nixo
/
guix-devel
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

offload: Move macro definitions before use. 

* guix/scripts/offload.scm (lock-file, unlock-file, with-file-lock,
  with-machine-lock, machine-slot-file, acquire-build-slot,
  release-build-slot): Move definitions above their first use.
This commit is contained in:
Ludovic Courtès 2014-03-09 18:08:21 +01:00
parent 2a51db7d8d
commit 59f704dff6
1 changed files with 85 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

154
guix/scripts/offload.scm
View File

@ -174,6 +174,86 @@ determined."
%lshg-command (strerror (system-error-errno args)))
#f)))
;;;
;;; Synchronization.
;;;
(define (lock-file file)
"Wait and acquire an exclusive lock on FILE. Return an open port."
(mkdir-p (dirname file))
(let ((port (open-file file "w0")))
(fcntl-flock port 'write-lock)
port))
(define (unlock-file lock)
"Unlock LOCK."
(fcntl-flock lock 'unlock)
(close-port lock)
#t)
(define-syntax-rule (with-file-lock file exp ...)
"Wait to acquire a lock on FILE and evaluate EXP in that context."
(let ((port (lock-file file)))
(dynamic-wind
(lambda ()
#t)
(lambda ()
exp ...)
(lambda ()
(unlock-file port)))))
(define-syntax-rule (with-machine-lock machine hint exp ...)
"Wait to acquire MACHINE's exclusive lock for HINT, and evaluate EXP in that
context."
(with-file-lock (machine-lock-file machine hint)
exp ...))
(define (machine-slot-file machine slot)
"Return the file name of MACHINE's file for SLOT."
;; For each machine we have a bunch of files representing each build slot.
;; When choosing a build machine, we attempt to get an exclusive lock on one
;; of these; if we fail, that means all the build slots are already taken.
;; Inspired by Nix's build-remote.pl.
(string-append (string-append %state-directory "/offload/"
(build-machine-name machine)
"/" (number->string slot))))
(define (acquire-build-slot machine)
"Attempt to acquire a build slot on MACHINE. Return the port representing
the slot, or #f if none is available.
This mechanism allows us to set a hard limit on the number of simultaneous
connections allowed to MACHINE."
(mkdir-p (dirname (machine-slot-file machine 0)))
(with-machine-lock machine 'slots
(any (lambda (slot)
(let ((port (open-file (machine-slot-file machine slot)
"w0")))
(catch 'flock-error
(lambda ()
(fcntl-flock port 'write-lock #:wait? #f)
;; Got it!
(format (current-error-port)
"process ~a acquired build slot '~a'~%"
(getpid) (port-filename port))
port)
(lambda args
;; PORT is already locked by another process.
(close-port port)
#f))))
(iota (build-machine-parallel-builds machine)))))
(define (release-build-slot slot)
"Release SLOT, a build slot as returned as by 'acquire-build-slot'."
(close-port slot))
;;;
;;; Offloading.
;;;
(define* (offload drv machine
#:key print-build-trace? (max-silent-time 3600)
(build-timeout 7200) (log-port (current-output-port)))
@ -299,6 +379,11 @@ success, #f otherwise."
(zero? (close-pipe pipe)))))))
;;;
;;; Scheduling.
;;;
(define (machine-matches? machine requirements)
"Return #t if MACHINE matches REQUIREMENTS."
(and (string=? (build-requirements-system requirements)
@ -350,75 +435,6 @@ allowed on MACHINE."
"Return the name of the file used as a lock when choosing a build machine."
(string-append %state-directory "/offload/machine-choice.lock"))
(define (lock-file file)
"Wait and acquire an exclusive lock on FILE. Return an open port."
(mkdir-p (dirname file))
(let ((port (open-file file "w0")))
(fcntl-flock port 'write-lock)
port))
(define (unlock-file lock)
"Unlock LOCK."
(fcntl-flock lock 'unlock)
(close-port lock)
#t)
(define-syntax-rule (with-file-lock file exp ...)
"Wait to acquire a lock on FILE and evaluate EXP in that context."
(let ((port (lock-file file)))
(dynamic-wind
(lambda ()
#t)
(lambda ()
exp ...)
(lambda ()
(unlock-file port)))))
(define-syntax-rule (with-machine-lock machine hint exp ...)
"Wait to acquire MACHINE's exclusive lock for HINT, and evaluate EXP in that
context."
(with-file-lock (machine-lock-file machine hint)
exp ...))
(define (machine-slot-file machine slot)
"Return the file name of MACHINE's file for SLOT."
;; For each machine we have a bunch of files representing each build slot.
;; When choosing a build machine, we attempt to get an exclusive lock on one
;; of these; if we fail, that means all the build slots are already taken.
;; Inspired by Nix's build-remote.pl.
(string-append (string-append %state-directory "/offload/"
(build-machine-name machine)
"/" (number->string slot))))
(define (acquire-build-slot machine)
"Attempt to acquire a build slot on MACHINE. Return the port representing
the slot, or #f if none is available.
This mechanism allows us to set a hard limit on the number of simultaneous
connections allowed to MACHINE."
(mkdir-p (dirname (machine-slot-file machine 0)))
(with-machine-lock machine 'slots
(any (lambda (slot)
(let ((port (open-file (machine-slot-file machine slot)
"w0")))
(catch 'flock-error
(lambda ()
(fcntl-flock port 'write-lock #:wait? #f)
;; Got it!
(format (current-error-port)
"process ~a acquired build slot '~a'~%"
(getpid) (port-filename port))
port)
(lambda args
;; PORT is already locked by another process.
(close-port port)
#f))))
(iota (build-machine-parallel-builds machine)))))
(define (release-build-slot slot)
"Release SLOT, a build slot as returned as by 'acquire-build-slot'."
(close-port slot))
(define %slots
;; List of acquired build slots (open ports).