Add scope to ExclusiveLease clear and document the rake taskgitlab-ee-4910-exclusive-lease

3 files changed, 33 insertions, 5 deletions

diff --git a/doc/administration/raketasks/maintenance.md b/doc/administration/raketasks/maintenance.md
index ecf92c379fd..2b4252a7b1d 100644
--- a/doc/administration/raketasks/maintenance.md
+++ b/doc/administration/raketasks/maintenance.md
@@ -240,3 +240,31 @@ sudo gitlab-rake gitlab:tcp_check[example.com,80]
 cd /home/git/gitlab
 sudo -u git -H bundle exec rake gitlab:tcp_check[example.com,80] RAILS_ENV=production
 ```
+
+## Clear exclusive lease (DANGER)
+
+GitLab uses a shared lock mechanism: `ExclusiveLease` to prevent simultaneous operations
+in a shared resource. An example is running periodic garbage collection on repositories.
+
+In very specific situations, a operation locked by an Exclusive Lease can fail without
+releasing the lock. If you can't wait for it to expire, you can run this task to manually
+clear it.
+
+To clear all exclusive leases:
+
+DANGER: **DANGER**: 
+Don't run it while GitLab or Sidekiq is running
+
+```bash
+sudo gitlab-rake gitlab:exclusive_lease:clear
+```
+
+To specify a lease `type` or lease `type + id`, specify a scope:
+
+```bash
+# to clear all leases for repository garbage collection:
+sudo gitlab-rake gitlab:exclusive_lease:clear[project_housekeeping:*]
+
+# to clear a lease for repository garbage collection in a specific project: (id=4)
+sudo gitlab-rake gitlab:exclusive_lease:clear[project_housekeeping:4]
+```
diff --git a/lib/gitlab/exclusive_lease.rb b/lib/gitlab/exclusive_lease.rb
index d928301c011..12b5e240962 100644
--- a/lib/gitlab/exclusive_lease.rb
+++ b/lib/gitlab/exclusive_lease.rb
@@ -43,9 +43,9 @@ module Gitlab
 
     # Removes any existing exclusive_lease from redis
     # Don't run this in a live system without making sure no one is using the leases
-    def self.reset_all!
+    def self.reset_all!(scope = '*')
       Gitlab::Redis::SharedState.with do |redis|
-        redis.scan_each(match: redis_shared_state_key('*')).each do |key|
+        redis.scan_each(match: redis_shared_state_key(scope)).each do |key|
           redis.del(key)
         end
       end
diff --git a/lib/tasks/gitlab/exclusive_lease.rake b/lib/tasks/gitlab/exclusive_lease.rake
index 27582819e0b..83722bf6d94 100644
--- a/lib/tasks/gitlab/exclusive_lease.rake
+++ b/lib/tasks/gitlab/exclusive_lease.rake
@@ -1,8 +1,8 @@
 namespace :gitlab do
   namespace :exclusive_lease do
-    desc 'GitLab | Clear existing exclusive leases'
-    task clear: :environment do
-      Gitlab::ExclusiveLease.reset_all!
+    desc 'GitLab | Clear existing exclusive leases for specified scope (default: *)'
+    task :clear, [:scope] => [:environment] do |_, args|
+      args[:scope].nil? ? Gitlab::ExclusiveLease.reset_all! : Gitlab::ExclusiveLease.reset_all!(args[:scope])
       puts 'All exclusive lease entries were removed.'
     end
   end