Transports: DRY HTTP Transport & Client classes

[p-datadog]

What does this PR do?

Removes duplicated code from Transport classes and deletes most of the HTTP::Client classes.

This PR continues on the path started in #5095.

Most of the HTTP::Client classes were functionally identical, except for the Tracing::Traces one which had additional logic for API version downgrades. The difference between the Client classes was in send_XXX_payload methods which were largely identical. They have been replaced by a single send_request method with the XXX as the argument. Then, all of the HTTP::Client classes have been removed except for the Tracing::Traces one which derives from the core HTTP::Client.

This PR moves also moves the downgrading methods to the core class because they will be used by DI in the next PR. Accordingly, some unit tests have been moved to core. Not all because I think there needs to be additional work to have mock APIs, since existing unit tests under Tracing::Traces utilize the APIs in Traces.

Finally, a base Transport class in core has been created with the API management code that was identical across all of the Transport classes in the various components. The per-component Transport classes remain since they still have unique methods but these now all derive from the core base class.

Motivation:
Making transport layer more legible to implement API downgrades for DI

Change log entry
None

Additional Notes:

How to test the change?

Existing tests

[github-actions]

Thank you for updating Change log entry section 👏

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[github-actions]

Typing analysis

Note: Ignored files are excluded from the next sections.

steep:ignore comments

This PR clears 2 steep:ignore comments.

steep:ignore comments (+0-2)

✅ Cleared:

lib/datadog/core/telemetry/transport/http/telemetry.rb:19
lib/datadog/data_streams/transport/http/client.rb:14

Untyped methods

This PR introduces 7 untyped methods and 2 partially typed methods, and clears 7 untyped methods and 2 partially typed methods.

Untyped methods (+7-7)

❌ Introduced:

sig/datadog/core/transport/transport.rbs:9
└── def initialize: (untyped version) -> void
sig/datadog/core/transport/transport.rbs:18
└── def initialize: (untyped version) -> void
sig/datadog/core/transport/transport.rbs:44
└── def initialize: (untyped apis, untyped default_api, logger: untyped) -> void
sig/datadog/core/transport/transport.rbs:46
└── def current_api: () -> untyped
sig/datadog/core/transport/transport.rbs:50
└── def set_api!: (untyped api_id) -> untyped
sig/datadog/core/transport/transport.rbs:54
└── def downgrade!: () -> untyped
sig/datadog/tracing/transport/traces.rbs:53
└── def stats: () -> untyped

✅ Cleared:

sig/datadog/tracing/transport/traces.rbs:71
└── def initialize: (untyped apis, untyped default_api, ?logger: untyped) -> void
sig/datadog/tracing/transport/traces.rbs:75
└── def stats: () -> untyped
sig/datadog/tracing/transport/traces.rbs:77
└── def current_api: () -> untyped
sig/datadog/tracing/transport/traces.rbs:83
└── def downgrade!: () -> untyped
sig/datadog/tracing/transport/traces.rbs:85
└── def change_api!: (untyped api_id) -> untyped
sig/datadog/tracing/transport/traces.rbs:92
└── def initialize: (untyped version) -> void
sig/datadog/tracing/transport/traces.rbs:101
└── def initialize: (untyped version) -> void

Partially typed methods (+2-2)

❌ Introduced:

sig/datadog/core/transport/transport.rbs:52
└── def downgrade?: (untyped response) -> (false | untyped)
sig/datadog/tracing/transport/traces.rbs:51
└── def send_traces: (Array[Tracing::TraceOperation] traces) -> untyped

✅ Cleared:

sig/datadog/tracing/transport/traces.rbs:73
└── def send_traces: (Array[Tracing::TraceOperation] traces) -> untyped
sig/datadog/tracing/transport/traces.rbs:81
└── def downgrade?: (untyped response) -> (false | untyped)

Untyped other declarations

This PR introduces 15 untyped other declarations, and clears 14 untyped other declarations. It decreases the percentage of typed other declarations from 69.16% to 69.11% (-0.05%).

