From f6705b879abafd7db07885fa282d55ed0c896528 Mon Sep 17 00:00:00 2001
From: mike12345567 <me@michaeldrury.co.uk>
Date: Fri, 10 Dec 2021 15:10:45 +0000
Subject: [PATCH] Reducing the load on DB caused by CouchDB all_db when working
 with a large number of couch databases.

---
 packages/auth/src/db/utils.js | 45 +++++++++++++++++++++++++++++------
 packages/auth/src/helpers.js  |  9 +++++++
 2 files changed, 47 insertions(+), 7 deletions(-)
 create mode 100644 packages/auth/src/helpers.js

diff --git a/packages/auth/src/db/utils.js b/packages/auth/src/db/utils.js
index d23d407dab..7ced405c82 100644
--- a/packages/auth/src/db/utils.js
+++ b/packages/auth/src/db/utils.js
@@ -3,10 +3,15 @@ const Replication = require("./Replication")
 const { DEFAULT_TENANT_ID, Configs } = require("../constants")
 const env = require("../environment")
 const { StaticDatabases, SEPARATOR, DocumentTypes } = require("./constants")
-const { getTenantId, getTenantIDFromAppID } = require("../tenancy")
+const {
+  getTenantId,
+  getTenantIDFromAppID,
+  getGlobalDBName,
+} = require("../tenancy")
 const fetch = require("node-fetch")
 const { getCouch } = require("./index")
 const { getAppMetadata } = require("../cache/appMetadata")
+const { checkSlashesInUrl } = require("../helpers")
 
 const NO_APP_ERROR = "No app provided"
 
@@ -194,6 +199,10 @@ exports.getCouchUrl = () => {
   return `${protocol}://${env.COUCH_DB_USERNAME}:${env.COUCH_DB_PASSWORD}@${rest}`
 }
 
+exports.getStartEndKeyURL = (base, baseKey, tenantId = "") => {
+  return `${base}?startkey="${baseKey}${SEPARATOR}${tenantId}"&endkey="${baseKey}${SEPARATOR}${tenantId}${UNICODE_MAX}"`
+}
+
 /**
  * if in production this will use the CouchDB _all_dbs call to retrieve a list of databases. If testing
  * when using Pouch it will use the pouchdb-all-dbs package.
@@ -203,12 +212,34 @@ exports.getAllDbs = async () => {
   if (env.isTest()) {
     return getCouch().allDbs()
   }
-  const response = await fetch(`${exports.getCouchUrl()}/_all_dbs`)
-  if (response.status === 200) {
-    return response.json()
-  } else {
-    throw "Cannot connect to CouchDB instance"
+  let dbs = []
+  async function addDbs(url) {
+    const response = await fetch(checkSlashesInUrl(encodeURI(url)))
+    if (response.status === 200) {
+      let json = await response.json()
+      dbs = dbs.concat(json)
+    } else {
+      throw "Cannot connect to CouchDB instance"
+    }
   }
+  let couchUrl = `${exports.getCouchUrl()}_all_dbs`
+  if (env.MULTI_TENANCY) {
+    let tenantId = getTenantId()
+    // get prod apps
+    await addDbs(
+      exports.getStartEndKeyURL(couchUrl, DocumentTypes.APP, tenantId)
+    )
+    // get dev apps
+    await addDbs(
+      exports.getStartEndKeyURL(couchUrl, DocumentTypes.APP_DEV, tenantId)
+    )
+    // add global db name
+    dbs.push(getGlobalDBName(tenantId))
+  } else {
+    // just get all DBs in self host
+    await addDbs(couchUrl)
+  }
+  return dbs
 }
 
 /**
@@ -389,7 +420,7 @@ const getScopedFullConfig = async function (db, { type, user, workspace }) {
 }
 
 const getPlatformUrl = async settings => {
-  let platformUrl = env.PLATFORM_URL
+  let platformUrl = env.PLATFORM_URL || "http://localhost:10000"
 
   if (!env.SELF_HOSTED && env.MULTI_TENANCY) {
     // cloud and multi tenant - add the tenant to the default platform url
diff --git a/packages/auth/src/helpers.js b/packages/auth/src/helpers.js
new file mode 100644
index 0000000000..b402a82cf3
--- /dev/null
+++ b/packages/auth/src/helpers.js
@@ -0,0 +1,9 @@
+/**
+ * Makes sure that a URL has the correct number of slashes, while maintaining the
+ * http(s):// double slashes.
+ * @param {string} url The URL to test and remove any extra double slashes.
+ * @return {string} The updated url.
+ */
+exports.checkSlashesInUrl = url => {
+  return url.replace(/(https?:\/\/)|(\/)+/g, "$1$2")
+}