Add a logger to stat_database collector to get better handle on error

(also clean up some metric validity checks) Signed-off-by: Felix Yuan <felix.yuan@reddit.com>

Author: Sticksman

collector/pg_stat_database.go

@@ -17,6 +17,8 @@ import (
 "context"
 "database/sql"
 
+"github.com/go-kit/log"
+"github.com/go-kit/log/level"
 "github.com/prometheus/client_golang/prometheus"
 )
 
@@ -26,10 +28,12 @@ func init() {
 registerCollector(statDatabaseSubsystem, defaultEnabled, NewPGStatDatabaseCollector)
 }
 
-type PGStatDatabaseCollector struct{}
+type PGStatDatabaseCollector struct {
+log log.Logger
+}
 
 func NewPGStatDatabaseCollector(config collectorConfig) (Collector, error) {
-return &PGStatDatabaseCollector{}, nil
+return &PGStatDatabaseCollector{log: config.logger}, nil
 }
 
 var (
@@ -228,7 +232,7 @@ var (
 `
 )
 
-func (PGStatDatabaseCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
+func (c *PGStatDatabaseCollector) Update(ctx context.Context, instance *instance, ch chan<- prometheus.Metric) error {
 db := instance.getDB()
 rows, err := db.QueryContext(ctx,
 statDatabaseQuery,
@@ -267,217 +271,203 @@ func (PGStatDatabaseCollector) Update(ctx context.Context, instance *instance, c
 if err != nil {
 return err
 }
-datidLabel := "unknown"
-if datid.Valid {
-datidLabel = datid.String
+
+if !datid.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no datid")
+continue
 }
-datnameLabel := "unknown"
-if datname.Valid {
-datnameLabel = datname.String
+if !datname.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no datname")
+continue
 }
-
-numBackendsMetric := 0.0
-if numBackends.Valid {
-numBackendsMetric = numBackends.Float64
+if !numBackends.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no numbackends")
+continue
+}
+if !xactCommit.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no xact_commit")
+continue
+}
+if !xactRollback.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no xact_rollback")
+continue
+}
+if !blksRead.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no blks_read")
+continue
+}
+if !blksHit.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no blks_hit")
+continue
+}
+if !tupReturned.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no tup_returned")
+continue
+}
+if !tupFetched.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no tup_fetched")
+continue
+}
+if !tupInserted.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no tup_inserted")
+continue
+}
+if !tupUpdated.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no tup_updated")
+continue
+}
+if !tupDeleted.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no tup_deleted")
+continue
+}
+if !conflicts.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no conflicts")
+continue
+}
+if !tempFiles.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no temp_files")
+continue
+}
+if !tempBytes.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no temp_bytes")
+continue
+}
+if !deadlocks.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no deadlocks")
+continue
+}
+if !blkReadTime.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no blk_read_time")
+continue
+}
+if !blkWriteTime.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no blk_write_time")
+continue
+}
+if !statsReset.Valid {
+level.Debug(c.log).Log("msg", "Skipping collecting metric because it has no stats_reset")
+continue
 }
+
+labels := []string{datid.String, datname.String}
+
 ch <- prometheus.MustNewConstMetric(
 statDatabaseNumbackends,
 prometheus.GaugeValue,
-numBackendsMetric,
-datidLabel,
-datnameLabel,
+numBackends.Float64,
+labels...,
 )
 
-xactCommitMetric := 0.0
-if xactCommit.Valid {
-xactCommitMetric = xactCommit.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseXactCommit,
 prometheus.CounterValue,
-xactCommitMetric,
-datidLabel,
-datnameLabel,
+xactCommit.Float64,
+labels...,
 )
 
-xactRollbackMetric := 0.0
-if xactRollback.Valid {
-xactRollbackMetric = xactRollback.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseXactRollback,
 prometheus.CounterValue,
-xactRollbackMetric,
-datidLabel,
-datnameLabel,
+xactRollback.Float64,
+labels...,
 )
 
-blksReadMetric := 0.0
-if blksRead.Valid {
-blksReadMetric = blksRead.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseBlksRead,
 prometheus.CounterValue,
-blksReadMetric,
-datidLabel,
-datnameLabel,
+blksRead.Float64,
+labels...,
 )
 
