Unable to export traces/spans from my Ruby on Rails application

[anandhasudhan]

I'm trying to export traces from my Ruby on Rails application to Coralogix using an OTEL collector but I am receiving OpenTelemetry errors during traces export. It turns out that the traces are not being sent to the OTEL collector but not sure what is wrong here.

Below is my opentelemetry.rb configuration:

require 'opentelemetry/sdk'
require 'opentelemetry/instrumentation/all'
require 'opentelemetry-exporter-otlp'

OpenTelemetry::SDK.configure do |c|
  c.service_name = 'basic-web'
  c.use_all

  c.add_span_processor(
    OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new(
      OpenTelemetry::Exporter::OTLP::Exporter.new(
        endpoint: 'http://0.0.0.0:4318' 
      )
    )
  )
end

I installed the OTEL collector following the guides linked below:

• https://opentelemetry.io/docs/collector/installation/,
• https://coralogix.com/docs/opentelemetry-using-docker/

OTEL collector `config.yaml`

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
  filelog:
    start_at: beginning
    include:
      - /example.log
    include_file_path: true
    multiline: {line_start_pattern: "\\n"}

processors:
  batch:
        
exporters:
  coralogix:
    domain: "coralogix.us"
    private_key: "<private-key>"
    application_name: "basic-uat4"
    subsystem_name: "basic-web"
    timeout: 30s
  debug: {}

service:
  pipelines:
    logs:
      receivers: [ filelog ]
      processors: [batch]
      exporters: [ debug,coralogix ]
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [ debug,coralogix ]

I keep getting the following errors in my RoR application and don't have additional debug information to pin down the root cause:

E, [2024-03-07T11:50:52.524292 #72268] ERROR -- : OpenTelemetry error: Unable to export 8 spans

Version info

ruby - 2.6.10p210
rails - 4.2.11.3
Gem versions

opentelemetry-api | 1.1.0
opentelemetry-sdk | 1.1.0
opentelemetry-common | 0.19.7
opentelemetry-instrumentation-all | 0.33.0
opentelemetry-exporter-otlp (0.23.0)

Could you please help me understand what is wrong with my opentelemetry.rb/otel collector configuration?

[anandhasudhan]

For additional context, port 4318 is exposed from my OTEL Collector docker container. When I navigate to http://0.0.0.0:4318/, I receive a 404 page not found message.

[anandhasudhan]

I was able to resolve this by appending /v1/traces to the endpoint.