module Traces

def self.trace_context

Capture the current trace context for remote propagation.

This is a default implementation, which can be replaced by the backend.

You should prefer to use the new Traces.current_context family of methods.

def self.trace_context
	nil
end

def self.active?

Whether there is an active trace context.

This is a default implementation, which can be replaced by the backend.

def self.active?
	!!self.trace_context
end

def self.current_context

Capture the current trace context for local propagation between execution contexts.

This method returns the current trace context that can be safely passed between threads, fibers, or other execution contexts within the same process.

The returned object is opaque, in other words, you should not make assumptions about its structure.

This is a default implementation, which can be replaced by the backend.

def self.current_context
	trace_context
end

def self.with_context(context)

Execute a block within a specific trace context for local execution.

This method is designed for propagating trace context between execution contexts within the same process (threads, fibers, etc.). It temporarily switches to the specified trace context for the duration of the block execution, then restores the previous context.

When called without a block, permanently switches to the specified context. This enables manual context management for scenarios where automatic restoration isn't desired.

This is a default implementation, which can be replaced by the backend.

def self.with_context(context)
	if block_given?
		# This implementation is not ideal but the best we can do with the current interface.
		previous_context = self.trace_context
		begin
			self.trace_context = context
			yield
		ensure
			self.trace_context = previous_context
		end
	else
		self.trace_context = context
	end
end

def self.inject(headers = nil, context = nil)

Inject trace context into a headers hash for distributed propagation.

This method adds W3C Trace Context headers (traceparent, tracestate) and W3C Baggage headers to the provided headers hash, enabling distributed tracing across service boundaries. The headers hash is mutated in place.

This is a default implementation, which can be replaced by the backend.

def self.inject(headers = nil, context = nil)
	context ||= self.trace_context
	
	if context
		headers ||= Hash.new
		context.inject(headers)
	else
		headers = nil
	end
	
	return headers
end

def self.extract(headers)

Extract trace context from headers for distributed propagation.

The returned object is opaque, in other words, you should not make assumptions about its structure.

This is a default implementation, which can be replaced by the backend.

def self.extract(headers)
	Context.extract(headers)
end

def self.enabled?

def self.enabled?
	Backend.const_defined?(:Interface)
end

def self.Provider(klass, &block)

Extend the specified class in order to emit traces.

def self.Provider(klass, &block)
	klass.extend(Singleton)
	provider = klass.traces_provider
	klass.prepend(provider)
	
	provider.module_exec(&block) if block_given?
	
	return provider
end