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nats-lib.lisp
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nats-lib.lisp
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(defpackage #:nats-lib
(:use #:CL #:conditions #:nats-cred)
(:export
#:connect-nats-server
#:pong
#:nats-info
#:consume-ping
#:with-nats-stream
#:err-or-ok
#:nats-msg
#:nats-subs
#:nats-pub
#:nats-unsub
))
(in-package #:nats-lib)
(eval-when (:compile-toplevel :load-toplevel :execute)
(defparameter *VERSION* (asdf:component-version (asdf:find-system :nats-cl))
"version"))
(defvar *PING* (format nil "PING~a" #\return))
(defvar *PING-REP* (format nil "PONG~a~a" #\return #\newline))
(defun connect-nats-server (url &key (port 4222) cred)
"connect to nats servers"
(declare (simple-string url)) ;;socket-connect' url must be string
(let* ((sokt (usocket:socket-connect url
port
:element-type 'character
:timeout 30
:nodelay t))
(info (nats-info (cadr (split-data (read-line (usocket:socket-stream sokt))))))
jwt nkey)
(if (gethash "nonce" info)
(progn
;; read jwt and nkey no matter server need it or not
(if cred
(multiple-value-setq (jwt nkey)
(nats-cred:read-creds-file (pathname cred)))
(error "server need authorization, but :cred path is empty"))
;; put cred path in info for client side restart
(setf (gethash "credential" info) cred)
(format (usocket:socket-stream sokt)
(nats-connect "jwt" jwt
"sig" (nats-cred:sig-nonce (gethash "nonce" info) nkey)))
;; put connect info to server
(finish-output (usocket:socket-stream sokt))
(err-or-ok (read-line (usocket:socket-stream sokt)))))
;; consume first PING
(consume-ping sokt)
;; return
(values (the usocket:usocket sokt) info)
))
(defun split-data (str)
"split data to '(protocol tails)"
(setf str (subseq str 0 (1- (length str)))) ;; clean the last #\return
(let ((first-space (position #\Space str)))
(if (not first-space)
(list str)
(list (subseq str 0 first-space)
(subseq str (1+ first-space)))))
)
;; 2020/5/2 OBSOLETE: this function used right after socket connection, answer first PING
;; and return info. Function connect-nats-server take care of this now
(defun post-connection (sokt)
"parse info and return first pong to server"
(let ((info (nats-info (cadr (split-data (read-line (usocket:socket-stream sokt))))))
)
(consume-ping sokt)
(values sokt info)))
(defun pong (sokt)
"answer the ping"
(format (usocket:socket-stream sokt) *PING-REP*)
(finish-output (usocket:socket-stream sokt))
)
;;; INFO {["option_name":option_value],...}
(defun nats-info (str)
(yason:parse str)
)
(defun consume-ping (sokt)
(let* ((stream (usocket:socket-stream sokt))
(this-line (split-data (read-line stream))))
(cond ((string= "PING" (car this-line)) (pong sokt))
(t (warn "Message ~s is not PING" this-line)))))
(defmacro with-nats-stream ((socket data &key init) &body body)
"read and handler data stream. keyword :init will eval before start to
read data from socket. @body use \"data\" become the argument binding."
(let ((stream (gensym)))
`(let ((,stream (usocket:socket-stream ,socket)))
,init
(unwind-protect
(do* ((,data (read-line ,stream) (read-line ,stream))
)
(nil)
,@body
)
(progn
(usocket:socket-close ,socket))))))
;;; +OK/ERR
(defun err-or-ok (str)
"if ok return nil, else give error. this function only use when
response mighe be ok OR err. if you know it might be err with something else.
