From 1f6418f907c7074cf1c7ad2fa48fc583d3c6b0ac Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Wed, 26 Apr 2017 01:33:38 +0800
Subject: [PATCH] Track error message in `SchedulerStats`.

---
 app/models/scheduler_stat.rb                              | 1 +
 db/migrate/20170425172415_add_error_to_scheduler_stats.rb | 5 +++++
 lib/scheduler/manager.rb                                  | 8 ++++++--
 3 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 db/migrate/20170425172415_add_error_to_scheduler_stats.rb

diff --git a/app/models/scheduler_stat.rb b/app/models/scheduler_stat.rb
index 55dc8fda6ac..258a437f647 100644
--- a/app/models/scheduler_stat.rb
+++ b/app/models/scheduler_stat.rb
@@ -17,4 +17,5 @@ end
 #  live_slots_finish :integer
 #  started_at        :datetime         not null
 #  success           :boolean
+#  error             :text
 #
diff --git a/db/migrate/20170425172415_add_error_to_scheduler_stats.rb b/db/migrate/20170425172415_add_error_to_scheduler_stats.rb
new file mode 100644
index 00000000000..9d26ec29d74
--- /dev/null
+++ b/db/migrate/20170425172415_add_error_to_scheduler_stats.rb
@@ -0,0 +1,5 @@
+class AddErrorToSchedulerStats < ActiveRecord::Migration
+  def change
+    add_column :scheduler_stats, :error, :text
+  end
+end
diff --git a/lib/scheduler/manager.rb b/lib/scheduler/manager.rb
index 1846aa7669a..44317f7cc65 100644
--- a/lib/scheduler/manager.rb
+++ b/lib/scheduler/manager.rb
@@ -78,6 +78,8 @@ module Scheduler
         start = Time.now.to_f
         info = @mutex.synchronize { @manager.schedule_info(klass) }
         stat = nil
+        error = nil
+
         begin
           info.prev_result = "RUNNING"
           @mutex.synchronize { info.write! }
@@ -96,6 +98,7 @@ module Scheduler
           failed = true
         rescue => e
           Discourse.handle_job_exception(e, {message: "Running a scheduled job", job: klass})
+          error = "#{e.message}: #{e.backtrace.join("\n")}"
           failed = true
         end
         duration = ((Time.now.to_f - start) * 1000).to_i
@@ -103,10 +106,11 @@ module Scheduler
         info.prev_result = failed ? "FAILED" : "OK"
         info.current_owner = nil
         if stat
-          stat.update_columns(
+          stat.update!(
             duration_ms: duration,
             live_slots_finish: GC.stat[:heap_live_slots],
-            success: !failed
+            success: !failed,
+            error: error
           )
         end
         attempts(3) do