[receiver/libhoney] Error with unsupported Content-Encoding:

[howardyoo]

Component(s)

receiver/libhoney

What happened?

Description

when using libhoney with otel collector contrib v 0.135.0 or higher, a strange error with 'unsupported Content-Encoding:' is observed. the response ends with 400 Bad request error.

Steps to Reproduce

Setup a libhoney in the config yaml:

  libhoney:
    http:
      endpoint: 0.0.0.0:8088
      traces_url_paths:
        - "/1/events"
        - "/1/batch"
      include_metadata: true
    auth_api: https://api.honeycomb.io
    fields:
      resources:
        service_name: service_name
      scopes:
        library_name: library.name
        library_version: library.version
      attributes:
        trace_id: trace_id
        parent_id: parent_id
        span_id: span_id
        name: name
        error: error
        spankind: span.kind
        durationFields:
          - duration_ms

and use curl to submit data

curl -i -X POST \
  'http://localhost:8088/1/events/browser' \
  -H 'Content-Type: application/json' \
  -H 'X-Honeycomb-Event-Time: 0' \
  -H 'X-Honeycomb-Samplerate: 0' \
  -H 'X-Honeycomb-Team: <API_KEY>' \
  -d '[{
    "method": "GET",
    "endpoint": "/foo",
    "shard": "users",
    "duration_ms": 32
  }]'

Expected Result

HTTP/1.1 200 OK
Content-Type: application/json
Date: Tue, 04 Nov 2025 04:18:46 GMT
Content-Length: 16

[{"status":202}]

Actual Result

HTTP/1.1 400 Bad Request
Content-Type: text/plain; charset=utf-8
X-Content-Type-Options: nosniff
Date: Tue, 04 Nov 2025 04:35:42 GMT
Content-Length: 31

unsupported Content-Encoding: 

Note

• this also happens when you set the compression_algorithms: [] to the setting.
• this problem does not happen in v0.133.0 and below.

Collector version

v0.135.0

Environment information

Environment

OS: MacOS (15.6.1)

OpenTelemetry Collector configuration

libhoney:
    http:
      endpoint: 0.0.0.0:8088
      traces_url_paths:
        - "/1/events"
        - "/1/batch"
      include_metadata: true
    auth_api: https://api.honeycomb.io
    fields:
      resources:
        service_name: service_name
      scopes:
        library_name: library.name
        library_version: library.version
      attributes:
        trace_id: trace_id
        parent_id: parent_id
        span_id: span_id
        name: name
        error: error
        spankind: span.kind
        durationFields:
          - duration_ms

Log output

Additional context

HTTP/1.1 400 Bad Request
Content-Type: text/plain; charset=utf-8
X-Content-Type-Options: nosniff
Date: Tue, 04 Nov 2025 04:35:42 GMT
Content-Length: 31

unsupported Content-Encoding:

Tip

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[github-actions]

Pinging code owners:

• receiver/libhoney: @TylerHelmuth @mterhar

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[mterhar]

There were a couple of releases before 0.138.0 that had some bugs. Please upgrade to 0.139.0 or newer.

[howardyoo]

There were a couple of releases before 0.138.0 that had some bugs. Please upgrade to 0.139.0 or newer.

Just tested with collector-contrib v0.139.0. The problem, unfortunately, remains. Same symptom.

[mterhar]

I think I've fixed the issue with the PR.

$ curl -i -X POST \
  'http://localhost:8089/1/events/browser' \
  -H 'Content-Type: application/json' \
  -H 'X-Honeycomb-Event-Time: 0' \
  -H 'X-Honeycomb-Samplerate: 20' \
  -H "X-Honeycomb-Team: $HONEYCOMB_API_KEY" \
  -d '{
    "method": "GET",
    "endpoint": "/foo",
    "shard": "users",
    "duration_ms": 32
  }'

Resource attributes:
     -> service.name: Str(browser)
ScopeLogs #0
ScopeLogs SchemaURL: 
InstrumentationScope libhoney.receiver 1.0.0
LogRecord #0
ObservedTimestamp: 1970-01-01 00:00:00 +0000 UTC
Timestamp: 1754-08-30 22:43:41.128654848 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Empty()
Attributes:
     -> SampleRate: Int(20)
     -> duration_ms: Double(32)
     -> endpoint: Str(/foo)
     -> method: Str(GET)
     -> shard: Str(users)
Trace ID: 
Span ID: 
Flags: 0

And in Honeycomb, it looks like:

[howardyoo]

I think I've fixed the issue with the PR.

$ curl -i -X POST
'http://localhost:8089/1/events/browser'
-H 'Content-Type: application/json'
-H 'X-Honeycomb-Event-Time: 0'
-H 'X-Honeycomb-Samplerate: 20'
-H "X-Honeycomb-Team: $HONEYCOMB_API_KEY"
-d '{
"method": "GET",
"endpoint": "/foo",
"shard": "users",
"duration_ms": 32
}'

Resource attributes:
     -> service.name: Str(browser)
ScopeLogs #0
ScopeLogs SchemaURL: 
InstrumentationScope libhoney.receiver 1.0.0
LogRecord #0
ObservedTimestamp: 1970-01-01 00:00:00 +0000 UTC
Timestamp: 1754-08-30 22:43:41.128654848 +0000 UTC
SeverityText: 
SeverityNumber: Unspecified(0)
Body: Empty()
Attributes:
     -> SampleRate: Int(20)
     -> duration_ms: Double(32)
     -> endpoint: Str(/foo)
     -> method: Str(GET)
     -> shard: Str(users)
Trace ID: 
Span ID: 
Flags: 0

And in Honeycomb, it looks like:

Yes! I believe that is the proper behavior of it, so thank you!!!