;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (gnu services)
+ #:use-module (guix gexp)
+ #:use-module (guix monads)
+ #:use-module (guix store)
#:use-module (guix records)
- #:export (service?
+ #:use-module (guix profiles)
+ #:use-module (guix sets)
+ #:use-module (guix ui)
+ #:use-module (guix modules)
+ #:use-module (gnu packages base)
+ #:use-module (gnu packages bash)
+ #:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-9)
+ #:use-module (srfi srfi-9 gnu)
+ #:use-module (srfi srfi-26)
+ #:use-module (srfi srfi-34)
+ #:use-module (srfi srfi-35)
+ #:use-module (ice-9 vlist)
+ #:use-module (ice-9 match)
+ #:export (service-extension
+ service-extension?
+ service-extension-target
+ service-extension-compute
+
+ service-type
+ service-type?
+ service-type-name
+ service-type-extensions
+ service-type-compose
+ service-type-extend
+
service
- service-documentation
- service-provision
- service-requirement
- service-respawn?
- service-start
- service-stop
- service-user-accounts
- service-user-groups
- service-pam-services))
+ service?
+ service-kind
+ service-parameters
+
+ simple-service
+ modify-services
+ service-back-edges
+ fold-services
+
+ service-error?
+ missing-target-service-error?
+ missing-target-service-error-service
+ missing-target-service-error-target-type
+ ambiguous-target-service-error?
+ ambiguous-target-service-error-service
+ ambiguous-target-service-error-target-type
+
+ system-service-type
+ boot-service-type
+ cleanup-service-type
+ activation-service-type
+ activation-service->script
+ %linux-bare-metal-service
+ etc-service-type
+ etc-directory
+ setuid-program-service-type
+ profile-service-type
+ firmware-service-type
+ gc-root-service-type
+
+ %boot-service
+ %activation-service
+ etc-service
-;;; Commentary:
+ file-union)) ;XXX: for lack of a better place
+
+;;; Comment:
+;;;
+;;; This module defines a broad notion of "service types" and "services."
+;;;
+;;; A service type describe how its instances extend instances of other
+;;; service types. For instance, some services extend the instance of
+;;; ACCOUNT-SERVICE-TYPE by providing it with accounts and groups to create;
+;;; others extend SHEPHERD-ROOT-SERVICE-TYPE by passing it instances of
+;;; <shepherd-service>.
+;;;
+;;; When applicable, the service type defines how it can itself be extended,
+;;; by providing one procedure to compose extensions, and one procedure to
+;;; extend itself.
+;;;
+;;; A notable service type is SYSTEM-SERVICE-TYPE, which has a single
+;;; instance, which is the root of the service DAG. Its value is the
+;;; derivation that produces the 'system' directory as returned by
+;;; 'operating-system-derivation'.
;;;
-;;; System services as cajoled by dmd.
+;;; The 'fold-services' procedure can be passed a list of procedures, which it
+;;; "folds" by propagating extensions down the graph; it returns the root
+;;; service after the applying all its extensions.
;;;
;;; Code:
-(define-record-type* <service>
- service make-service
+(define-record-type <service-extension>
+ (service-extension target compute)
+ service-extension?
+ (target service-extension-target) ;<service-type>
+ (compute service-extension-compute)) ;params -> params
+
+(define-record-type* <service-type> service-type make-service-type
+ service-type?
+ (name service-type-name) ;symbol (for debugging)
+
+ ;; Things extended by services of this type.
+ (extensions service-type-extensions) ;list of <service-extensions>
+
+ ;; Given a list of extensions, "compose" them.
+ (compose service-type-compose ;list of Any -> Any
+ (default #f))
+
+ ;; Extend the services' own parameters with the extension composition.
+ (extend service-type-extend ;list of Any -> parameters
+ (default #f)))
+
+(define (write-service-type type port)
+ (format port "#<service-type ~a ~a>"
+ (service-type-name type)
+ (number->string (object-address type) 16)))
+
+(set-record-type-printer! <service-type> write-service-type)
+
+;; Services of a given type.
+(define-record-type <service>
+ (service type parameters)
service?
- (documentation service-documentation ; string
- (default "[No documentation.]"))
- (provision service-provision) ; list of symbols
- (requirement service-requirement ; list of symbols
- (default '()))
- (respawn? service-respawn? ; Boolean
- (default #t))
- (start service-start) ; g-expression
- (stop service-stop ; g-expression
- (default #f))
- (user-accounts service-user-accounts ; list of <user-account>
- (default '()))
- (user-groups service-user-groups ; list of <user-groups>
- (default '()))
- (pam-services service-pam-services ; list of <pam-service>
- (default '())))
+ (type service-kind)
+ (parameters service-parameters))
+
+(define (simple-service name target value)
+ "Return a service that extends TARGET with VALUE. This works by creating a
+singleton service type NAME, of which the returned service is an instance."
+ (let* ((extension (service-extension target identity))
+ (type (service-type (name name)
+ (extensions (list extension)))))
+ (service type value)))
+
+(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 and return
+the resulting list of services. 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))))
+
+\f
+;;;
+;;; Core services.
