spec: use sharding for DJ apm spec

FIXES APM-25
flag = none

also properly implments plugin
reset so that we can enable/disable
without rebooting the process

test plan:
  specs pass flaky spec catcher
Change-Id: I96e8137e351639559d68c8f1e9242e1c315cb26d
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/231006
Reviewed-by: David Warkentin <[email protected]>
Reviewed-by: James Butters <[email protected]>
Tested-by: Service Cloud Jenkins <[email protected]>
QA-Review: Ethan Vizitei <[email protected]>
Product-Review: Ethan Vizitei <[email protected]>

lib/canvas/apm/inst_jobs/plugin.rb

@@ -36,6 +36,7 @@ class << self
           attr_writer :tracer
 
           def reset!
+            super
             @tracer = nil
           end
 

spec/lib/canvas/apm/inst_jobs/plugin_spec.rb

@@ -15,7 +15,8 @@
 # You should have received a copy of the GNU Affero General Public License along
 # with this program. If not, see <http://www.gnu.org/licenses/>.
 #
-require 'spec_helper'
+require_relative '../../../../sharding_spec_helper'
+
 require 'delayed/testing'
 require_dependency "canvas/apm/inst_jobs/plugin"
 
@@ -75,6 +76,7 @@ def enabled
   end
 
   describe 'instrumented job invocation' do
+    specs_require_sharding
     let(:sample_job_object) do
       stub_const('SampleJob', Class.new do
         def perform; end
@@ -84,15 +86,18 @@ def perform; end
     it 'has resource name equal to job name' do
       expect(Canvas::Apm::InstJobs::Plugin.tracer).to eq(tracer)
       job = Delayed::Job.enqueue(sample_job_object.new, {})
+      job.account_id = 12345
       Delayed::Testing.run_job(job)
       expect(span.resource).to eq('SampleJob')
       expect(span.tags["inst_jobs.id"] > 0).to be_truthy
       expect(span.tags["inst_jobs.queue"]).to eq("canvas_queue")
       expect(span.tags["inst_jobs.priority"] > 0).to be_truthy
       expect(span.tags["inst_jobs.attempts"]).to eq(0)
       expect(span.tags["inst_jobs.strand"]).to be_nil
-      expect(span.tags["shard"]).to eq(job.shard_id)
-      expect(span.tags["root_account"]).to eq(job.account_id)
+      expect(job.shard_id > 0).to be_truthy
+      expect(span.tags["shard"]).to eq(job.shard_id.to_s)
+      expect(job.account_id > 0).to be_truthy
+      expect(span.tags["root_account"]).to eq(job.account_id.to_s)
     end
   end
 end

spec/lib/canvas/apm_spec.rb

@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU Affero General Public License along
 # with this program. If not, see <http://www.gnu.org/licenses/>.
 
-require 'spec_helper'
+require_relative '../../sharding_spec_helper'
 
 describe Canvas::Apm do
   after(:each) do