Add user agent to HTTP client

[leonardehrenfried]

Summary

On one of my deployments we also use Entur's Lamassu with ~70 GBFS feeds. OTP's regular GBFS downloading was
leading another developer looking after Lamassu to think that a load test was underway. 😳

For this reason I'm setting a user agent identifying HTTP calls that originate from OTP.

cc @derhuerst @hbruch

[leonardehrenfried]

@t2gran The architecture test fails because of a dependency on org.opentripplanner.model.projectinfo. May I allow this dependency?

[leonardehrenfried]

I just checked and the current user agent is "Apache-HttpClient/5.3.1 (Java/21.0.2)".

With almost all updaters you can configure the HTTP headers and if you set User-Agent then your customised version will be used rather than the default.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.76%. Comparing base (6fc4f60) to head (6c956b8).

Additional details and impacted files

@@            Coverage Diff             @@
##             dev-2.x    #5724   +/-   ##
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  Coverage      67.76%   67.76%           
  Complexity     16471    16471           
==========================================
  Files           1901     1901           
  Lines          72113    72114    +1     
  Branches        7430     7430           
==========================================
+ Hits           48868    48869    +1     
  Misses         20734    20734           
  Partials        2511     2511           

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[optionsome]

Btw is it possible to define custom user agent through updater configuration after this?

[leonardehrenfried]

Yes, you can set the User-Agent header and it overrides the one I'm setting in this PR. That also works before this PR.

[derhuerst]

I strongly suggest nudging users to define their own User-Agent(s) – as this is a best practice when querying (potentially third-party) APIs automatically –, e.g. by adding an example configuration to the docs or even printing a warning if no custom User-Agent is configured.

[t2gran]

@derhuerst I agree that it is a is a best practice for a C2B service, but in this case it is a B2B call, OTP call the RT-Services. In most cases just using "OpenTripPlanner" should be sufficient. I would also recommend having an aggregator service between OTP and the RT-Services - especially if there are many OTP instances. The aggregator should maintain a clean consistent set of updates and remove old updates. It minimize the calls to the RT-Services and keep the latency between the aggregator and OTP down, while removing some of the load from the OTP instances. The aggregator and OTP should be in the same data senter or same cluster.

[t2gran]

The architecture test fails because of a dependency on org.opentripplanner.model.projectinfo. May I allow this dependency?

For the record, this was discussed in the dev meeting. Dependencies from the framework code to the domain model is not allowed. The solution in this case was to drop the version number from the token. Another alternative is to pass inn the client-name as parameter when the HTTP Client is created.