M doc/guix.texi => doc/guix.texi +83 -2
@@ 4177,10 4177,91 @@ tool suite.)
the ``message of the day''.
@end deffn
-@deffn {Monadic Procedure} nscd-service [#:glibc glibc]
-Return a service that runs libc's name service cache daemon (nscd).
+@cindex name service cache daemon
+@cindex nscd
+@deffn {Monadic Procedure} nscd-service [@var{config}] [#:glibc glibc]
+Return a service that runs libc's name service cache daemon (nscd) with the
+given @var{config}---an @code{<nscd-configuration>} object.
@end deffn
+@defvr {Scheme Variable} %nscd-default-configuration
+This is the default @code{<nscd-configuration>} value (see below) used
+by @code{nscd-service}. This uses the caches defined by
+@var{%nscd-default-caches}; see below.
+@end defvr
+
+@deftp {Data Type} nscd-configuration
+This is the type representing the name service cache daemon (nscd)
+configuration.
+
+@table @asis
+
+@item @code{log-file} (default: @code{"/var/log/nscd.log"})
+Name of nscd's log file. This is where debugging output goes when
+@code{debug-level} is strictly positive.
+
+@item @code{debug-level} (default: @code{0})
+Integer denoting the debugging levels. Higher numbers mean more
+debugging output is logged.
+
+@item @code{caches} (default: @var{%nscd-default-caches})
+List of @code{<nscd-cache>} objects denoting things to be cached; see
+below.
+
+@end table
+@end deftp
+
+@deftp {Data Type} nscd-cache
+Data type representing a cache database of nscd and its parameters.
+
+@table @asis
+
+@item @code{database}
+This is a symbol representing the name of the database to be cached.
+Valid values are @code{passwd}, @code{group}, @code{hosts}, and
+@code{services}, which designate the corresponding NSS database
+(@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
+
+@item @code{positive-time-to-live}
+@itemx @code{negative-time-to-live} (default: @code{20})
+A number representing the number of seconds during which a positive or
+negative lookup result remains in cache.
+
+@item @code{check-files?} (default: @code{#t})
+Whether to check for updates of the files corresponding to
+@var{database}.
+
+For instance, when @var{database} is @code{hosts}, setting this flag
+instructs nscd to check for updates in @file{/etc/hosts} and to take
+them into account.
+
+@item @code{persistent?} (default: @code{#t})
+Whether the cache should be stored persistently on disk.
+
+@item @code{shared?} (default: @code{#t})
+Whether the cache should be shared among users.
+
+@item @code{max-database-size} (default: 32@tie{}MiB)
+Maximum size in bytes of the database cache.
+
+@c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
+@c settings, so leave them out.
+
+@end table
+@end deftp
+
+@defvr {Scheme Variable} %nscd-default-caches
+List of @code{<nscd-cache>} objects used by default by
+@code{nscd-configuration} (see above.)
+
+It enables persistent and aggressive caching of service and host name
+lookups. The latter provides better host name lookup performance,
+resilience in the face of unreliable name servers, and also better
+privacy---often the result of host name lookups is in local cache, so
+external name servers do not even need to be queried.
+@end defvr
+
+
@deffn {Monadic Procedure} syslog-service
Return a service that runs @code{syslogd} with reasonable default
settings.
M gnu/services/base.scm => gnu/services/base.scm +117 -4
@@ 33,8 33,10 @@
#:select (mount-flags->bit-mask))
#:use-module (guix gexp)
#:use-module (guix monads)
+ #:use-module (guix records)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
+ #:use-module (ice-9 match)
#:use-module (ice-9 format)
#:export (root-file-system-service
file-system-service
@@ 46,6 48,16 @@
console-font-service
udev-service
mingetty-service
+
+ %nscd-default-caches
+ %nscd-default-configuration
+
+ nscd-configuration
+ nscd-configuration?
+
+ nscd-cache
+ nscd-cache?
+
nscd-service
syslog-service
guix-service
@@ 374,9 386,110 @@ the ``message of the day''."
#:allow-empty-passwords? allow-empty-passwords?
#:motd motd)))))))
-(define* (nscd-service #:key (glibc (canonical-package glibc)))
- "Return a service that runs libc's name service cache daemon (nscd)."
- (with-monad %store-monad
+(define-record-type* <nscd-configuration> nscd-configuration
+ make-nscd-configuration
+ nscd-configuration?