Untyped other declarations (+15-14)

❌ Introduced:

sig/datadog/core/transport/transport.rbs:5
└── @version: untyped
sig/datadog/core/transport/transport.rbs:7
└── attr_reader version: untyped
sig/datadog/core/transport/transport.rbs:14
└── @version: untyped
sig/datadog/core/transport/transport.rbs:16
└── attr_reader version: untyped
sig/datadog/core/transport/transport.rbs:23
└── @apis: untyped
sig/datadog/core/transport/transport.rbs:25
└── @default_api: untyped
sig/datadog/core/transport/transport.rbs:27
└── @logger: untyped
sig/datadog/core/transport/transport.rbs:29
└── @current_api_id: untyped
sig/datadog/core/transport/transport.rbs:31
└── @client: untyped
sig/datadog/core/transport/transport.rbs:33
└── attr_reader client: untyped
sig/datadog/core/transport/transport.rbs:35
└── attr_reader apis: untyped
sig/datadog/core/transport/transport.rbs:37
└── attr_reader default_api: untyped
sig/datadog/core/transport/transport.rbs:39
└── attr_reader current_api_id: untyped
sig/datadog/core/transport/transport.rbs:41
└── attr_reader logger: untyped
sig/datadog/core/transport/transport.rbs:42
└── attr_accessor self.http_client_class: untyped

✅ Cleared:

sig/datadog/tracing/transport/traces.rbs:49
└── @apis: untyped
sig/datadog/tracing/transport/traces.rbs:51
└── @default_api: untyped
sig/datadog/tracing/transport/traces.rbs:53
└── @logger: untyped
sig/datadog/tracing/transport/traces.rbs:55
└── @current_api_id: untyped
sig/datadog/tracing/transport/traces.rbs:57
└── @client: untyped
sig/datadog/tracing/transport/traces.rbs:61
└── attr_reader client: untyped
sig/datadog/tracing/transport/traces.rbs:63
└── attr_reader apis: untyped
sig/datadog/tracing/transport/traces.rbs:65
└── attr_reader default_api: untyped
sig/datadog/tracing/transport/traces.rbs:67
└── attr_reader current_api_id: untyped
sig/datadog/tracing/transport/traces.rbs:69
└── attr_reader logger: untyped
sig/datadog/tracing/transport/traces.rbs:88
└── @version: untyped
sig/datadog/tracing/transport/traces.rbs:90
└── attr_reader version: untyped
sig/datadog/tracing/transport/traces.rbs:97
└── @version: untyped
sig/datadog/tracing/transport/traces.rbs:99
└── attr_reader version: untyped

If you believe a method or an attribute is rightfully untyped or partially typed, you can add # untyped:accept to the end of the line to remove it from the stats.

[datadog-datadog-prod-us1]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage
• Patch Coverage: 98.25%
• Total Coverage: 95.22% (+0.06%)

View detailed report

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 20fab87 | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-12-03 20:38:20

Comparing candidate commit c87e32b in PR branch dry-transport with baseline commit 48fa3f2 in branch master.

Found 2 performance improvements and 1 performance regressions! Performance is the same for 41 metrics, 2 unstable metrics.

scenario:profiling - Allocations (profiling disabled)

• 🟩 throughput [+275753.174op/s; +282543.999op/s] or [+5.702%; +5.843%]

scenario:profiling - Allocations (profiling enabled)

• 🟩 throughput [+269961.246op/s; +278054.255op/s] or [+5.625%; +5.794%]

scenario:profiling - intern mixed existing and new

• 🟥 throughput [-2.850op/s; -1.722op/s] or [-9.131%; -5.517%]

[ivoanjo]

Thanks for picking this up! Left a few notes.

TBH I suspect in the long run it may be easier to start from scratch and rebuilding the support for the required feature-set VS slowly untangling the current mess back into a good design step by step.

But having said that, I'll take any improvement I can get.

[vpellan]

LGTM (except send_request_impl in tests stuff)

[ivoanjo]

While ideally there's a few more cleanups I'd like to get in, me and @p-datadog spoke about it and I think this PR as-is is already an improvement, so leaving my 👍

[p-datadog]

I will be addressing the comments in the future PRs, thank you for the feedback.