out_datadog: added support for site configuration field

[lucastemb]

Add site Parameter to Fluent Bit Plugin for Regional Data Routing

Enter [N/A] in the box, if an item is not applicable to your change.

Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change
• Debug log output from testing the change

• Attached Valgrind output that shows no leaks or memory corruption was found

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• [ N/A ] Documentation required for this feature

Backporting

• [N/A] Backport to latest stable release.

---

Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[lucastemb]

Example Config File:

[SERVICE]
    Flush        1
    Log_Level    trace
    Parsers_File parsers.conf

[INPUT]
    Name        dummy
    Tag         dummy
    Dummy       {"message": "Testing support for site confiruation ", "test": "AGNTLOG-206", "container_id": "abc123def456", "container_name": "/ecs-web-service", "container_image": "nginx:1.24-alpine", "ecs_cluster": "arn:aws:ecs:us-west-2:123456789012:cluster/production-cluster", "ecs_task_definition": "web-service:42", "ecs_task_arn": "arn:aws:ecs:us-west-2:123456789012:task/production-cluster/abc123def456-7890-1234-5678-901234567890"}

[OUTPUT]
    Name        datadog
    Match       *
    apikey      ${DD_API_KEY}
    dd_hostname foobar
    provider    ecs
    dd_source   fluent-bit
    dd_service  test-service
    dd_tags     env:test,version:1.0
    compress    gzip 
    site        us3.datadoghq.com```

[lucastemb]

Valgrind Output:

==1318749== 
==1318749== HEAP SUMMARY:
==1318749==     in use at exit: 0 bytes in 0 blocks
==1318749==   total heap usage: 10,659 allocs, 10,659 frees, 27,179,822 bytes allocated
==1318749== 
==1318749== All heap blocks were freed -- no leaks are possible
==1318749== 
==1318749== For lists of detected and suppressed errors, rerun with: -s
==1318749== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

[lucastemb]

Debug Log Output:

[2025/07/11 18:38:45] [ info] Configuration:
[2025/07/11 18:38:45] [ info]  flush time     | 1.000000 seconds
[2025/07/11 18:38:45] [ info]  grace          | 5 seconds
[2025/07/11 18:38:45] [ info]  daemon         | 0
[2025/07/11 18:38:45] [ info] ___________
[2025/07/11 18:38:45] [ info]  inputs:
[2025/07/11 18:38:45] [ info]      dummy
[2025/07/11 18:38:45] [ info] ___________
[2025/07/11 18:38:45] [ info]  filters:
[2025/07/11 18:38:45] [ info] ___________
[2025/07/11 18:38:45] [ info]  outputs:
[2025/07/11 18:38:45] [ info]      datadog.0
[2025/07/11 18:38:45] [ info] ___________
[2025/07/11 18:38:45] [ info]  collectors:
[2025/07/11 18:38:45] [ info] [fluent bit] version=4.0.5, commit=9def01d7de, pid=1326162
[2025/07/11 18:38:45] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2025/07/11 18:38:45] [ info] [storage] ver=1.5.3, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2025/07/11 18:38:45] [ info] [simd    ] disabled
[2025/07/11 18:38:45] [ info] [cmetrics] version=1.0.4
[2025/07/11 18:38:45] [ info] [ctraces ] version=0.6.6
[2025/07/11 18:38:45] [ info] [input:dummy:dummy.0] initializing
[2025/07/11 18:38:45] [ info] [input:dummy:dummy.0] storage_strategy='memory' (memory only)
[2025/07/11 18:38:45] [debug] [dummy:dummy.0] created event channels: read=28 write=29
[2025/07/11 18:38:45] [debug] [datadog:datadog.0] created event channels: read=30 write=31
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] scheme: http://
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] site parameter set to: us3.datadoghq.com
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] uri: /api/v2/logs
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] using site for host construction: us3.datadoghq.com
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] created base hostname: http-intake.logs.
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] about to concatenate site: us3.datadoghq.com (length: 17)
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] after concatenation: http-intake.logs.us3.datadoghq.com
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] host constructed from site: http-intake.logs.us3.datadoghq.com
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] port: 80
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] json_date_key: timestamp
[2025/07/11 18:38:45] [debug] [output:datadog:datadog.0] compress_gzip: 1
[2025/07/11 18:38:45] [ info] [sp] stream processor started
[2025/07/11 18:38:45] [ info] [engine] Shutdown Grace Period=5, Shutdown Input Grace Period=2
[2025/07/11 18:38:45] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:45] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:46] [trace] [input chunk] update output instances with new chunk size diff=403, records=1, input=dummy.0
[2025/07/11 18:38:46] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:46] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:46] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:46] [trace] [sched] 0 timer coroutines destroyed
[2025/07/11 18:38:47] [trace] [task 0x5e9f010] created (id=0)
[2025/07/11 18:38:47] [debug] [task] created task=0x5e9f010 id=0 OK
[2025/07/11 18:38:47] [trace] [input chunk] update output instances with new chunk size diff=403, records=1, input=dummy.0
[2025/07/11 18:38:47] [trace] [upstream] get new connection for http-intake.logs.us3.datadoghq.com:80, net setup:
net.connect_timeout        = 10 seconds
net.source_address         = any
net.keepalive              = enabled
net.keepalive_idle_timeout = 30 seconds
net.max_worker_connections = 0
[2025/07/11 18:38:47] [trace] [net] connection #38 in process to http-intake.logs.us3.datadoghq.com:80