fix: prometheus with multiple providers

internal/build/build.go

@@ -8,10 +8,10 @@ import (
 )
 
 var (
-	Version              = "Version not set"
+	Version              = "version not set"
 	GitRevision          = "not set"
 	GitBranch            = "not set"
-	uiVersionDefaultText = "Viewer not build"
+	uiVersionDefaultText = "viewer not build"
 	Tags                 []string
 	Commands             = []string{"tegola"}
 )

provider/hana/hana.go

@@ -26,7 +26,12 @@ import (
 const Name = "hana"
 
 type connectionPoolCollector struct {
-	pool                     *sql.DB
+	pool *sql.DB
+
+	// providerName the pool is created for
+	// required to make metrics unique
+	providerName string
+
 	maxConnectionDesc        *prometheus.Desc
 	currentConnectionsDesc   *prometheus.Desc
 	availableConnectionsDesc *prometheus.Desc
@@ -106,28 +111,30 @@ func (c *connectionPoolCollector) Collectors(prefix string, _ func(configKey str
 		prefix+"hana_max_connections",
 		"Max number of hana connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
 
 	c.currentConnectionsDesc = prometheus.NewDesc(
 		prefix+"hana_current_connections",
 		"Current number of hana connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
 
 	c.availableConnectionsDesc = prometheus.NewDesc(
 		prefix+"hana_available_connections",
 		"Current number of available hana connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
+
 	return []observability.Collector{c}, nil
 }
 
 // Provider provides the HANA data provider.
 type Provider struct {
 	dbVersion uint
+	name      string
 	pool      *connectionPoolCollector
 	// map of layer name and corresponding sql
 	layers     map[string]Layer
@@ -387,10 +394,16 @@ func CreateProvider(config dict.Dicter, maps []provider.Map, providerType string
 		return nil, err
 	}
 
+	name, err := config.String(ConfigKeyName, nil)
+	if err != nil {
+		return nil, err
+	}
+
 	p := Provider{
+		name:      name,
 		dbVersion: uint(majorVersion),
 		srid:      uint64(srid),
-		pool:      &connectionPoolCollector{pool: conn},
+		pool:      &connectionPoolCollector{pool: conn, providerName: name},
 	}
 
 	layers, err := config.MapSlice(ConfigKeyLayers)
@@ -405,7 +418,7 @@ func CreateProvider(config dict.Dicter, maps []provider.Map, providerType string
 
 		lName, err := layer.String(ConfigKeyLayerName, nil)
 		if err != nil {
-			return nil, fmt.Errorf("For layer (%v) we got the following error trying to get the layer's name field: %w", i, err)
+			return nil, fmt.Errorf("for layer (%v) we got the following error trying to get the layer's name field: %w", i, err)
 		}
 
 		if j, ok := lyrsSeen[lName]; ok {
@@ -480,7 +493,7 @@ func CreateProvider(config dict.Dicter, maps []provider.Map, providerType string
 
 		if isSrsRoundEarth(p.pool, uint64(lsrid)) {
 			if !hasSrsPlanarEquivalent(p.pool, uint64(lsrid)) {
-				return nil, fmt.Errorf("Unable to find a planar equivalent for srid %v in layer: %v", lsrid, lName)
+				return nil, fmt.Errorf("unable to find a planar equivalent for srid %v in layer: %v", lsrid, lName)
 			}
 			lsrid = int(toPlanarEquivalenSrid(uint64(lsrid)))
 		}
@@ -562,7 +575,7 @@ func CreateProvider(config dict.Dicter, maps []provider.Map, providerType string
 				return nil, err
 			}
 
-			var clipGeom bool = true
+			var clipGeom = true
 			if clipGeom, err = layer.Bool(ConfigKeyClipGeometry, &clipGeom); err != nil {
 				return nil, err
 			}
@@ -665,6 +678,10 @@ func (p Provider) inspectLayerGeomType(pname string, l *Layer, maps []provider.M
 	}
 
 	fields, err := getFieldDescriptions(l.Name(), l.GeomFieldName(), l.IDFieldName(), columns, false)
+	if err != nil {
+		return err
+	}
+
 	rowValues := make([]interface{}, len(fields))
 
 	for rows.Next() {
@@ -681,7 +698,10 @@ func (p Provider) inspectLayerGeomType(pname string, l *Layer, maps []provider.M
 			}
 
 			value := *(rowValues[i].(*sql.NullString))
-			p.setLayerGeomType(l, strings.Trim(value.String, "ST_"))
+			err := p.setLayerGeomType(l, strings.Trim(value.String, "ST_"))
+			if err != nil {
+				return err
+			}
 
 			break
 		}

provider/postgis/postgis.go

@@ -34,6 +34,11 @@ const Name = "postgis"
 
 type connectionPoolCollector struct {
 	*pgxpool.Pool
+
+	// providerName the pool is created for
+	// required to make metrics unique
+	providerName string
+
 	maxConnectionDesc        *prometheus.Desc
 	currentConnectionsDesc   *prometheus.Desc
 	availableConnectionsDesc *prometheus.Desc
@@ -47,7 +52,7 @@ func (c connectionPoolCollector) Collect(ch chan<- prometheus.Metric) {
 	if c.Pool == nil {
 		return
 	}
-	stat := c.Pool.Stat()
+	stat := c.Stat()
 	ch <- prometheus.MustNewConstMetric(
 		c.maxConnectionDesc,
 		prometheus.GaugeValue,
@@ -73,33 +78,38 @@ func (c *connectionPoolCollector) Collectors(prefix string, _ func(configKey str
 		prefix = prefix + "_"
 	}
 
