From 91f21f395d80a8e7f0c199cc0f110547a08188be Mon Sep 17 00:00:00 2001
From: Will Franklin <will@willpf.co.uk>
Date: Wed, 21 Jun 2023 11:08:09 +0100
Subject: [PATCH] Add useful messages to config checks

---
 src/config/env.ts | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/config/env.ts b/src/config/env.ts
index 9d233f78d..ae11acf32 100644
--- a/src/config/env.ts
+++ b/src/config/env.ts
@@ -2,19 +2,23 @@ import { strict as assert } from "assert";
 
 export function s(name: string, def?: string): string {
   const value = process.env[name] || def;
-  assert(value !== undefined);
+  assert(value !== undefined, `Missing environment variable ${name}`);
   return value;
 }
 
 export function ss(name: string, def?: string[]): string[] {
   const value = process.env[name]?.split(",") || def;
-  assert(value !== undefined);
+  assert(value !== undefined, `Missing environment variable ${name}`);
   return value;
 }
 
 export function n(name: string, def?: number): number {
   const value = Number(process.env[name]) || def;
-  assert(value !== undefined && !isNaN(value));
+  assert(value !== undefined, `Missing environment variable ${name}`);
+  assert(
+    !isNaN(value),
+    `Invalid number for environment variable ${name}: ${process.env[name]}`
+  );
   return value;
 }
 
@@ -23,7 +27,10 @@ export function b(name: string, def?: boolean): boolean {
   if (value === undefined && def !== undefined) {
     return def;
   }
-  assert(value === "true" || value === "false");
+  assert(
+    value === "true" || value === "false",
+    `Invalid boolean for environment variable ${name}: ${value}`
+  );
   return value === "true";
 }
 
@@ -33,12 +40,20 @@ export function e<T extends readonly string[]>(
   def?: typeof options[number]
 ): typeof options[number] {
   const value = s(name, def);
-  assert(options.indexOf(value) !== -1);
+  assert(
+    options.indexOf(value) !== -1,
+    `Invalid value for environment variable ${name}: ${value}. Valid options are: ${options.join(
+      ", "
+    )}`
+  );
   return value;
 }
 
 export function json(name: string, def?: any): any {
   const value = process.env[name];
-  assert(value !== undefined || def !== undefined);
+  assert(
+    value !== undefined || def !== undefined,
+    `Missing environment variable ${name}`
+  );
   return value === undefined ? def : JSON.parse(value);
 }