bug(node-trace-sdk): could not load plugin errors are polutting stdout

[vmarchaud]

Since the express module is in the list of default plugins, the plugin loader try to load it when started:

PluginLoader#load: could not load plugin @opentelemetry/plugin-express of module express. Error: Cannot find module '@opentelemetry/plugin-express'
Require stack:
- /home/node/node_modules/@opentelemetry/node/build/src/instrumentation/PluginLoader.js
- /home/node/node_modules/@opentelemetry/node/build/src/NodeTracerProvider.js
- /home/node/node_modules/@opentelemetry/node/build/src/index.js
- /home/node/node_modules/@rlvt/telemetry/build/index.js
- /home/node/src/index.js

However in my case i don't want the express plugin, and i also don't want to those errors because it's expected.

I would don't think we should log if the module isn't found in this case, WDYT ?

[dyladan]

Can you just add { express: { enabled: false } } to the plugin config?

[vmarchaud]

Yeah i can do it as a workaround, however i don't think we should require users to disable plugins they don't want (since they didn't install them in the first place).

[vmarchaud]

I think we should really fix this, its really common for people to think the sdk is not working when seeing those logs. Could we just log those as debug ? cc @open-telemetry/javascript-approvers

[naseemkullah]

FWIW I do find them useful to know which plugin I forgot to install. But it does not merit Error level as @vmarchaud mentioned. Warn, Info or Debug are all more appropriate than Error.

[naseemkullah]

It's probably more Warn worthy for non default plugins that are explicitly enabled but not found, but implementing that check for explicitly enabled might be more logic than its worth. Let's just choose A lower level for 'em all.

[vmarchaud]

Yeah my main issue is that when a default plugin is added, i need to add an entry in the tracing sdk to ignore this plugin specially. There is currently 13 default plugins, so by default if someone just want to use the http one, there will be 12 error logs at startup.

It's probably more Warn worthy for non default plugins that are explicitly enabled but not found

That would have been the best solution but since the config are merged there no way at the plugin loader level to know if the plugin was explicitly enabled or not :/

[obecny]

FYI I'm refactoring default plugin instrumentation (started by @dyladan ) once this is done this might go away as the approach for plugin will be different. If this is not urgent you might think of delaying that until then.

[vmarchaud]

That's fine for me, waiting for your PR then

[vmarchaud]

Closing since it will be fixed with the instrumentation class