Referential: Raise an error if the table lock times out

Paired with Johan on this one. There's an internal timeout on our table
lock. If it's reached, an
`ActiveRecord::StatementInvalid<PG::LockNotAvailable>` error is raised.
Use a custom error instead by "overriding" `#save` with a method that
raises our custom error in that case instead. This will enable us to
provide a custom user-facing error in the event this happens.

Refs #5024

2 files changed, 13 insertions, 0 deletions

diff --git a/app/errors/table_lock_timeout_error.rb b/app/errors/table_lock_timeout_error.rb
new file mode 100644
index 000000000..102f3a4a0
--- /dev/null
+++ b/app/errors/table_lock_timeout_error.rb
@@ -0,0 +1 @@
+class TableLockTimeoutError < ActiveRecord::StatementInvalid; end
diff --git a/app/models/referential.rb b/app/models/referential.rb
index b14ab3827..b44bb15c6 100644
--- a/app/models/referential.rb
+++ b/app/models/referential.rb
@@ -61,6 +61,18 @@ class Referential < ActiveRecord::Base
   scope :order_by_validity_period, ->(dir) { joins(:metadatas).order("unnest(periodes) #{dir}") }
   scope :order_by_lines, ->(dir) { joins(:metadatas).group("referentials.id").order("sum(array_length(referential_metadata.line_ids,1)) #{dir}") }
 
+  def save_with_table_lock_timeout
+    save_without_table_lock_timeout
+  rescue ActiveRecord::StatementInvalid => e
+    if e.message.include?('PG::LockNotAvailable')
+      raise TableLockTimeoutError.new(e)
+    else
+      raise
+    end
+  end
+
+  alias_method_chain :save, :table_lock_timeout
+
   def lines
     if metadatas.blank?
       workbench ? workbench.lines : associated_lines