Initial commit

This is a FastAPI backend microservice template used with `copier` utility.

Features of applied template are:
- Configuration file processing logic
- Metrics and tracing (both optional) configuration available
- Debug endpoints
- Database migration commands, prepared Alembic environment
- Database usage example in ping_db endpoint
- gitea sanity check pipeline

{{project_slug}}/observability/otel_agent.py.jinja

@@ -0,0 +1,46 @@
+"""Open Telemetry agent initialization is defined here"""
+
+from opentelemetry import metrics, trace
+from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
+from opentelemetry.exporter.prometheus import PrometheusMetricReader
+from opentelemetry.sdk.metrics import MeterProvider
+from opentelemetry.sdk.resources import SERVICE_NAME, SERVICE_VERSION, Resource
+from opentelemetry.sdk.trace import TracerProvider
+from opentelemetry.sdk.trace.export import BatchSpanProcessor
+
+from {{project_slug}}.config import JaegerConfig, PrometheusConfig
+from {{project_slug}}.version import VERSION as APP_VERSION
+
+from .metrics_server import PrometheusServer
+
+
+class OpenTelemetryAgent:  # pylint: disable=too-few-public-methods
+    def __init__(self, prometheus_config: PrometheusConfig | None, jaeger_config: JaegerConfig | None):
+        self._resource = Resource.create(
+            attributes={
+                SERVICE_NAME: "{{project_name}}",
+                SERVICE_VERSION: APP_VERSION,
+            }
+        )
+        self._prometheus: PrometheusServer | None = None
+        self._span_exporter: OTLPSpanExporter | None = None
+
+        if prometheus_config is not None:
+            self._prometheus = PrometheusServer(port=prometheus_config.port, host=prometheus_config.host)
+
+            reader = PrometheusMetricReader()
+            provider = MeterProvider(resource=self._resource, metric_readers=[reader])
+            metrics.set_meter_provider(provider)
+
+        if jaeger_config is not None:
+            self._span_exporter = OTLPSpanExporter(endpoint=jaeger_config.endpoint)
+
+            tracer_provider = TracerProvider(resource=self._resource)
+            processor = BatchSpanProcessor(span_exporter=self._span_exporter)
+            tracer_provider.add_span_processor(processor)
+            trace.set_tracer_provider(tracer_provider)
+
+    def shutdown(self) -> None:
+        """Stop metrics and tracing services if they were started."""
+        if self._prometheus is not None:
+            self._prometheus.shutdown()