db: Add api.available_metrics function

kwollect/tools/kwollect_setup_db.py

@@ -391,6 +391,60 @@ except spiexceptions.QueryCanceled:
 
 $$ LANGUAGE 'plpython3u' IMMUTABLE;
 
+
+DROP FUNCTION IF EXISTS api.available_metrics;
+CREATE OR REPLACE FUNCTION api.available_metrics(
+  at          TIMESTAMPTZ       DEFAULT NOW(),
+  params      JSONB             DEFAULT '{{}}'
+)
+RETURNS TABLE (device_id TEXT, metric_id TEXT) AS $$
+DECLARE
+from_devices    TEXT[]    := NULL;
+from_job_id     INT       := NULL;
+from_job_id_end TIMESTAMP := NULL;
+BEGIN
+IF params->>'job_id' IS NOT NULL THEN
+  SELECT nullif(substring(params->>'job_id' FROM '^\d+$'), '')::int INTO from_job_id;
+  IF from_job_id IS NOT NULL THEN
+    SELECT MAX(stop_time) FROM nodetime_by_job WHERE job_id = from_job_id INTO from_job_id_end;
+    SELECT ARRAY(SELECT DISTINCT node FROM nodetime_by_job WHERE nodetime_by_job.job_id = from_job_id) INTO from_devices;
+    RETURN QUERY SELECT * FROM api.available_metrics(at => LEAST(from_job_id_end, at), params => jsonb_build_object('devices', array_to_json(from_devices)));
+    RETURN;
+  END IF;
+END IF;
+IF params->'devices' IS NOT NULL THEN
+  IF jsonb_typeof(params->'devices') = 'array' THEN
+    SELECT ARRAY(SELECT jsonb_array_elements_text(params->'devices')) INTO STRICT from_devices;
+  ELSE
+    RAISE EXCEPTION 'Cannot parse params->devices, should be JSON array';
+  END IF;
+END IF;
+RETURN QUERY
+WITH av_metrics AS (
+  SELECT metrics.device_id, metrics.metric_id
+  FROM metrics AS metrics WHERE
+  timestamp < at AND timestamp > at - INTERVAL '1m'
+  AND CASE WHEN from_devices IS NOT NULL THEN metrics.device_id = ANY (from_devices) ELSE true END
+  UNION
+  SELECT metrics.labels ->> '_device_alias'::text AS device_id, metrics.metric_id
+  FROM metrics AS metrics
+  WHERE metrics.labels ? '_device_alias'
+  AND timestamp < at AND timestamp > at - INTERVAL '1m'
+  AND CASE WHEN from_devices IS NOT NULL THEN metrics.labels->>'_device_alias' = ANY (from_devices) ELSE true END
+),
+ordered_metrics AS (
+  SELECT DISTINCT ON (idx1, idx2, idx3, metric_id)
+    metrics.device_id, metrics.metric_id,
+    CASE WHEN metrics.device_id ~ '^[a-z]+-\d+$' THEN '1' ELSE '2' END AS idx1,
+    (STRING_TO_ARRAY(metrics.device_id, '-'))[1] AS idx2,
+    COALESCE(SUBSTRING((STRING_TO_ARRAY(metrics.device_id, '-'))[2] FROM '([0-9]+)')::INTEGER, 0) as idx3
+  FROM av_metrics AS metrics
+)
+SELECT m.device_id, m.metric_id FROM ordered_metrics AS m;
+END;
+$$ LANGUAGE plpgsql IMMUTABLE;
+
+
 CREATE OR REPLACE FUNCTION api.insert_metrics(
   device_id   TEXT,
   metric_id   TEXT,