+ (log-file nscd-configuration-log-file ;string
+ (default "/var/log/nscd.log"))
+ (debug-level nscd-debug-level ;integer
+ (default 0))
+ ;; TODO: See nscd.conf in glibc for other options to add.
+ (caches nscd-configuration-caches ;list of <nscd-cache>
+ (default %nscd-default-caches)))
+
+(define-record-type* <nscd-cache> nscd-cache make-nscd-cache
+ nscd-cache?
+ (database nscd-cache-database) ;symbol
+ (positive-time-to-live nscd-cache-positive-time-to-live) ;integer
+ (negative-time-to-live nscd-cache-negative-time-to-live
+ (default 20)) ;integer
+ (suggested-size nscd-cache-suggested-size ;integer ("default module
+ ;of hash table")
+ (default 211))
+ (check-files? nscd-cache-check-files? ;Boolean
+ (default #t))
+ (persistent? nscd-cache-persistent? ;Boolean
+ (default #t))
+ (shared? nscd-cache-shared? ;Boolean
+ (default #t))
+ (max-database-size nscd-cache-max-database-size ;integer
+ (default (* 32 (expt 2 20))))
+ (auto-propagate? nscd-cache-auto-propagate? ;Boolean
+ (default #t)))
+
+(define %nscd-default-caches
+ ;; Caches that we want to enable by default. Note that when providing an
+ ;; empty nscd.conf, all caches are disabled.
+ (list (nscd-cache (database 'hosts)
+
+ ;; Aggressively cache the host name cache to improve
+ ;; privacy and resilience.
+ (positive-time-to-live (* 3600 12))
+ (negative-time-to-live 20)
+ (persistent? #t))
+
+ (nscd-cache (database 'services)
+
+ ;; Services are unlikely to change, so we can be even more
+ ;; aggressive.
+ (positive-time-to-live (* 3600 24))
+ (negative-time-to-live 3600)
+ (check-files? #t) ;check /etc/services changes
+ (persistent? #t))))
+
+(define %nscd-default-configuration
+ ;; Default nscd configuration.
+ (nscd-configuration))
+
+(define (nscd.conf-file config)
+ "Return the @file{nscd.conf} configuration file for @var{config}, an
+@code{<nscd-configuration>} object."
+ (define cache->config
+ (match-lambda
+ (($ <nscd-cache> (= symbol->string database)
+ positive-ttl negative-ttl size check-files?
+ persistent? shared? max-size propagate?)
+ (string-append "\nenable-cache\t" database "\tyes\n"
+
+ "positive-time-to-live\t" database "\t"
+ (number->string positive-ttl) "\n"
+ "negative-time-to-live\t" database "\t"
+ (number->string negative-ttl) "\n"
+ "suggested-size\t" database "\t"
+ (number->string size) "\n"
+ "check-files\t" database "\t"
+ (if check-files? "yes\n" "no\n")
+ "persistent\t" database "\t"
+ (if persistent? "yes\n" "no\n")
+ "shared\t" database "\t"
+ (if shared? "yes\n" "no\n")
+ "max-db-size\t" database "\t"
+ (number->string max-size) "\n"
+ "auto-propagate\t" database "\t"
+ (if propagate? "yes\n" "no\n")))))
+
+ (match config
+ (($ <nscd-configuration> log-file debug-level caches)
+ (text-file "nscd.conf"
+ (string-append "\
+# Configuration of libc's name service cache daemon (nscd).\n\n"
+ (if log-file
+ (string-append "logfile\t" log-file)
+ "")
+ "\n"
+ (if debug-level
+ (string-append "debug-level\t"
+ (number->string debug-level))
+ "")
+ "\n"
+ (string-concatenate
+ (map cache->config caches)))))))
+
+(define* (nscd-service #:optional (config %nscd-default-configuration)
+ #:key (glibc (canonical-package glibc)))
+ "Return a service that runs libc's name service cache daemon (nscd) with the
+given @var{config}---an @code{<nscd-configuration>} object."
+ (mlet %store-monad ((nscd.conf (nscd.conf-file config)))
(return (service
(documentation "Run libc's name service cache daemon (nscd).")
(provision '(nscd))
@@ 388,7 501,7 @@ the ``message of the day''."
(start #~(make-forkexec-constructor
(list (string-append #$glibc "/sbin/nscd")
- "-f" "/dev/null" "--foreground")))
+ "-f" #$nscd.conf "--foreground")))
(stop #~(make-kill-destructor))
(respawn? #f)))))