+	// a constant label ensures that the metrics are unique
+	// this allows the registration of multiple providers in the same
+	// config.
 	c.maxConnectionDesc = prometheus.NewDesc(
 		prefix+"postgres_max_connections",
 		"Max number of postgres connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
 
 	c.currentConnectionsDesc = prometheus.NewDesc(
 		prefix+"postgres_current_connections",
 		"Current number of postgres connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
 
 	c.availableConnectionsDesc = prometheus.NewDesc(
 		prefix+"postgres_available_connections",
 		"Current number of available postgres connections in the pool",
 		nil,
-		nil,
+		prometheus.Labels{"provider_name": c.providerName},
 	)
 	return []observability.Collector{c}, nil
 }
 
 // Provider provides the postgis data provider.
 type Provider struct {
 	config pgxpool.Config
+	name   string
 	pool   *connectionPoolCollector
+
 	// map of layer name and corresponding sql
 	layers     map[string]Layer
 	srid       uint64
@@ -122,31 +132,37 @@ func (p *Provider) Collectors(prefix string, cfgFn func(configKey string) map[st
 	}
 
 	buckets := []float64{.1, 1, 5, 20}
-	collectors, err := p.pool.Collectors(prefix, cfgFn)
+	c, err := p.pool.Collectors(prefix, cfgFn)
 	if err != nil {
 		return nil, err
 	}
 
+	// a constant label ensures that the metrics are unique
+	// this allows the registration of multiple providers in the same
+	// config.
+	// Additional label names will be appended to the constant labels.
 	p.mvtProviderQueryHistogramSeconds = prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
-			Name:    prefix + "_mvt_provider_sql_query_seconds",
-			Help:    "A histogram of query time for sql for mvt providers",
-			Buckets: buckets,
+			Name:        prefix + "_mvt_provider_sql_query_seconds",
+			Help:        "A histogram of query time for sql for mvt providers",
+			Buckets:     buckets,
+			ConstLabels: prometheus.Labels{"provider_name": p.name},
 		},
 		[]string{"map_name", "z"},
 	)
 
 	p.queryHistogramSeconds = prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
-			Name:    prefix + "_provider_sql_query_seconds",
-			Help:    "A histogram of query time for sql for providers",
-			Buckets: buckets,
+			Name:        prefix + "_provider_sql_query_seconds",
+			Help:        "A histogram of query time for sql for providers",
+			Buckets:     buckets,
+			ConstLabels: prometheus.Labels{"provider_name": p.name},
 		},
 		[]string{"map_name", "layer_name", "z"},
 	)
 
 	p.collectorsRegistered = true
-	return append(collectors, p.mvtProviderQueryHistogramSeconds, p.queryHistogramSeconds), nil
+	return append(c, p.mvtProviderQueryHistogramSeconds, p.queryHistogramSeconds), nil
 }
 
 const (
@@ -460,20 +476,26 @@ func CreateProvider(config dict.Dicter, maps []provider.Map, providerType string
 		return nil, err
 	}
 
+	name, err := config.String(ConfigKeyName, nil)
+	if err != nil {
+		return nil, err
+	}
+
 	if err = ConfigTLS(sslmode, sslkey, sslcert, sslrootcert, dbconfig); err != nil {
 		return nil, err
 	}
 
 	p := Provider{
 		srid:   uint64(srid),
 		config: *dbconfig,
+		name:   name,
 	}
 
 	pool, err := pgxpool.ConnectConfig(context.Background(), &p.config)
 	if err != nil {
 		return nil, fmt.Errorf("failed while creating connection pool: %w", err)
 	}
-	p.pool = &connectionPoolCollector{Pool: pool}
+	p.pool = &connectionPoolCollector{Pool: pool, providerName: name}
 
 	layers, err := config.MapSlice(ConfigKeyLayers)
 	if err != nil {

server/server.go

@@ -3,11 +3,12 @@ package server
 
 import (
 	"fmt"
-	"github.com/go-spatial/tegola/internal/build"
 	"net/http"
 	"net/url"
 	"path"
 
+	"github.com/go-spatial/tegola/internal/build"
+
 	"github.com/go-spatial/tegola/observability"
 
 	"github.com/dimfeld/httptreemux"
@@ -25,7 +26,7 @@ const (
 var (
 	// Version is the version of the software, this should be set by the main program, before starting up.
 	// It is used by various Middleware to determine the version.
-	Version string = "Version Not Set"
+	Version string = "version not set"
 
 	// HostName is the name of the host to use for construction of URLS.
 	// configurable via the tegola config.toml file (set in main.go)
@@ -71,7 +72,7 @@ func NewRouter(a *atlas.Atlas) *httptreemux.TreeMux {
 		)
 		if h := o.Handler(metricsRoute); h != nil {
 			// Only set up the /metrics endpoint if we have a configured observer
-			log.Infof("Setting up observer: %v", o.Name())
+			log.Infof("setting up observer: %v", o.Name())
 			group.UsingContext().Handler(http.MethodGet, metricsRoute, h)
 		}
 	}
@@ -98,7 +99,7 @@ func NewRouter(a *atlas.Atlas) *httptreemux.TreeMux {
 func Start(a *atlas.Atlas, port string) *http.Server {
 
 	// notify the user the server is starting
-	log.Infof("starting tegola server(%v) on port %v", build.Version, port)
+	log.Infof("starting tegola server (%v) on port %v", build.Version, port)
 
 	srv := &http.Server{Addr: port, Handler: NewRouter(a)}