Add instrumentation for the pgx package (#91)

* pgx driver instrumentation PoC

* Add instrumentation to README

* Update instrumentation/github.com/jackc/pgx/splunkpgx/sql_test.go

* Update instrumentation/github.com/jackc/pgx/splunkpgx/sql.go

Co-authored-by: Robert Pająk <[email protected]>

* Fix use of splunksql

* Add changes to changelog

* Add README

* Update example to be complete

* Add test module to validate end-to-end

* Fix CHANGELOG markdown syntax

* Fix docs on what import to replace

* Add test module to dependabot config

* Fix misspelling of conjunction

* Use testing cleanup

* Apply feedback

Co-authored-by: Robert Pająk <[email protected]>

Author: MrAlias

.github/dependabot.yml

@@ -30,6 +30,14 @@ updates:
     directory: "/instrumentation/github.com/go-sql-driver/mysql/splunkmysql/test"
     schedule:
       interval: "daily"
+  - package-ecosystem: "gomod"
+    directory: "/instrumentation/github.com/jackc/pgx/splunkpgx"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "gomod"
+    directory: "/instrumentation/github.com/jackc/pgx/splunkpgx/test"
+    schedule:
+      interval: "daily"
   - package-ecosystem: "gomod"
     directory: "/instrumentation/github.com/lib/pq/splunkpq"
     schedule:

CHANGELOG.md

@@ -13,6 +13,9 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add the
   `github.com/signalfx/splunk-otel-go/instrumentation/github.com/go-sql-driver/mysql/splunkmysql`
   instrumentation for the `github.com/go-sql-driver/mysql` package. (#90)
+- Add the
+  `github.com/signalfx/splunk-otel-go/instrumentation/github.com/jackc/pgx/splunkpgx`
+  instrumentation for the `github.com/jackc/pgx` package. (#91)
 - Add the
   `github.com/signalfx/splunk-otel-go/instrumentation/github.com/lib/pq/splunkpq`
   instrumentation for the `github.com/lib/pq` package. (#92)

README.md

@@ -103,6 +103,7 @@ Additional recommended Splunk specific instrumentations:
 - [`splunksql`](./instrumentation/database/sql/splunksql)
 - [`splunkhttp`](./instrumentation/net/http/splunkhttp)
 - [`splunkmysql`](./instrumentation/github.com/go-sql-driver/mysql/splunkmysql)
+- [`splunkpgx`](./instrumentation/github.com/jackc/pgx/splunkpgx)
 - [`splunkpq`](./instrumentation/github.com/lib/pq/splunkpq)
 
 ## Manual Instrumentation

instrumentation/github.com/jackc/pgx/splunkpgx/README.md

@@ -0,0 +1,16 @@
+# Splunk Instrumentation for the PostgreSQL Driver Package pgx
+
+[![Go Reference](https://pkg.go.dev/badge/github.com/signalfx/splunk-otel-go/instrumentation/github.com/jackc/pgx/splunkpgx.svg)](https://pkg.go.dev/github.com/signalfx/splunk-otel-go/instrumentation/github.com/jackc/pgx/splunkpgx)
+
+This package instruments the
+[`github.com/jackc/pgx`](https://github.com/jackc/pgx) package using the
+[`splunksql`](../../../../database/sql/splunksql) package.
+
+## Getting Started
+
+This package is design to be a drop-in replacement for the existing use of the
+`pgx` package when it is used in conjunction with the `database/sql` package.
+The blank identified import of `github.com/jackc/pgx/v4/stdlib` can be replaced
+with this package, and the standard library `sql.Open` function can be replaced
+with the equivalent `Open` from `splunksql`. An example can be found
+[here](./example_test.go).

instrumentation/github.com/jackc/pgx/splunkpgx/example_test.go

@@ -0,0 +1,94 @@
+// Copyright Splunk Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package splunkpgx_test
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/signalfx/splunk-otel-go/distro"
+	"github.com/signalfx/splunk-otel-go/instrumentation/database/sql/splunksql"
+
+	// Make sure to import this so the instrumented driver is registered.
+	_ "github.com/signalfx/splunk-otel-go/instrumentation/github.com/jackc/pgx/splunkpgx"
+)
+
+type server struct {
+	DB *sql.DB
+}
+
+func (s *server) listenAndServe() error {
+	// Requests to /square/n will return the square of n.
+	http.HandleFunc("/square/", s.handle)
+	return http.ListenAndServe(":80", nil)
+}
+
+func (s *server) handle(w http.ResponseWriter, req *http.Request) {
+	idx := strings.LastIndex(req.URL.Path, "/")
+	n, err := strconv.Atoi(req.URL.Path[idx+1:])
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	query := "SELECT squareNumber FROM squarenum WHERE number = ?"
+	var nSquared int
+	// Propagate the context to ensure created spans are included in any
+	// existing trace.
+	if err := s.DB.QueryRowContext(req.Context(), query, n).Scan(&nSquared); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	fmt.Fprintf(w, "%d", nSquared)
+}
+
+func Example() {
+	// Setup the Splunk OTel Go distribution.
+	sdk, err := distro.Run()
+	if err != nil {
+		panic(err)
+	}
+	// Ensure all spans are flushed before the application exits.
+	defer func() {
+		sErr := sdk.Shutdown(context.Background())
+		if sErr != nil {
+			panic(sErr)
+		}
+	}()
+
+	// Create a traced connection to the Postgres database.
+	db, err := splunksql.Open("pgx", "postgres://localhost:5432/dbname")
+	if err != nil {
+		panic(err)
+	}
+	defer db.Close()
+
+	// Validate DSN data by opening a connection. There is no parent context
+	// to pass here so the span created from this operation will be in its own
+	// trace.
+	if err := db.Ping(); err != nil {
+		panic(err)
+	}
+
+	srv := &server{DB: db}
+	if err := srv.listenAndServe(); err != nil {
+		panic(err)
+	}
+}

instrumentation/github.com/jackc/pgx/splunkpgx/go.mod

@@ -0,0 +1,17 @@
+module github.com/signalfx/splunk-otel-go/instrumentation/github.com/jackc/pgx/splunkpgx
+
+go 1.15
+
+require (
+	github.com/jackc/fake v0.0.0-20150926172116-812a484cc733 // indirect
+	github.com/jackc/pgx v3.6.2+incompatible
+	github.com/jackc/pgx/v4 v4.13.0
+	github.com/signalfx/splunk-otel-go v0.6.0
+	github.com/signalfx/splunk-otel-go/instrumentation/database/sql/splunksql v0.0.0-00010101000000-000000000000
+	github.com/stretchr/testify v1.7.0
+)
+
+replace (
+	github.com/signalfx/splunk-otel-go => ../../../../..
+	github.com/signalfx/splunk-otel-go/instrumentation/database/sql/splunksql => ../../../../database/sql/splunksql
+)