Class: Async::Utilization::Schema

Inherits:
Object
  • Object
show all
Defined in:
lib/async/utilization/schema.rb

Overview

Defines a schema for shared memory serialization.

The schema defines the layout and types for serializing utilization metrics to shared memory. It’s only needed when using Observer for shared memory storage - the Registry itself doesn’t require a schema.

Examples:

Assign a schema to an observer:

schema = Async::Utilization::Schema.build(
	total_requests: :u64,
	active_requests: :u32,
)

registry = Async::Utilization::Registry.new
observer = Async::Utilization::Observer.open(schema, "/path/to/shm", 4096, 0)
registry.observer = observer

Defined Under Namespace

Classes: Field

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fields) ⇒ Schema

Initialize a new schema.



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# File 'lib/async/utilization/schema.rb', line 49

def initialize(fields)
	@fields = fields.freeze
	
	# Build an offsets cache mapping field names to Field objects for fast lookup
	@offsets = {}
	@fields.each do |field|
		@offsets[field.name] = field
	end
	@offsets.freeze
end

Instance Attribute Details

#fields ⇒ Object (readonly)

Returns the value of attribute fields.



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# File 'lib/async/utilization/schema.rb', line 61

def fields
  @fields
end

#The fields in this schema.(fields) ⇒ Object (readonly) 



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# File 'lib/async/utilization/schema.rb', line 61

attr :fields

Class Method Details

.build(fields) ⇒ Object

Build a schema from raw fields.

Factory method that takes a hash of field names to types and creates Field instances with calculated offsets.



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# File 'lib/async/utilization/schema.rb', line 34

def self.build(fields)
	field_instances = []
	offset = 0
	
	fields.each do |key, type|
		field_instances << Field.new(name: key.to_sym, type: type, offset: offset)
		offset += IO::Buffer.size_of(type)
	end
	
	new(field_instances)
end

Instance Method Details

#[](field) ⇒ Object

Get field information for a given field.



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# File 'lib/async/utilization/schema.rb', line 67

def [](field)
	@offsets[field.to_sym]
end

#to_a ⇒ Object

Convert schema to array format for shared memory.



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# File 'lib/async/utilization/schema.rb', line 74

def to_a
	@fields.map do |field|
		[field.name, field.type, field.offset]
	end
end