make error directly"
(let* ((pre-ss (split-data str))
(ss (car pre-ss))
(err-msg (cadr pre-ss)))
(cond ((string= "+OK" ss)
nil)
(t (error (conditions:get-conditions err-msg)
:error-message err-msg)) ; re-write error-message for giving more details
)))
;;; MSG <subject> <sid> [reply-to] <#bytes>\r\n[payload]\r\n
(defun nats-msg (str)
"second return value used for payload"
(let (reply-to
bytes
(data (str:split-omit-nulls #\Space str)))
(if (> (length data) 3)
(setf reply-to (nth 2 data)
bytes (parse-integer (nth 3 data)))
(setf bytes (parse-integer (nth 2 data))))
(values reply-to
(make-array bytes :element-type 'character :fill-pointer 0)))
)
;;; assume sokt is empty
;;; SUB <subject> [queue group] <sid>\r\n
(defun nats-subs (sokt subject sid consume-func &key queue-group info)
(declare (usocket:usocket sokt)
(simple-string subject)
(fixnum sid))
(let ((connect-urls (if info (gethash "connect_urls" info) '())) ;; list of servers' ip
host port cred ;; these slots for restart
)
(tagbody
start
;; subscribe
(format (usocket:socket-stream sokt)
"sub ~a ~@[~a ~]~a~a~a" subject queue-group sid #\return #\newline)
;; ensure command go to server
(finish-output (usocket:socket-stream sokt))
;; ensure successful
(let ((this-line (read-line (usocket:socket-stream sokt))))
(err-or-ok this-line))
(format t "subscribe ~a successful.~%" subject)
(let (flag
reply-to
msg)
(with-nats-stream (sokt ss)
(let* ((data (split-data ss))
(head (car data))
(tail (cadr data)))
(if flag
(progn
(setf flag nil
reply-to nil)
(funcall consume-func head)) ;; consume message
;; handle message
(cond
((string= "MSG" head)
(progn (setf flag t)
(multiple-value-setq (reply-to msg) ;; msg does not used
(nats-msg tail))))
((string= "PING" head)
(pong sokt)
)
((string= "INFO" head)
;; update info and connect-urls
(setf info (nats-info tail))
(dolist (u (gethash "connect_urls" info)) (pushnew u connect-urls))
)
((string= "-ERR" head)
(restart-case
(error (conditions:get-conditions tail)
:error-message tail)
(try-to-restart ()
:report "restart this subscription by reconnect socket with stored info"
(go restart))
(restart-with-new-value (a b c)
:report "restart subscription by given data"
:interactive (lambda ()
(prompt-new-values "input the host: "
"input the port (default is 4222): "
"input the credential file path: "
))
;; set host/port/cred slot
(setf host a
port (handler-case (parse-integer b) (t () 4222))
cred c)
(go restart-with-value)
)
)
)
(t (error (conditions:get-conditions tail)
:error-message tail)))))))
restart
(if (and (not info) (not connect-urls))
(error "no binding of 'info' or connect-urls, cannot restart"))
(if info
;; set slots with info value
(setf host (concatenate 'string
(gethash "host" info)) ;; host isn't simple string
port (gethash "port" info)
cred (gethash "credential" info))
;; set with connect-nets-server
(let ((temp (str:split #\: (car connect-urls))))
(setf host (car temp)
port (cadr temp)))
)
restart-with-value
(multiple-value-setq (sokt info)
(connect-nats-server host :port port :cred cred))
(go start)))
)
(defun prompt-new-values (&rest prompts)
(loop
for mesg in prompts
do (format *query-io* mesg)
do (force-output *query-io*)
collect (read-line *query-io*) into result
finally (return result)))
;;; CONNECT {["option_name":option_value],...}
(defun nats-connect (&rest pairs)
(let ((table (make-hash-table)))
;; put init var
(loop
for (k v) in '(("verbose" nil)
("pedantic" nil)
("tls_required" nil)
("name" "")
("lang" "common-lisp")
("version" #.*VERSION*)
("protocol" 1)
("echo" t))
do (setf (gethash k table) v))
;; update with pairs
(if (not (evenp (length pairs))) (error "~a length is not even" pairs))
(do ((k (car pairs) (car pairs))
(v (cadr pairs) (cadr pairs)))
((not pairs))
(setf (gethash k table) v
pairs (cddr pairs)))
;; return str, with CONNECT at beginning
(format nil "CONNECT ~a~a~a"
(with-output-to-string (s)
(yason:encode table s))
#\return #\newline)
))
;;; PUB <subject> [reply-to] <#bytes>\r\n[payload]\r\n
(defun nats-pub (sokt subject bytes-size &optional msg &key reply-to)
(declare (usocket:usocket sokt)
(simple-string subject)
(fixnum bytes-size))
(let ((stream (usocket:socket-stream sokt)))
(format stream
"pub ~a ~@[~a ~]~a~a~a~@[~a~]~a~a"
subject reply-to bytes-size #\return #\newline
msg #\return #\newline)
(finish-output stream)
;; ensure it is successfully
(err-or-ok (read-line stream))
))
;;; UNSUB <sid> [max_msgs]
(defun nats-unsub (sokt sid &key max-msgs)
(declare (usocket:usocket sokt)
(fixnum sid))
(let ((stream (usocket:socket-stream sokt)))
(format stream
"unsub ~a~@[ ~a~]~a~a"
sid max-msgs #\return #\newline)
(finish-output stream)
;; ensure it is successfully
(err-or-ok (read-line stream))
))
;;; keep reading data from connection socket and send data to outside stream
(defun read-nats-stream (sokt &key output)
"just print out nats stream one by one"
(let ((stream (usocket:socket-stream sokt)))
(loop
do (format (if (not output)
't
output)
"~A~%"
(let ((this-line (read-line stream)))
(subseq this-line 0 (1- (length this-line))))))
))
(defun read-nats-stream-answer-ping (sokt &key output)
(let ((stream (usocket:socket-stream sokt)))
(loop
do (let ((data (read-line stream)))
(format (if (not output) 't output) "~A~%" data)
(if (string= data *PING*)
(progn
(format stream "~a" *PING-REP*)
(finish-output stream)
(format (if (not output) 't output) "~a" *PING-REP*)))
))
))