Merge pull request #61 from alphagov/msw/xrayperiments

Check for XRAY_PATCH_AWS_SDK env var, and do not patch aws_sdk if unset
alphagov · Oct 4, 2018 · 77a4018 · 77a4018
2 parents 55211b1 + 76a5bd9
commit 77a4018
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,6 @@
+* Only instrument the `aws_sdk` gem with AWS X-Ray if the
+  `XRAY_PATCH_AWS_SDK` environment variable is present.
+
 # 1.9.3
 
 * Do not report Sidekiq queue thresholds in healthchecks which are

diff --git a/lib/govuk_app_config/govuk_xray.rb b/lib/govuk_app_config/govuk_xray.rb
@@ -8,9 +8,10 @@ def self.initialize(app)
   end
 
   def self.start
-    # if aws-sdk is loaded, we want to instrument that too
-    patch = Gem.loaded_specs.has_key?('aws-sdk-core') ?
-              %I[aws_sdk net_http] : %I[net_http]
+    # patching 'aws_sdk' seem to impose a large memory overhead, so
+    # don't do that by default
+    patch = ENV.has_key?('XRAY_PATCH_AWS_SDK') ?
+               %I[aws_sdk net_http] : %I[net_http]
 
     # if there isn't a name set, attempting to record a segment will
     # throw an error