diff options
| -rw-r--r-- | .dir-locals.el | 1 | ||||
| -rw-r--r-- | doc/guix.texi | 73 | ||||
| -rw-r--r-- | emacs/guix-devel.el | 2 | ||||
| -rw-r--r-- | gnu/services.scm | 42 | ||||
| -rw-r--r-- | gnu/services/base.scm | 2 |
5 files changed, 114 insertions, 6 deletions
diff --git a/.dir-locals.el b/.dir-locals.el index 54d5bdaefc..0873c1d747 100644 --- a/.dir-locals.el +++ b/.dir-locals.el @@ -23,6 +23,7 @@ (eval . (put 'lambda* 'scheme-indent-function 1)) (eval . (put 'substitute* 'scheme-indent-function 1)) (eval . (put 'modify-phases 'scheme-indent-function 1)) + (eval . (put 'modify-services 'scheme-indent-function 1)) (eval . (put 'with-directory-excursion 'scheme-indent-function 1)) (eval . (put 'package 'scheme-indent-function 0)) (eval . (put 'origin 'scheme-indent-function 0)) diff --git a/doc/guix.texi b/doc/guix.texi index 0a3827911b..01e28041f2 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -5363,16 +5363,40 @@ The @code{services} field lists @dfn{system services} to be made available when the system starts (@pxref{Services}). The @code{operating-system} declaration above specifies that, in addition to the basic services, we want the @command{lshd} secure shell -daemon listening on port 2222, and allowing remote @code{root} logins -(@pxref{Invoking lshd,,, lsh, GNU lsh Manual}). Under the hood, +daemon listening on port 2222 (@pxref{Networking Services, +@code{lsh-service}}). Under the hood, @code{lsh-service} arranges so that @code{lshd} is started with the right command-line options, possibly with supporting configuration files -generated as needed (@pxref{Defining Services}). @xref{operating-system -Reference}, for details about the available @code{operating-system} -fields. +generated as needed (@pxref{Defining Services}). + +@cindex customization, of services +@findex modify-services +Occasionally, instead of using the base services as is, you will want to +customize them. For instance, to change the configuration of +@code{guix-daemon} and Mingetty (the console log-in), you may write the +following instead of @var{%base-services}: + +@lisp +(modify-services %base-services + (guix-service-type config => + (guix-configuration + (inherit config) + (use-substitutes? #f) + (extra-options '("--gc-keep-outputs")))) + (mingetty-service-type config => + (mingetty-configuration + (inherit config) + (motd (plain-file "motd" "Hi there!"))))) +@end lisp + +@noindent +The effect here is to change the options passed to @command{guix-daemon} +when it is started, as well as the ``message of the day'' that appears +when logging in at the console. @xref{Service Reference, +@code{modify-services}}, for more on that. The configuration for a typical ``desktop'' usage, with the X11 display -server, a desktop environment, network management, an SSH server, and +server, a desktop environment, network management, power management, and more, would look like this: @lisp @@ -5382,6 +5406,8 @@ more, would look like this: @xref{Desktop Services}, for the exact list of services provided by @var{%desktop-services}. @xref{X.509 Certificates}, for background information about the @code{nss-certs} package that is used here. +@xref{operating-system Reference}, for details about all the available +@code{operating-system} fields. Assuming the above snippet is stored in the @file{my-system-config.scm} file, the @command{guix system reconfigure my-system-config.scm} command @@ -7539,6 +7565,41 @@ Here is an example of how a service is created and manipulated: @result{} #t @end example +The @code{modify-services} form provides a handy way to change the +parameters of some of the services of a list such as +@var{%base-services} (@pxref{Base Services, @code{%base-services}}). Of +course, you could always use standard list combinators such as +@code{map} and @code{fold} to do that (@pxref{SRFI-1, List Library,, +guile, GNU Guile Reference Manual}); @code{modify-services} simply +provides a more concise form for this common pattern. + +@deffn {Scheme Syntax} modify-services @var{services} @ + (@var{type} @var{variable} => @var{body}) @dots{} + +Modify the services listed in @var{services} according to the given +clauses. Each clause has the form: + +@example +(@var{type} @var{variable} => @var{body}) +@end example + +where @var{type} is a service type, such as @var{guix-service-type}, and +@var{variable} is an identifier that is bound within @var{body} to the +value of the service of that @var{type}. @xref{Using the Configuration +System}, for an example. + +This is a shorthand for: + +@example +(map (lambda (service) @dots{}) @var{services}) +@end example +@end deffn + +Next comes the programming interface for service types. This is +something you want to know when writing new service definitions, but not +necessarily when simply looking for ways to customize your +@code{operating-system} declaration. + @deftp {Data Type} service-type @cindex service type This is the representation of a @dfn{service type} (@pxref{Service Types diff --git a/emacs/guix-devel.el b/emacs/guix-devel.el index 170ce1ad54..8eb030942c 100644 --- a/emacs/guix-devel.el +++ b/emacs/guix-devel.el @@ -198,6 +198,7 @@ to find 'modify-phases' keywords." "mbegin" "mlet" "mlet*" + "modify-services" "munless" "mwhen" "run-with-state" @@ -288,6 +289,7 @@ Each rule should have a form (SYMBOL VALUE). See `put' for details." (mlet 2) (mlet* 2) (modify-phases 1) + (modify-services 1) (munless 1) (mwhen 1) (operating-system 0) diff --git a/gnu/services.scm b/gnu/services.scm index d0fe0ade17..818252386f 100644 --- a/gnu/services.scm +++ b/gnu/services.scm @@ -48,6 +48,7 @@ service-kind service-parameters + modify-services service-back-edges fold-services @@ -133,6 +134,47 @@ (parameters service-parameters)) +(define-syntax %modify-service + (syntax-rules (=>) + ((_ service) + service) + ((_ svc (kind param => exp ...) clauses ...) + (if (eq? (service-kind svc) kind) + (let ((param (service-parameters svc))) + (service (service-kind svc) + (begin exp ...))) + (%modify-service svc clauses ...))))) + +(define-syntax modify-services + (syntax-rules () + "Modify the services listed in SERVICES according to CLAUSES. Each clause +must have the form: + + (TYPE VARIABLE => BODY) + +where TYPE is a service type, such as 'guix-service-type', and VARIABLE is an +identifier that is bound within BODY to the value of the service of that +TYPE. Consider this example: + + (modify-services %base-services + (guix-service-type config => + (guix-configuration + (inherit config) + (use-substitutes? #f) + (extra-options '(\"--gc-keep-derivations\")))) + (mingetty-service-type config => + (mingetty-configuration + (inherit config) + (motd (plain-file \"motd\" \"Hi there!\"))))) + +It changes the configuration of the GUIX-SERVICE-TYPE instance, and that of +all the MINGETTY-SERVICE-TYPE instances. + +This is a shorthand for (map (lambda (svc) ...) %base-services)." + ((_ services clauses ...) + (map (lambda (service) + (%modify-service service clauses ...)) + services)))) ;;; diff --git a/gnu/services/base.scm b/gnu/services/base.scm index 618cef8a98..b8e8ccd5f1 100644 --- a/gnu/services/base.scm +++ b/gnu/services/base.scm @@ -57,6 +57,7 @@ mingetty-configuration mingetty-configuration? mingetty-service + mingetty-service-type %nscd-default-caches %nscd-default-configuration @@ -74,6 +75,7 @@ guix-configuration guix-configuration? guix-service + guix-service-type %base-services)) |