From 7ddbff2669c10c5440b5853e65ee9682ba231492 Mon Sep 17 00:00:00 2001
From: Salvatore Novelli <salvatore.novelli@gmail.com>
Date: Thu, 7 Apr 2022 19:55:56 +0100
Subject: [PATCH] feat: add "application_name" as an optional DB option #1170
 (#1478)

* implemented changes to resolve issue 1170

* added applicationName to the list of db options in the documentation'

Co-authored-by: Daniele Casal <daniele.casal@lloydsbanking.com>
Co-authored-by: Sukhvinder Panesar <79143027+esspee-lbg@users.noreply.github.com>
---
 src/lib/__snapshots__/create-config.test.ts.snap | 1 +
 src/lib/create-config.ts                         | 1 +
 src/lib/db/db-pool.ts                            | 5 ++++-
 src/lib/types/option.ts                          | 1 +
 src/server-dev.ts                                | 1 +
 website/docs/deploy/configuring-unleash.md       | 1 +
 6 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/lib/__snapshots__/create-config.test.ts.snap b/src/lib/__snapshots__/create-config.test.ts.snap
index 609b84065b..790e727edd 100644
--- a/src/lib/__snapshots__/create-config.test.ts.snap
+++ b/src/lib/__snapshots__/create-config.test.ts.snap
@@ -11,6 +11,7 @@ Object {
   },
   "db": Object {
     "acquireConnectionTimeout": 30000,
+    "applicationName": "unleash",
     "database": "unleash_db",
     "disableMigration": false,
     "driver": "postgres",
diff --git a/src/lib/create-config.ts b/src/lib/create-config.ts
index 9ab90b57c6..dc0f6090be 100644
--- a/src/lib/create-config.ts
+++ b/src/lib/create-config.ts
@@ -95,6 +95,7 @@ const defaultDbOptions: IDBOption = {
     },
     schema: process.env.DATABASE_SCHEMA || 'public',
     disableMigration: false,
+    applicationName: process.env.DATABASE_APPLICATION_NAME || 'unleash',
 };
 
 const defaultSessionOption: ISessionOption = {
diff --git a/src/lib/db/db-pool.ts b/src/lib/db/db-pool.ts
index 0bcb943f9d..e59b18b6fe 100644
--- a/src/lib/db/db-pool.ts
+++ b/src/lib/db/db-pool.ts
@@ -9,7 +9,10 @@ export function createDb({
     return knex({
         client: 'pg',
         version: db.version,
-        connection: db,
+        connection: {
+            ...db,
+            application_name: db.applicationName,
+        },
         pool: db.pool,
         searchPath: db.schema,
         asyncStackTraces: true,
diff --git a/src/lib/types/option.ts b/src/lib/types/option.ts
index f0d6509fc4..185c662f61 100644
--- a/src/lib/types/option.ts
+++ b/src/lib/types/option.ts
@@ -30,6 +30,7 @@ export interface IDBOption {
     };
     schema: string;
     disableMigration: boolean;
+    applicationName?: string;
 }
 
 export interface ISessionOption {
diff --git a/src/server-dev.ts b/src/server-dev.ts
index 45bda849ca..d790a9e763 100644
--- a/src/server-dev.ts
+++ b/src/server-dev.ts
@@ -16,6 +16,7 @@ process.nextTick(async () => {
                     database: process.env.UNLEASH_DATABASE_NAME || 'unleash',
                     schema: process.env.UNLEASH_DATABASE_SCHEMA,
                     ssl: false,
+                    applicationName: 'unleash',
                 },
                 server: {
                     enableRequestLogger: true,
diff --git a/website/docs/deploy/configuring-unleash.md b/website/docs/deploy/configuring-unleash.md
index b6701a3d17..b2cc00c464 100644
--- a/website/docs/deploy/configuring-unleash.md
+++ b/website/docs/deploy/configuring-unleash.md
@@ -205,6 +205,7 @@ The available options are listed in the table below. Options can be specified ei
 | `pool.min`               | `DATABASE_POOL_MIN`             | 0              | The minimum number of connections in the connection pool.                                                                                                                                |
 | `pool.max`               | `DATABASE_POOL_MAX`             | 4              | The maximum number of connections in the connection pool.                                                                                                                                |
 | `pool.idleTimeoutMillis` | `DATABASE_POOL_IDLE_TIMEOUT_MS` | 30000          | The amount of time (in milliseconds) that a connection must be idle for before it is marked as a candidate for eviction.                                                                 |
+| `applicationName`        | `DATABASE_APPLICATION_NAME`     | `unleash`      | The name of the application that created this Client instance.                                                                                    |
 
 Alternatively, you can use a [libpq connection string](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING) to connect to the database. You can provide it directly or from a file by using one of the below options. In JavaScript, these are top-level properties of the root configuration object, *not* the `db` object.