feat: Relayer tracing

[DeshErBojhaa]

Description

💀 Similar Files

docs/tracing.md and docs/logging.md slightly overlap. Since both tracing and logging sometimes share similar characteristics and their responsibilities are also close, we need to decide whether and how to merge these two files.

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closes: IBC-145

🔴 Please read

• The purpose of this PR is to introduce tracing while avoiding code modification (as much as possible).
• Not implemented fine-grained tracing for the sake of keeping the implementation unchanged. The pros of having fine-grained tracing do not outweigh making changes to the code.
• The only exception is the start function, which requires extensive tracing.

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Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Linked to GitHub issue with discussion and accepted design, OR link to spec that describes this work.
• Wrote unit and integration tests.
• Added relevant natspec and godoc comments.
• Provide a conventional commit message to follow the repository standards.
• Re-reviewed Files changed in the GitHub PR explorer.
• Review SonarCloud Report in the comment section below once CI passes.

[linear]

IBC-145 Implement logging best-practices in the relayer

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.86%. Comparing base (2bf3eec) to head (de96759).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #681   +/-   ##
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  Coverage   99.86%   99.86%           
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  Files          17       17           
  Lines         767      767           
=======================================
  Hits          766      766           
  Misses          1        1           

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[Copilot]

Pull Request Overview

This PR introduces distributed tracing capabilities to the relayer while minimizing code modifications. The implementation adds OpenTelemetry support with OTLP export alongside traditional stdout logging, moving tracing configuration from the server config to a dedicated tracing configuration section.

• Adds new tracing module with OpenTelemetry OTLP support and configurable logging
• Updates tracing attributes across relayer modules to include error debugging information
• Migrates log level configuration from server config to dedicated tracing config section

Reviewed Changes

Copilot reviewed 22 out of 25 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
programs/relayer/src/tracing.rs	New tracing configuration module with OpenTelemetry OTLP support
programs/relayer/config.example.json	Updates configuration format to use dedicated tracing section
packages/relayer/core/src/config.rs	Moves tracing config from server config to dedicated TracingConfig struct
packages/relayer/core/src/builder.rs	Enhances instrumentation in relayer startup and request handling
Multiple module files	Updates tracing attributes to include error debugging across relayer modules

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[gjermundgaraba]

This task was only for the relayer and should target main. You can split out the attestor tracing and put that into a separate PR when this has been merged to main and then backported to feat/ibc-attestor. I will only review the relayer part now.

Edit: I see now that there are only minor changes to the attestor part, which is good. But please target main for this.

[gjermundgaraba]

This is a good start, left a few comments, but I also wonder about issue (IBC-145): it states a couple of definitions of done that I am not sure is fulfilled here. Please make sure that it is.

[Copilot]

Pull Request Overview

This PR adds distributed tracing capability to the IBC Eureka relayer to improve observability and debugging in distributed systems. The implementation leverages OpenTelemetry standards for trace collection and propagation across service boundaries.

• Introduces observability configuration with optional OTLP export for distributed tracing
• Adds automatic trace context propagation for gRPC services using interceptors
• Includes local Grafana stack setup for development and testing

Reviewed Changes

Copilot reviewed 34 out of 38 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
programs/relayer/src/observability.rs	Core observability module with OTLP tracer/logger setup
packages/relayer/lib/src/utils/tracing_layer.rs	gRPC interceptor for automatic trace context extraction
packages/relayer/core/src/builder.rs	Integration of tracing interceptor with gRPC server
packages/relayer/core/src/config.rs	Configuration structure for observability settings
scripts/local-grafana-stack/	Complete local observability stack with Grafana, Tempo, and Prometheus
Various module files	Enhanced tracing attributes for better error context

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[Copilot]

The comment indicates there's no shutdown method in 0.30, but using let _ = provider; makes the intent unclear. Consider using drop(provider); to explicitly show intentional disposal or add a more descriptive comment explaining why the variable is being discarded.

Suggested change

	let _ = provider;
	drop(provider);

[Copilot]

These explicit drop() calls in tests are unnecessary since variables would be dropped automatically at the end of their scope. Consider removing them for cleaner test code.

Suggested change

drop(provider);

[Copilot]

These explicit drop() calls in tests are unnecessary since variables would be dropped automatically at the end of their scope. Consider removing them for cleaner test code.

Suggested change

drop(tracer_provider);