Set Sinatra resource setting at beginning of request and delay setting fallback resource #1628
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As of #1623, the profiler records the `resource` of the root span, on top of the span id and trace id during sampling. Also, as discusssed in the description of #1623 (in the "Getting the correct `resource`" section) integrations where the `resource` is only set at the end pose an extra challenge, as the request may not be finished in time for the `resource` to be included in the profiler payload. This means that the profiler may miss the `resource` for some of the requests, depending on timing of when the sampling happens and when the request finishes. (Note that in this case, the trace id and span id will still be propagated, so the samples will always be able to be tied back to the trace that originated them; it's just the `resource` that will not be included in the profiler data). To avoid this issue for many of our customers, let's set the Sinatra `resource` setting to the beginning of the request, thus avoiding the issue altogether for Sinatra. Note that I did not touch the existing code to set the resource at the end, which had a quite scary TODO (lines 47-64) and seemed like something I shouldn't touch. Note 2: This is similar to what we did in #1626 for the Rails integration.
By using a `nil` resource, the profiler can tell that no resource is yet available, and thus will not gather/display the fallback resource.
marcotc
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Aug 3, 2021
| else | ||
| Sinatra::Env.datadog_span(env, self.class) | ||
| end | ||
| if sinatra_request_span # DEV: Is it possible for sinatra_request_span to ever be nil here? |
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Unlikely, but something we can track with self-telemetry in the future to build confidence. (no action now)
marcotc
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Aug 3, 2021
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As of #1623, the profiler records the `resource` of the root span, on top of the span id and trace id during sampling. Also, as discusssed in the description of #1623 (in the "Getting the correct `resource`" section) integrations where the `resource` is only set at the end pose an extra challenge, as the request may not be finished in time for the `resource` to be included in the profiler payload. This means that the profiler may miss the `resource` for some of the requests, depending on timing of when the sampling happens and when the request finishes. (Note that in this case, the trace id and span id will still be propagated, so the samples will always be able to be tied back to the trace that originated them; it's just the `resource` that will not be included in the profiler data). To avoid this issue for many of our customers, let's move the Grape `resource` setting to the beginning of the request, thus avoiding the issue altogether for this integration. (Note: This is similar to what we did for Rails in #1626 and Sinatra in #1628)
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As of #1623, the profiler records the `resource` of the root span, on top of the span id and trace id during sampling. Also, as discusssed in the description of #1623 (in the "Getting the correct `resource`" section) integrations where the `resource` is only set at the end pose an extra challenge, as the request may not be finished in time for the `resource` to be included in the profiler payload. This means that the profiler may miss the `resource` for some of the requests, depending on timing of when the sampling happens and when the request finishes. (Note that in this case, the trace id and span id will still be propagated, so the samples will always be able to be tied back to the trace that originated them; it's just the `resource` that will not be included in the profiler data). To avoid this issue for many of our customers, let's move the Grape `resource` setting to the beginning of the request, thus avoiding the issue altogether for this integration. (Note: This is similar to what we did for Rails in #1626 and Sinatra in #1628)
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…ssing This fixes a regression introduced in version 0.52.0 by #1628. When a Sinatra modular application being traced is missing the `Datadog::Contrib::Sinatra::Tracer` middleware (as documented in <https://docs.datadoghq.com/tracing/setup_overview/setup/ruby/#sinatra>), no Sinatra request span is ever created (only a route span). Because we didn't properly account for this in `#datadog_span`, the following `NoMethodError` was triggered: ``` NoMethodError: undefined method `[]' for nil:NilClass dd-trace-rb/lib/ddtrace/contrib/sinatra/env.rb:13:in `datadog_span' dd-trace-rb/lib/ddtrace/contrib/sinatra/tracer.rb:122:in `block in route_eval' dd-trace-rb/lib/ddtrace/tracer.rb:283:in `trace' dd-trace-rb/lib/ddtrace/contrib/sinatra/tracer.rb:105:in `route_eval' ruby-2.7.4/gems/sinatra-2.1.0/lib/sinatra/base.rb:1013:in `block (2 levels) in route!' ``` I suspect this is the same issue as was reported in #1643. Because this configuration is actually not desirable -- spans reported will be missing crucial request information, as discussed in #1643 -- I've also added a warning to hopefully steer users in the right direction.
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As of #1623, the profiler records the
resourceof the root span, on top of the span id and trace id during sampling.Also, as discusssed in the description of #1623 (in the "Getting the correct
resource" section) integrations where theresourceis only set at the end pose an extra challenge, as the request may not be finished in time for theresourceto be included in the profiler payload.This means that the profiler may miss the
resourcefor some of the requests, depending on timing of when the sampling happens and when the request finishes.(Note that in this case, the trace id and span id will still be propagated, so the samples will always be able to be tied back to the trace that originated them; it's just the
resourcethat will not be included in the profiler data).To avoid this issue for many of our customers, let's set the Sinatra
resourcesetting at the beginning of the request, thus avoiding the issue altogether for Sinatra.Note: I did not touch the existing code to set the resource at the end, which had a quite scary TODO (lines 47-64) and seemed like something I shouldn't touch.
Note 2: This is similar to what we did in #1626 for the Rails integration.
Finally, I also tweaked
TracerMiddlewareto only set the fallback resource (the request method) at the end of the request (if needed at all), instead keeping aniluntil theresourcegets resolved. This way, the profiler can tell that no resource isyet available, and thus will not gather/display the fallback resource.