global bigtable connection for functions

Change-Id: Ib61bd2e9f4a19e1f8405491c572ef6b36c54142e

event_database/cloud_functions/readrow.go

@@ -2,17 +2,13 @@
 package p
 
 import (
-	"context"
 	"encoding/json"
 	"fmt"
 	"html"
 	"io"
 	"log"
 	"net/http"
-	"os"
 	"strings"
-
-	"cloud.google.com/go/bigtable"
 )
 
 // fetch a single row by the row key
@@ -109,20 +105,6 @@ func ReadRow(w http.ResponseWriter, r *http.Request) {
 	}
 	rowKey = emitterChain + ":" + emitterAddress + ":" + sequence
 
-	clientOnce.Do(func() {
-		// Declare a separate err variable to avoid shadowing client.
-		var err error
-		project := os.Getenv("GCP_PROJECT")
-		instance := os.Getenv("BIGTABLE_INSTANCE")
-		client, err = bigtable.NewClient(context.Background(), project, instance)
-		if err != nil {
-			http.Error(w, "Error initializing client", http.StatusInternalServerError)
-			log.Printf("bigtable.NewClient: %v", err)
-			return
-		}
-	})
-
-	tbl := client.Open("v2Events")
 	row, err := tbl.ReadRow(r.Context(), rowKey)
 	if err != nil {
 		http.Error(w, "Error reading rows", http.StatusInternalServerError)

event_database/cloud_functions/recent.go

@@ -9,7 +9,6 @@ import (
 	"io"
 	"log"
 	"net/http"
-	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -164,21 +163,6 @@ func Recent(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// create bibtable client and open table
-	clientOnce.Do(func() {
-		// Declare a separate err variable to avoid shadowing client.
-		var err error
-		project := os.Getenv("GCP_PROJECT")
-		instance := os.Getenv("BIGTABLE_INSTANCE")
-		client, err = bigtable.NewClient(context.Background(), project, instance)
-		if err != nil {
-			http.Error(w, "Error initializing client", http.StatusInternalServerError)
-			log.Printf("bigtable.NewClient: %v", err)
-			return
-		}
-	})
-	tbl := client.Open("v2Events")
-
 	// use the groupBy value to determine how many segements of the rowkey should be used for indexing results.
 	keySegments := 0
 	if groupBy == "chain" {

event_database/cloud_functions/shared.go

@@ -1,7 +1,10 @@
 package p
 
 import (
+	"context"
+	"log"
 	"net/http"
+	"os"
 	"strings"
 	"sync"
 
@@ -14,6 +17,27 @@ import (
 // every request.
 var client *bigtable.Client
 var clientOnce sync.Once
+var tbl *bigtable.Table
+
+// init runs during cloud function initialization. So, this will only run during an
+// an instance's cold start.
+// https://cloud.google.com/functions/docs/bestpractices/networking#accessing_google_apis
+func init() {
+	clientOnce.Do(func() {
+		// Declare a separate err variable to avoid shadowing client.
+		var err error
+		project := os.Getenv("GCP_PROJECT")
+		instance := os.Getenv("BIGTABLE_INSTANCE")
+		client, err = bigtable.NewClient(context.Background(), project, instance)
+		if err != nil {
+			// http.Error(w, "Error initializing client", http.StatusInternalServerError)
+			log.Printf("bigtable.NewClient error: %v", err)
+
+			return
+		}
+	})
+	tbl = client.Open("v2Events")
+}
 
 var columnFamilies = []string{"MessagePublication", "Signatures", "VAAState", "QuorumState"}
 

event_database/cloud_functions/totals.go

@@ -9,7 +9,6 @@ import (
 	"io"
 	"log"
 	"net/http"
-	"os"
 	"strconv"
 	"strings"
 	"sync"
@@ -235,21 +234,6 @@ func Totals(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// create bibtable client and open table
-	clientOnce.Do(func() {
-		// Declare a separate err variable to avoid shadowing client.
-		var err error
-		project := os.Getenv("GCP_PROJECT")
-		instance := os.Getenv("BIGTABLE_INSTANCE")
-		client, err = bigtable.NewClient(context.Background(), project, instance)
-		if err != nil {
-			http.Error(w, "Error initializing client", http.StatusInternalServerError)
-			log.Printf("bigtable.NewClient: %v", err)
-			return
-		}
-	})
-	tbl := client.Open("v2Events")
-
 	// create the rowkey prefix for querying
 	prefix := ""
 	if forChain != "" {

event_database/cloud_functions/transaction.go

@@ -2,14 +2,12 @@
 package p
 
 import (
-	"context"
 	"encoding/json"
 	"fmt"
 	"html"
 	"io"
 	"log"
 	"net/http"
-	"os"
 
 	"cloud.google.com/go/bigtable"
 )
@@ -75,21 +73,6 @@ func Transaction(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
 	}
 
-	// create bibtable client and open table
-	clientOnce.Do(func() {
-		// Declare a separate err variable to avoid shadowing client.
-		var err error
-		project := os.Getenv("GCP_PROJECT")
-		instance := os.Getenv("BIGTABLE_INSTANCE")
-		client, err = bigtable.NewClient(context.Background(), project, instance)
-		if err != nil {
-			http.Error(w, "Error initializing client", http.StatusInternalServerError)
-			log.Printf("bigtable.NewClient: %v", err)
-			return
-		}
-	})
-	tbl := client.Open("v2Events")
-
 	var result bigtable.Row
 	readErr := tbl.ReadRows(r.Context(), bigtable.PrefixRange(""), func(row bigtable.Row) bool {