From 94af70b112cb8bc06d5a3efef7212904fdcb11a3 Mon Sep 17 00:00:00 2001
From: Ivaylo Novakov <inovakov@gmail.com>
Date: Wed, 20 Apr 2022 20:20:11 +0200
Subject: [PATCH 1/2] Ignore "IndexNotFound" errors and log the rest without
 panicking.

---
 database/database.go | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/database/database.go b/database/database.go
index 77c86d36..4587ddc6 100644
--- a/database/database.go
+++ b/database/database.go
@@ -199,9 +199,8 @@ func ensureDBSchema(ctx context.Context, db *mongo.Database, schema map[string][
 	}
 	// Drop indexes we no longer need.
 	_, err = db.Collection(collUsers).Indexes().DropOne(ctx, "email_unique")
-	// Ignore namespace not found errors.
-	if err != nil && !strings.Contains(err.Error(), "NamespaceNotFound") {
-		return err
+	if err != nil && !strings.Contains(err.Error(), "IndexNotFound") {
+		log.Debugf("Error while dropping index '%s': %v", "email_unique", err)
 	}
 	// Ensure current schema.
 	for collName, models := range schema {

From 9be7072d286ccdc6c22f01dc6e43c7ce4fc1bc49 Mon Sep 17 00:00:00 2001
From: Ivaylo Novakov <inovakov@gmail.com>
Date: Thu, 21 Apr 2022 10:58:12 +0200
Subject: [PATCH 2/2] Ignore `NamespaceNotFound` errors while dropping indexes
 and add some comments explaining why we're handling errors like that.

---
 database/database.go | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/database/database.go b/database/database.go
index 4587ddc6..23d3511e 100644
--- a/database/database.go
+++ b/database/database.go
@@ -199,7 +199,17 @@ func ensureDBSchema(ctx context.Context, db *mongo.Database, schema map[string][
 	}
 	// Drop indexes we no longer need.
 	_, err = db.Collection(collUsers).Indexes().DropOne(ctx, "email_unique")
-	if err != nil && !strings.Contains(err.Error(), "IndexNotFound") {
+	// We want to ignore IndexNotFound errors - we'll have that each time we run
+	// this code after the initial run on which we drop the index.
+	// We also want to ignore NamespaceNotFound errors - we'll have that on the
+	// very first run of the service when users collection doesn't exist, yet.
+	// We don't want to worry new portal operators and waste their time.
+	// All other errors we want to log for informational purposes but we don't
+	// want to return an error and prevent the service from running - if there
+	// is any issue with the database that would affect the operation of the
+	// service, it will surface during the next step where we ensure collections
+	// indexes exist.
+	if err != nil && !strings.Contains(err.Error(), "IndexNotFound") && !strings.Contains(err.Error(), "NamespaceNotFound") {
 		log.Debugf("Error while dropping index '%s': %v", "email_unique", err)
 	}
 	// Ensure current schema.