Merge pull request #15 from modern-python/12-feature-add-prometheus-instrument

add prometheus instrument

Author: lesnik512

lite_bootstrap/__init__.py

@@ -3,6 +3,7 @@
     FastAPIHealthChecksInstrument,
     FastAPILoggingInstrument,
     FastAPIOpenTelemetryInstrument,
+    FastAPIPrometheusInstrument,
     FastAPISentryInstrument,
 )
 from lite_bootstrap.bootstrappers.free_bootstrapper import FreeBootstrapper
@@ -11,6 +12,7 @@
     LitestarHealthChecksInstrument,
     LitestarLoggingInstrument,
     LitestarOpenTelemetryInstrument,
+    LitestarPrometheusInstrument,
     LitestarSentryInstrument,
 )
 from lite_bootstrap.instruments.healthchecks_instrument import HealthChecksInstrument
@@ -25,13 +27,15 @@
     "FastAPIHealthChecksInstrument",
     "FastAPILoggingInstrument",
     "FastAPIOpenTelemetryInstrument",
+    "FastAPIPrometheusInstrument",
     "FastAPISentryInstrument",
     "FreeBootstrapper",
     "HealthChecksInstrument",
     "LitestarBootstrapper",
     "LitestarHealthChecksInstrument",
     "LitestarLoggingInstrument",
     "LitestarOpenTelemetryInstrument",
+    "LitestarPrometheusInstrument",
     "LitestarSentryInstrument",
     "LoggingInstrument",
     "OpenTelemetryInstrument",

lite_bootstrap/bootstrappers/fastapi_bootstrapper.py

@@ -2,10 +2,13 @@
 import dataclasses
 import typing
 
+from prometheus_fastapi_instrumentator import Instrumentator
+
 from lite_bootstrap.bootstrappers.base import BaseBootstrapper
 from lite_bootstrap.instruments.healthchecks_instrument import HealthChecksInstrument, HealthCheckTypedDict
 from lite_bootstrap.instruments.logging_instrument import LoggingInstrument
 from lite_bootstrap.instruments.opentelemetry_instrument import OpenTelemetryInstrument
+from lite_bootstrap.instruments.prometheus_instrument import PrometheusInstrument
 from lite_bootstrap.instruments.sentry_instrument import SentryInstrument
 from lite_bootstrap.service_config import ServiceConfig
 
@@ -65,6 +68,27 @@ def teardown(self, application: fastapi.FastAPI | None = None) -> None:
 class FastAPISentryInstrument(SentryInstrument): ...
 
 
+@dataclasses.dataclass(kw_only=True, frozen=True)
+class FastAPIPrometheusInstrument(PrometheusInstrument):
+    metrics_path: str = "/metrics"
+    metrics_include_in_schema: bool = False
+    instrumentator_params: dict[str, typing.Any] = dataclasses.field(default_factory=dict)
+    instrument_params: dict[str, typing.Any] = dataclasses.field(default_factory=dict)
+    expose_params: dict[str, typing.Any] = dataclasses.field(default_factory=dict)
+
+    def bootstrap(self, _: ServiceConfig, application: fastapi.FastAPI | None = None) -> None:
+        if application:
+            Instrumentator(**self.instrumentator_params).instrument(
+                application,
+                **self.instrument_params,
+            ).expose(
+                application,
+                endpoint=self.metrics_path,
+                include_in_schema=self.metrics_include_in_schema,
+                **self.expose_params,
+            )
+
+
 @dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
 class FastAPIBootstrapper(BaseBootstrapper[fastapi.FastAPI, fastapi.FastAPI]):
     bootstrap_object: fastapi.FastAPI
@@ -73,6 +97,7 @@ class FastAPIBootstrapper(BaseBootstrapper[fastapi.FastAPI, fastapi.FastAPI]):
         | FastAPISentryInstrument
         | FastAPIHealthChecksInstrument
         | FastAPILoggingInstrument
+        | FastAPIPrometheusInstrument
     ]
     service_config: ServiceConfig
 

lite_bootstrap/bootstrappers/litestar_bootstrapper.py

@@ -2,10 +2,13 @@
 import dataclasses
 import typing
 
+from litestar.plugins.prometheus import PrometheusConfig, PrometheusController
+
 from lite_bootstrap.bootstrappers.base import BaseBootstrapper
 from lite_bootstrap.instruments.healthchecks_instrument import HealthChecksInstrument, HealthCheckTypedDict
 from lite_bootstrap.instruments.logging_instrument import LoggingInstrument
 from lite_bootstrap.instruments.opentelemetry_instrument import OpenTelemetryInstrument
+from lite_bootstrap.instruments.prometheus_instrument import PrometheusInstrument
 from lite_bootstrap.instruments.sentry_instrument import SentryInstrument
 from lite_bootstrap.service_config import ServiceConfig
 
@@ -63,6 +66,26 @@ def bootstrap(self, service_config: ServiceConfig, app_config: AppConfig | None
 class LitestarSentryInstrument(SentryInstrument): ...
 
