out_datadog: custom added ability ot set custom HTTP headers

[AndrewChubatiuk]

Added ability to set custom HTTP headers for Datadog output

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

• [x] Example configuration file for the change

[INPUT]
    name              tail
    path              /var/lib/docker/containers/**/*.log
    path_key          path
    multiline.parser  docker, cri
    Parser            docker
    Docker_Mode       On

[SERVICE]
    Flush        1
    Parsers_File parsers.conf

[Output]
    name                  datadog
    match                 *
    host                  victorialogs
    port                  9428
    tls                   off
    compress              gzip
    apikey                test
    dd_service            test
    dd_source             data
    dd_message_key        log
    dd_tags               env:dev
    header                VL-Stream-Fields env

• [N/A] Debug log output from testing the change

• [N/A] Attached Valgrind output that shows no leaks or memory corruption was found

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• [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

• [x] Documentation required for this feature

https://github.com/fluent/fluent-bit-docs/pull/1467

Backporting

• [x] Backport to latest stable release.

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[edsiper]

@AndrewChubatiuk thanks for this contribution.

Quick question, what is the use case where you need to set custom HTTP headers when sending data to datadog ?

[AndrewChubatiuk]

hey @edsiper it's needed on setups with a custom endpoint, where custom headers are used for extra authentification, multitenancy, routing, etc.