-blksHitMetric := 0.0
-if blksHit.Valid {
-blksHitMetric = blksHit.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseBlksHit,
 prometheus.CounterValue,
-blksHitMetric,
-datidLabel,
-datnameLabel,
+blksHit.Float64,
+labels...,
 )
 
-tupReturnedMetric := 0.0
-if tupReturned.Valid {
-tupReturnedMetric = tupReturned.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTupReturned,
 prometheus.CounterValue,
-tupReturnedMetric,
-datidLabel,
-datnameLabel,
+tupReturned.Float64,
+labels...,
 )
 
-tupFetchedMetric := 0.0
-if tupFetched.Valid {
-tupFetchedMetric = tupFetched.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTupFetched,
 prometheus.CounterValue,
-tupFetchedMetric,
-datidLabel,
-datnameLabel,
+tupFetched.Float64,
+labels...,
 )
 
-tupInsertedMetric := 0.0
-if tupInserted.Valid {
-tupInsertedMetric = tupInserted.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTupInserted,
 prometheus.CounterValue,
-tupInsertedMetric,
-datidLabel,
-datnameLabel,
+tupInserted.Float64,
+labels...,
 )
 
-tupUpdatedMetric := 0.0
-if tupUpdated.Valid {
-tupUpdatedMetric = tupUpdated.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTupUpdated,
 prometheus.CounterValue,
-tupUpdatedMetric,
-datidLabel,
-datnameLabel,
+tupUpdated.Float64,
+labels...,
 )
 
-tupDeletedMetric := 0.0
-if tupDeleted.Valid {
-tupDeletedMetric = tupDeleted.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTupDeleted,
 prometheus.CounterValue,
-tupDeletedMetric,
-datidLabel,
-datnameLabel,
+tupDeleted.Float64,
+labels...,
 )
 
-conflictsMetric := 0.0
-if conflicts.Valid {
-conflictsMetric = conflicts.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseConflicts,
 prometheus.CounterValue,
-conflictsMetric,
-datidLabel,
-datnameLabel,
+conflicts.Float64,
+labels...,
 )
 
-tempFilesMetric := 0.0
-if tempFiles.Valid {
-tempFilesMetric = tempFiles.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTempFiles,
 prometheus.CounterValue,
-tempFilesMetric,
-datidLabel,
-datnameLabel,
+tempFiles.Float64,
+labels...,
 )
 
-tempBytesMetric := 0.0
-if tempBytes.Valid {
-tempBytesMetric = tempBytes.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseTempBytes,
 prometheus.CounterValue,
-tempBytesMetric,
-datidLabel,
-datnameLabel,
+tempBytes.Float64,
+labels...,
 )
 
-deadlocksMetric := 0.0
-if deadlocks.Valid {
-deadlocksMetric = deadlocks.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseDeadlocks,
 prometheus.CounterValue,
-deadlocksMetric,
-datidLabel,
-datnameLabel,
+deadlocks.Float64,
+labels...,
 )
 
-blkReadTimeMetric := 0.0
-if blkReadTime.Valid {
-blkReadTimeMetric = blkReadTime.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseBlkReadTime,
 prometheus.CounterValue,
-blkReadTimeMetric,
-datidLabel,
-datnameLabel,
+blkReadTime.Float64,
+labels...,
 )
 
-blkWriteTimeMetric := 0.0
-if blkWriteTime.Valid {
-blkWriteTimeMetric = blkWriteTime.Float64
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseBlkWriteTime,
 prometheus.CounterValue,
-blkWriteTimeMetric,
-datidLabel,
-datnameLabel,
+blkWriteTime.Float64,
+labels...,
 )
 
-statsResetMetric := 0.0
-if statsReset.Valid {
-statsResetMetric = float64(statsReset.Time.Unix())
-}
 ch <- prometheus.MustNewConstMetric(
 statDatabaseStatsReset,
 prometheus.CounterValue,
-statsResetMetric,
-datidLabel,
-datnameLabel,
+float64(statsReset.Time.Unix()),
+labels...,
 )
 }
 return nil