Module: Arcp::Lease::Subsetting

Defined in:
lib/arcp/lease.rb

Class Method Summary collapse

Class Method Details

.bound(parent:, request:, parent_remaining: nil) ⇒ Object

Compute a delegate lease bounded by the parent. Raises ‘LeaseSubsetViolation` if requested capabilities exceed parent, requested expires_at is beyond parent, or remaining budget can’t cover the requested amount.



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# File 'lib/arcp/lease.rb', line 157

def bound(parent:, request:, parent_remaining: nil)
  excess = request.capabilities - parent.capabilities
  unless excess.empty?
    raise Arcp::Errors::LeaseSubsetViolation,
          "child lease capabilities not in parent: #{excess.inspect}"
  end

  if request.expires_at && parent.expires_at
    parent_t = Time.iso8601(parent.expires_at)
    req_t = Time.iso8601(request.expires_at)
    if req_t > parent_t
      raise Arcp::Errors::LeaseSubsetViolation,
            "child expires_at #{request.expires_at} exceeds parent #{parent.expires_at}"
    end
  end

  budget = nil
  if request.budget
    parent_pc = parent_remaining || (parent.budget&.per_currency || {})
    missing = request.budget.per_currency.filter_map do |ccy, amt|
      available = parent_pc[ccy] || BigDecimal('0')
      (ccy if amt > available)
    end
    unless missing.empty?
      raise Arcp::Errors::LeaseSubsetViolation,
            "child budget exceeds parent remaining for: #{missing.inspect}"
    end

    budget = request.budget
  end

  model_use = bound_model_use(parent: parent, request: request)

  Lease.new(
    id: Arcp::Ids.session_id.sub(/^ses_/, 'lse_'),
    capabilities: request.capabilities,
    budget: budget,
    model_use: model_use,
    expires_at: request.expires_at || parent.expires_at,
    issued_at: Time.now.utc.iso8601
  )
end

.bound_model_use(parent:, request:) ⇒ Object 



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# File 'lib/arcp/lease.rb', line 200

def bound_model_use(parent:, request:)
  return nil unless request.model_use

  unless request.model_use.all? { |pattern| Arcp::ModelPattern.implied_by?(parent.model_use, pattern) }
    raise Arcp::Errors::LeaseSubsetViolation,
          "child model.use expands beyond parent: #{request.model_use.inspect}"
  end

  request.model_use
end