[exporter/datadog]: fix service name resolution #570

ericmustin · 2021-07-08T19:22:31Z

Description

This PR fixes the service_name resolution for the datadog exporter. The order of operations here is:

Resource attribute service.name
User supplied datadog service

However, in practice due to the work done in this PR: open-telemetry/opentelemetry-python#1480

The resource attribute resolution will provide a default resource service.name of "unknown_service" in the event no resource attribute has been set for service.name. This means that even when a user does supply a fallback datadog service it will never be discovered beacuse the default "unknown_service" will take precedence. This PR updates the datadog exporter to explicitly check if a default unknown_service is being used for resource attribute service.name and if it does, allows the datadog supplied service to override it.

Fixes # (issue)

Internall bug reports impacting end users

Type of change

Please delete options that are not relevant.

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Test A

Does This PR Require a Core Repo Change?

Yes. - Link to PR:
No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

Followed the style guidelines of this project
Changelogs have been updated
Unit tests have been added
Documentation has been updated

NathanielRN

Minor suggestions, otherwise looks good to me 😄

NathanielRN · 2021-07-08T22:01:08Z

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/exporter.py

@@ -312,19 +313,23 @@ def _parse_tags_str(tags_str):
    return parsed_tags


-def _extract_tags_from_resource(resource):
+def _extract_tags_from_resource(resource, fallback_service_name):
    """Parse tags from resource.attributes, except service.name which
    has special significance within datadog"""
    tags = {}
    service_name = None


Since it's not used below on line 321 anymore, I think it would make sense to push the initialization of service_name = None lower to line 322 perhaps?

makes sense, updated!

NathanielRN · 2021-07-08T22:05:23Z

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/exporter.py


    for attribute_key, attribute_value in resource.attributes.items():
        if attribute_key == SERVICE_NAME_TAG:
            service_name = attribute_value
        else:
            tags[attribute_key] = attribute_value
+
+    if service_name is None or service_name == UNKNOWN_SERVICE_NAME:


It look like UNKNOWN_SERVICE_NAME is only used 1 time in this exporter? Because that's the case you could consider just doing "unknown_service" like we do in opentelemetry-sdk:

https://github.com/open-telemetry/opentelemetry-python/blob/f11ed2f3bacb11d53a7a2b4837cf6308fa34cc71/opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py#L172

But not a blocker!

Either that or change both to use UNKNOWN_SERVICE_NAME

thanks, updated, i just removed the use of UNKNOWN_SERVICE_NAME entirely and went with "unknown_service".

NathanielRN · 2021-07-08T22:12:43Z

CHANGELOG.md

@@ -28,6 +28,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  ([#560](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/560))
 - `opentelemetry-instrumentation-django` Migrated Django middleware to new-style.
  ([#533](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/533))
+- `opentelemetry-exporter-datadog` Fix service name resolution.


Maybe this describes the change more explicitly?

Suggested change

- `opentelemetry-exporter-datadog` Fix service name resolution.

- `opentelemetry-exporter-datadog` Datadog exporter should not use `unknown_service` as fallback resource service name

lgtm, updated

CHANGELOG.md

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/constants.py

lzchen · 2021-07-09T02:12:09Z

Both jaeger and zipkin do not allow users to set the service_name through the constructor. Should we be consistent and recommend users to set the service_name through a Resource?

ericmustin · 2021-07-09T05:52:30Z

@lzchen yes generally speaking I think that's a good direction to take, as I'd like to nudge folks to use the opentelemetry semantic conventions when using opentelemetry libraries. If that means removing the service argument for this exporter that's fine with me.

My only blocker is that I would have to coordinate with an update to the docs/blog posts/etc on my employers doc website so that any onboarding users were using the correct code snippets. So, if possible, i would prefer if we could just ship this non-breaking change (all the feedback seems reasonable, will update), and then I can try to get everything in order to update the exporter to be in line with other non-otlp exporters. If you'd like to make an issue for that work and assign it to me so that we can make sure this is tracked/completed, that's good with me.

Is that approach ok for y'all?

lzchen · 2021-07-09T15:35:06Z

@ericmustin
Sure that sounds good. Please add a TODO to that section to indicate that we plan on changing to using the Resource.
I've created an issue here. Please comment on it so I can assign you.

NathanielRN · 2021-07-09T23:22:11Z

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/exporter.py

    if not (resource and getattr(resource, "attributes", None)):
-        return [tags, service_name]
+        return [tags, fallback_service_name]


Technically tags could just be {} here since it's not really use here at this point too! But that's not in scope for your PR I would say :-)

good catch. As you can tell my code is not particularly pythonic (i'm mostly ruby these days 😅 ). But there's a lot in this little exporter that could get cleaned up. I'll make a note to also try to give this code another pass for #574

lzchen

Could you add a test for this?

ericmustin · 2021-07-18T19:50:06Z

@lzchen sorry for delay was on pto, added a test lmk if anything else needed here

[exporter/datadog]: fix service name resolution

a61c752

ericmustin requested review from a team, owais and aabmass and removed request for a team July 8, 2021 19:22

ericmustin added 6 commits July 8, 2021 15:24

[exporter/datadog]: update changelog

f094c60

[exporter/datadog]: update changelog again

12ef531

[exporter/datadog]: fix logic

e45662e

[exporter/datadog]: fix logic again

2156de4

[exporter/datadog]: linting hooray

e341d67

[exporter/datadog]: more linting hooray

2829dd7

NathanielRN approved these changes Jul 8, 2021

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lzchen reviewed Jul 9, 2021

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lzchen reviewed Jul 9, 2021

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exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/constants.py Outdated Show resolved Hide resolved

lzchen mentioned this pull request Jul 9, 2021

Datadog exporter to use service_name from Resource #574

Closed

ericmustin added 2 commits July 9, 2021 19:13

[exporter/datadog]: add feedback from code review

0da9fe0

[exporter/datadog]: merge upstream

1cc8fbd

ericmustin requested review from NathanielRN and lzchen July 9, 2021 23:20

NathanielRN approved these changes Jul 9, 2021

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lzchen approved these changes Jul 12, 2021

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ericmustin added 4 commits July 18, 2021 22:03

[exporter/datadog]: add service name fallback test

ad5aecd

[exporter/datadog]: add service name fallback test, fix tests

9a96ef3

[exporter/datadog]: resolve conflicts

74d7cd3

[exporter/datadog]: linting

995e59d

Merge branch 'main' into datadog_fix_env_var

b41cb25

Merge branch 'main' into datadog_fix_env_var

9d99049

lzchen merged commit f6ffa76 into open-telemetry:main Jul 20, 2021

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[exporter/datadog]: fix service name resolution #570

[exporter/datadog]: fix service name resolution #570

ericmustin commented Jul 8, 2021

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ericmustin commented Jul 18, 2021

	- `opentelemetry-exporter-datadog` Fix service name resolution.
	- `opentelemetry-exporter-datadog` Datadog exporter should not use `unknown_service` as fallback resource service name

[exporter/datadog]: fix service name resolution #570

[exporter/datadog]: fix service name resolution #570

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ericmustin commented Jul 8, 2021

Description

Type of change

How Has This Been Tested?

Does This PR Require a Core Repo Change?

Checklist:

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lzchen commented Jul 9, 2021

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