    """, generate_base_context({"Dbt_Var": False})) == "select -100 as valid"
-
+    """,
+            generate_base_context({"Dbt_Var": False}),
+        )
+        == "select -100 as valid"
+    )