 
+@dataclasses.dataclass(kw_only=True, frozen=True)
+class LitestarPrometheusInstrument(PrometheusInstrument):
+    additional_params: dict[str, typing.Any] = dataclasses.field(default_factory=dict)
+
+    def bootstrap(self, service_config: ServiceConfig, app_config: AppConfig | None = None) -> None:
+        class LitestarPrometheusController(PrometheusController):
+            path = self.metrics_path
+            include_in_schema = self.metrics_include_in_schema
+            openmetrics_format = True
+
+        litestar_prometheus_config = PrometheusConfig(
+            app_name=service_config.service_name,
+            **self.additional_params,
+        )
+
+        if app_config:
+            app_config.route_handlers.append(LitestarPrometheusController)
+            app_config.middleware.append(litestar_prometheus_config.middleware)
+
+
 @dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
 class LitestarBootstrapper(BaseBootstrapper[AppConfig, litestar.Litestar]):
     bootstrap_object: AppConfig
@@ -71,6 +94,7 @@ class LitestarBootstrapper(BaseBootstrapper[AppConfig, litestar.Litestar]):
         | LitestarSentryInstrument
         | LitestarHealthChecksInstrument
         | LitestarLoggingInstrument
+        | LitestarPrometheusInstrument
     ]
     service_config: ServiceConfig
 

lite_bootstrap/instruments/prometheus_instrument.py

@@ -0,0 +1,22 @@
+import dataclasses
+import re
+import typing
+
+from lite_bootstrap.instruments.base import BaseInstrument
+from lite_bootstrap.service_config import ServiceConfig
+
+
+VALID_PATH_PATTERN: typing.Final = re.compile(r"^(/[a-zA-Z0-9_-]+)+/?$")
+
+
+def _is_valid_path(maybe_path: str) -> bool:
+    return bool(re.fullmatch(VALID_PATH_PATTERN, maybe_path))
+
+
+@dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
+class PrometheusInstrument(BaseInstrument):
+    metrics_path: str = "/metrics"
+    metrics_include_in_schema: bool = False
+
+    def is_ready(self, _: ServiceConfig) -> bool:
+        return bool(self.metrics_path) and _is_valid_path(self.metrics_path)

pyproject.toml

@@ -52,8 +52,11 @@ fastapi = [
 fastapi-otl = [
     "opentelemetry-instrumentation-fastapi",
 ]
+fastapi-metrics = [
+    "prometheus-fastapi-instrumentator>=6.1",
+]
 fastapi-all = [
-    "lite-bootstrap[sentry,otl,logging,fastapi,fastapi-otl]"
+    "lite-bootstrap[sentry,otl,logging,fastapi,fastapi-otl,fastapi-metrics]"
 ]
 litestar = [
     "litestar>=2.9",

tests/test_fastapi_bootstrap.py

@@ -9,6 +9,7 @@
     FastAPIHealthChecksInstrument,
     FastAPILoggingInstrument,
     FastAPIOpenTelemetryInstrument,
+    FastAPIPrometheusInstrument,
     FastAPISentryInstrument,
     ServiceConfig,
 )
@@ -35,6 +36,7 @@ def test_fastapi_bootstrap(fastapi_app: FastAPI, service_config: ServiceConfig)
                 path="/health/",
             ),
             FastAPILoggingInstrument(logging_buffer_capacity=0),
+            FastAPIPrometheusInstrument(),
         ],
     )
     bootstrapper.bootstrap()
@@ -46,3 +48,12 @@ def test_fastapi_bootstrap(fastapi_app: FastAPI, service_config: ServiceConfig)
         assert response.json() == {"health_status": True, "service_name": "microservice", "service_version": "2.0.0"}
     finally:
         bootstrapper.teardown()
+
+
+def test_fastapi_prometheus_instrument(fastapi_app: FastAPI, service_config: ServiceConfig) -> None:
+    prometheus_instrument = FastAPIPrometheusInstrument(metrics_path="/custom-metrics-path")
+    prometheus_instrument.bootstrap(service_config, fastapi_app)
+
+    response = TestClient(fastapi_app).get(prometheus_instrument.metrics_path)
+    assert response.status_code == status.HTTP_200_OK
+    assert response.text

tests/test_litestar_bootstrap.py

@@ -9,6 +9,7 @@
     LitestarHealthChecksInstrument,
     LitestarLoggingInstrument,
     LitestarOpenTelemetryInstrument,
+    LitestarPrometheusInstrument,
     LitestarSentryInstrument,
     ServiceConfig,
 )
@@ -36,6 +37,7 @@ def test_litestar_bootstrap(service_config: ServiceConfig) -> None:
                 path="/health/",
             ),
             LitestarLoggingInstrument(logging_buffer_capacity=0),
+            LitestarPrometheusInstrument(),
         ],
     )
     application = bootstrapper.bootstrap()
@@ -52,3 +54,19 @@ def test_litestar_bootstrap(service_config: ServiceConfig) -> None:
             }
     finally:
         bootstrapper.teardown()
+
+
+def test_litestar_prometheus_bootstrap(service_config: ServiceConfig) -> None:
+    app_config = AppConfig()
+    prometheus_instrument = LitestarPrometheusInstrument(metrics_path="/custom-metrics-path")
+    bootstrapper = LitestarBootstrapper(
+        bootstrap_object=app_config,
+        service_config=service_config,
+        instruments=[prometheus_instrument],
+    )
+    application = bootstrapper.bootstrap()
+
+    with TestClient(app=application) as test_client:
+        response = test_client.get(prometheus_instrument.metrics_path)
+        assert response.status_code == status_codes.HTTP_200_OK
+        assert response.text