build(deps): use OpenTelemetry for tracing

[mhilton]

Update tracing to use OpenTelemetry instead of the, no longer supported, jaeger and opentracing. This introduces a backwards incompatible change to the flux command, which no longer supports the --trace=jaeger flag. Jaeger now recommends using the OpenTelemtry API.

Checklist

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[Copilot]

Pull request overview

This PR migrates the Flux codebase from the deprecated OpenTracing/Jaeger libraries to OpenTelemetry for distributed tracing. The migration introduces a breaking change by removing support for the --trace=jaeger flag in favor of --trace=otlp, with a deprecation warning for users still using the old flag. The change updates all tracing instrumentation across the codebase to use OpenTelemetry APIs while maintaining the same tracing functionality.

Key Changes

• Replaced OpenTracing/Jaeger dependencies with OpenTelemetry packages (otel, otel/trace, otel/sdk)
• Updated tracing API calls throughout the codebase: span.Finish() → span.End(), span.SetTag() → span.SetAttributes(), etc.
• Modified the flux CLI to use OTLP exporter with environment-based configuration instead of Jaeger-specific setup

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
stdlib/universe/parallel.go	Migrated PartitionMergeTransformation span creation and lifecycle to OpenTelemetry
stdlib/influxdata/influxdb/to.go	Updated toTransformation tracing to use OpenTelemetry APIs
stdlib/http/requests/requests.go	Converted HTTP request tracing to OpenTelemetry with proper attribute setting
stdlib/http/post.go	Updated HTTP POST tracing to use OpenTelemetry span methods
stdlib/experimental/iox/source.go	Migrated IOx SQL source tracing and error recording to OpenTelemetry
stdlib/experimental/http/http_experimental.go	Updated experimental HTTP GET tracing to OpenTelemetry
repl/repl.go	Migrated REPL input tracing to OpenTelemetry (with context handling issues)
lang/query.go	Updated query span type reference to OpenTelemetry
lang/compiler_test.go	Replaced mocktracer with OpenTelemetry in-memory test exporter for tracing tests
lang/compiler.go	Migrated plan and execution span creation to OpenTelemetry throughout compilation pipeline
internal/spec/build.go	Updated spec building tracing to use OpenTelemetry APIs
internal/jaeger/jaeger_test.go	Completely rewrote tests to use OpenTelemetry span contexts instead of Jaeger mocks
internal/jaeger/jaeger.go	Reimplemented InfoFromSpan to extract trace info from OpenTelemetry spans
execute/transport.go	Updated consecutiveTransport tracing to use OpenTelemetry span lifecycle
execute/executor.go	Migrated executor source tracing to OpenTelemetry
cmd/flux/main.go	Replaced Jaeger tracer initialization with OTLP exporter and TracerProvider configuration
go.mod	Added OpenTelemetry dependencies, removed Jaeger/OpenTracing dependencies, updated related packages
go.sum	Updated checksums for all modified and new dependencies

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[Copilot]

There's a version mismatch in OpenTelemetry packages: otel and otel/trace are at v1.38.0, while otel/sdk is at v1.37.0 and otel/exporters/otlp/otlptrace/otlptracegrpc is at v1.34.0. While these packages are designed to be compatible across minor versions, it's generally better practice to align the versions where possible to avoid potential compatibility issues.

Consider updating all OpenTelemetry packages to use the same minor version (e.g., all v1.38.x) if available, or document why different versions are required.

Suggested change

	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.34.0
	go.opentelemetry.io/otel/sdk v1.37.0
	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.38.0
	go.opentelemetry.io/otel/sdk v1.38.0

[Copilot]

The semantic convention package version (v1.4.0) is significantly outdated. OpenTelemetry semantic conventions have evolved considerably since v1.4.0, and the latest versions provide more comprehensive and standardized attributes.

Consider updating to a more recent version of semantic conventions (e.g., semconv/v1.20.0 or later) to ensure compatibility with modern OpenTelemetry tools and to benefit from improved standardization. The ServiceNameKey attribute used at line 103 is available in all versions, so this should be a straightforward update.

Suggested change

	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
	semconv "go.opentelemetry.io/otel/semconv/v1.20.0"

[Copilot]

Pull request overview

Copilot reviewed 20 out of 21 changed files in this pull request and generated no new comments.

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[mhilton]

This has a lot of implications downstream, so I'm putting it down for now. I intend to revisit in the future.