syndicate-2017/racket/syndicate/drivers/config.rkt

39 lines
1.2 KiB
Racket

#lang syndicate
;; Monitor configuration files.
(provide (struct-out config)
spawn-configuration
define/query-config
config-ref)
(define-logger syndicate/drivers/config)
(require racket/file)
(require/activate syndicate/drivers/filesystem)
;; (config Any Any)
(struct config (scope item) #:prefab)
(define (spawn-configuration scope path #:hook [hook void])
(spawn #:name (list 'configuration-monitor scope path)
(hook)
(during (file-content path file->list $items)
(cond
[(not items)
(log-syndicate/drivers/config-warning "config ~s is missing" path)]
[else
(log-syndicate/drivers/config-info "loading config ~s" path)
(for [(item items)]
(log-syndicate/drivers/config-info "config ~s: ~s" path item)
(assert (config scope item)))]))))
(define-syntax define/query-config
(syntax-rules ()
[(_ scope id default)
(define/query-config id scope id default)]
[(_ id scope key default)
(define/query-value id default (config scope (list 'key $val)) val)]))
(define (config-ref #:scope [scope ?] key default)
(immediate-query (query-value default (config scope (list key $val)) val)))