Added prometheus client

Added scheduler for compute current spool metrics and info

spoolman/prometheus/metrics.py

@@ -0,0 +1,71 @@
+import sqlalchemy
+import logging
+
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import contains_eager
+
+from spoolman.database import models
+
+from prometheus_client import REGISTRY, make_asgi_app, Gauge
+
+PREFIX = "spoolman"
+
+SPOOL_PRICE = Gauge("%s_spool_price" % PREFIX, "Total Spool price", ['spool_id', 'filament_id'])
+SPOOL_USED_WEIGHT = Gauge("%s_spool_weight_used" % PREFIX, "Spool Used Weight", ['spool_id', 'filament_id'])
+FILAMENT_INFO = Gauge("%s_filament_info" % PREFIX, "Filament information", [
+            'filament_id',
+            'vendor',
+            'name',
+            'material',
+            'color'])
+FILAMENT_DENSITY = Gauge("%s_filament_density" % PREFIX, "Density of filament", ["filament_id"])
+FILAMENT_DIAMETER = Gauge("%s_filament_diameter" % PREFIX, "Diameter of filament", ["filament_id"])
+FILAMENT_WEIGHT = Gauge("%s_filament_weight" % PREFIX, "Net weight of filament", ["filament_id"])
+
+logger = logging.getLogger(__name__)
+
+
+def make_metrics_app():
+    registry = REGISTRY
+    logger.info("Start metrics app")
+    return make_asgi_app(registry=registry)
+
+
+metrics_app = make_metrics_app()
+
+
+async def spool_metrics(db: AsyncSession) -> None:
+    stmt = (
+        sqlalchemy.select(models.Spool)
+            .where(
+                sqlalchemy.or_(
+                    models.Spool.archived.is_(False),
+                    models.Spool.archived.is_(None),
+                )
+            )
+    )
+    rows = await db.execute(stmt)
+    result = list(rows.unique().scalars().all())
+    for row in result:
+        SPOOL_PRICE.labels(str(row.id), str(row.filament_id)).set(row.price)
+        SPOOL_USED_WEIGHT.labels(str(row.id), str(row.filament_id)).set(row.used_weight)
+
+
+async def filament_metrics(db: AsyncSession) -> None:
+    stmt = (
+        sqlalchemy.select(models.Filament)
+            .options(contains_eager(models.Filament.vendor))
+            .join(models.Filament.vendor, isouter=True)
+    )
+    rows = await db.execute(stmt)
+    result = list(rows.unique().scalars().all())
+    for row in result:
+        FILAMENT_INFO.labels(str(row.id),
+                             row.vendor.name,
+                             row.name,
+                             row.material,
+                             row.color_hex).set(1)
+        FILAMENT_DENSITY.labels(str(row.id)).set(row.density)
+        FILAMENT_DIAMETER.labels(str(row.id)).set(row.diameter)
+        FILAMENT_WEIGHT.labels(str(row.id)).set(row.weight)
+