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authorLudovic Courtès <ludo@gnu.org>2016-03-16 15:31:18 +0100
committerLudovic Courtès <ludo@gnu.org>2016-03-16 15:57:47 +0100
commit23d60ba65c137abf472a25db7317154abfc4af4d (patch)
treeaf75ddca9b5f6fccfa24d3f5b32bcf145413436b
parent1cf7e31898ba444c7c1614aa5d5680806b60442a (diff)
downloadpatches-23d60ba65c137abf472a25db7317154abfc4af4d.tar
patches-23d60ba65c137abf472a25db7317154abfc4af4d.tar.gz
substitute: Honor the 'max-age' of 'Cache-Control' headers.
This allows substitute servers to tell 'guix substitute' how long they can cache narinfo lookups. * guix/scripts/substitute.scm (cache-narinfo!): Add 'ttl' parameter. [cache-entry]: Honor it. (fetch-narinfos)[handle-narinfo-response]: Check the 'Cache-Control' header of RESPONSE and pass its 'max-age' value to 'cache-narinfo!'.
-rwxr-xr-xguix/scripts/substitute.scm23
1 files changed, 13 insertions, 10 deletions
diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 4b009d8c81..b707accff6 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -108,9 +108,8 @@ disabled!~%"))
(define %narinfo-ttl
;; Number of seconds during which cached narinfo lookups are considered
- ;; valid. This is a reasonable default value (corresponds to the TTL for
- ;; nginx's .nar cache on hydra.gnu.org) but we'd rather want publishers to
- ;; state what their TTL is in /nix-cache-info. (XXX)
+ ;; valid for substitute servers that do not advertise a TTL via the
+ ;; 'Cache-Control' response header.
(* 36 3600))
(define %narinfo-negative-ttl
@@ -471,9 +470,10 @@ for PATH."
(lambda _
(values #f #f))))
-(define (cache-narinfo! cache-url path narinfo)
- "Cache locally NARNIFO for PATH, which originates from CACHE-URL. NARINFO
-may be #f, in which case it indicates that PATH is unavailable at CACHE-URL."
+(define (cache-narinfo! cache-url path narinfo ttl)
+ "Cache locally NARNIFO for PATH, which originates from CACHE-URL, with the
+given TTL (a number of seconds or #f). NARINFO may be #f, in which case it
+indicates that PATH is unavailable at CACHE-URL."
(define now
(current-time time-monotonic))
@@ -481,7 +481,8 @@ may be #f, in which case it indicates that PATH is unavailable at CACHE-URL."
`(narinfo (version 2)
(cache-uri ,cache-uri)
(date ,(time-second now))
- (ttl ,%narinfo-ttl) ;TODO: Make this per-entry.
+ (ttl ,(or ttl
+ (if narinfo %narinfo-ttl %narinfo-negative-ttl)))
(value ,(and=> narinfo narinfo->string))))
(let ((file (narinfo-cache-file cache-url path)))
@@ -584,13 +585,15 @@ if file doesn't exist, and the narinfo otherwise."
(set! done (+ 1 done)))))
(define (handle-narinfo-response request response port result)
- (let ((len (response-content-length response)))
+ (let* ((len (response-content-length response))
+ (cache (response-cache-control response))
+ (ttl (and cache (assoc-ref cache 'max-age))))
;; Make sure to read no more than LEN bytes since subsequent bytes may
;; belong to the next response.
(case (response-code response)
((200) ; hit
(let ((narinfo (read-narinfo port url #:size len)))
- (cache-narinfo! url (narinfo-path narinfo) narinfo)
+ (cache-narinfo! url (narinfo-path narinfo) narinfo ttl)
(update-progress!)
(cons narinfo result)))
((404) ; failure
@@ -601,7 +604,7 @@ if file doesn't exist, and the narinfo otherwise."
(read-to-eof port))
(cache-narinfo! url
(find (cut string-contains <> hash-part) paths)
- #f)
+ #f ttl)
(update-progress!)
result))
(else ; transient failure