Add a `fallback_application_name` to the PostgreSQL DSN.

builtin/providers/postgresql/config.go

@@ -3,6 +3,7 @@ package postgresql
 import (
 	"database/sql"
 	"fmt"
+	"log"
 
 	_ "github.com/lib/pq" //PostgreSQL db
 )
@@ -15,6 +16,7 @@ type Config struct {
 	Password        string
 	SslMode         string
 	Timeout         int
+	ApplicationName string
 }
 
 // Client struct holding connection string
@@ -25,8 +27,12 @@ type Client struct {
 
 // NewClient returns new client config
 func (c *Config) NewClient() (*Client, error) {
-	connStr := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=postgres sslmode=%s connect_timeout=%d", c.Host, c.Port, c.Username, c.Password, c.SslMode, c.Timeout)
+	const dsnFmt = "host=%s port=%d user=%s password=%s sslmode=%s fallback_application_name=%s connect_timeout=%d"
 
+	logDSN := fmt.Sprintf(dsnFmt, c.Host, c.Port, c.Username, "<redacted>", c.SSLMode, c.ApplicationName)
+	log.Printf("[INFO] PostgreSQL DSN: `%s`", logDSN)
+
+	connStr := fmt.Sprintf(dsnFmt, c.Host, c.Port, c.Username, c.Password, c.SSLMode, c.ApplicationName, c.Timeout)
 	client := Client{
 		connStr:  connStr,
 		username: c.Username,

builtin/providers/postgresql/provider.go

@@ -1,6 +1,9 @@
 package postgresql
 
 import (
+	"bytes"
+	"fmt"
+
 	"github.com/hashicorp/errwrap"
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/terraform"
@@ -70,6 +73,7 @@ func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 		Password:        d.Get("password").(string),
 		Timeout:         d.Get("connect_timeout").(int),
 		SslMode:         d.Get("sslmode").(string),
+		ApplicationName: tfAppName(),
 	}
 
 	client, err := config.NewClient()
@@ -79,3 +83,16 @@ func providerConfigure(d *schema.ResourceData) (interface{}, error) {
 
 	return client, nil
 }
+
+func tfAppName() string {
+	const VersionPrerelease = terraform.VersionPrerelease
+	var versionString bytes.Buffer
+
+	fmt.Fprintf(&versionString, "'Terraform v%s", terraform.Version)
+	if terraform.VersionPrerelease != "" {
+		fmt.Fprintf(&versionString, "-%s", terraform.VersionPrerelease)
+	}
+	fmt.Fprintf(&versionString, "'")
+
+	return versionString.String()
+}