+;;;
+
+(define (system-derivation mentries mextensions)
+ "Return as a monadic value the derivation of the 'system' directory
+containing the given entries."
+ (mlet %store-monad ((entries mentries)
+ (extensions (sequence %store-monad mextensions)))
+ (lower-object
+ (file-union "system"
+ (append entries (concatenate extensions))))))
+
+(define system-service-type
+ ;; This is the ultimate service type, the root of the service DAG. The
+ ;; service of this type is extended by monadic name/item pairs. These items
+ ;; end up in the "system directory" as returned by
+ ;; 'operating-system-derivation'.
+ (service-type (name 'system)
+ (extensions '())
+ (compose identity)
+ (extend system-derivation)))
+
+(define (compute-boot-script _ mexps)
+ (mlet %store-monad ((gexps (sequence %store-monad mexps)))
+ (gexp->file "boot"
+ ;; Clean up and activate the system, then spawn shepherd.
+ #~(begin #$@gexps))))
+
+(define (boot-script-entry mboot)
+ "Return, as a monadic value, an entry for the boot script in the system
+directory."
+ (mlet %store-monad ((boot mboot))
+ (return `(("boot" ,boot)))))
+
+(define boot-service-type
+ ;; The service of this type is extended by being passed gexps as monadic
+ ;; values. It aggregates them in a single script, as a monadic value, which
+ ;; becomes its 'parameters'. It is the only service that extends nothing.
+ (service-type (name 'boot)
+ (extensions
+ (list (service-extension system-service-type
+ boot-script-entry)))
+ (compose append)
+ (extend compute-boot-script)))
+
+(define %boot-service
+ ;; The service that produces the boot script.
+ (service boot-service-type #t))
+
+(define (cleanup-gexp _)
+ "Return as a monadic value a gexp to clean up /tmp and similar places upon
+boot."
+ (with-monad %store-monad
+ (with-imported-modules '((guix build utils))
+ (return #~(begin
+ (use-modules (guix build utils))
+
+ ;; Clean out /tmp and /var/run.
+ ;;
+ ;; XXX This needs to happen before service activations, so it
+ ;; has to be here, but this also implicitly assumes that /tmp
+ ;; and /var/run are on the root partition.
+ (letrec-syntax ((fail-safe (syntax-rules ()
+ ((_ exp rest ...)
+ (begin
+ (catch 'system-error
+ (lambda () exp)
+ (const #f))
+ (fail-safe rest ...)))
+ ((_)
+ #t))))
+ ;; Ignore I/O errors so the system can boot.
+ (fail-safe
+ (delete-file-recursively "/tmp")
+ (delete-file-recursively "/var/run")
+ (mkdir "/tmp")
+ (chmod "/tmp" #o1777)
+ (mkdir "/var/run")
+ (chmod "/var/run" #o755))))))))
+
+(define cleanup-service-type
+ ;; Service that cleans things up in /tmp and similar.
+ (service-type (name 'cleanup)
+ (extensions
+ (list (service-extension boot-service-type
+ cleanup-gexp)))))
+
+(define* (file-union name files) ;FIXME: Factorize.
+ "Return a <computed-file> that builds a directory containing all of FILES.
+Each item in FILES must be a list where the first element is the file name to
+use in the new directory, and the second element is a gexp denoting the target
+file."
+ (computed-file name
+ #~(begin
+ (mkdir #$output)
+ (chdir #$output)
+ #$@(map (match-lambda
+ ((target source)
+ #~(begin
+ ;; Stat the source to abort early if it
+ ;; does not exist.
+ (stat #$source)
+
+ (symlink #$source #$target))))
+ files))))
+
+(define (directory-union name things)
+ "Return a directory that is the union of THINGS."
+ (match things
+ ((one)
+ ;; Only one thing; return it.
+ one)
+ (_
+ (computed-file name
+ (with-imported-modules '((guix build union))
+ #~(begin
+ (use-modules (guix build union))
+ (union-build #$output '#$things)))))))
+
+(define* (activation-service->script service)
+ "Return as a monadic value the activation script for SERVICE, a service of
+ACTIVATION-SCRIPT-TYPE."
+ (activation-script (service-parameters service)))
+
+(define (activation-script gexps)
+ "Return the system's activation script, which evaluates GEXPS."
+ (define (service-activations)
+ ;; Return the activation scripts for SERVICES.
+ (mapm %store-monad
+ (cut gexp->file "activate-service" <>)
+ gexps))
+
+ (mlet* %store-monad ((actions (service-activations)))
+ (gexp->file "activate"
+ (with-imported-modules (source-module-closure
+ '((gnu build activation)))
+ #~(begin
+ (use-modules (gnu build activation))
+
+ ;; Make sure /bin/sh is valid and current.
+ (activate-/bin/sh
+ (string-append #$(canonical-package bash) "/bin/sh"))
+
+ ;; Make sure the user accounting database exists. If it
+ ;; does not exist, 'setutxent' does not create it and
+ ;; thus there is no accounting at all.
+ (close-port (open-file "/var/run/utmpx" "a0"))
+
+ ;; Set up /run/current-system. Among other things this
+ ;; sets up locales, which the activation snippets
+ ;; executed below may expect.
+ (activate-current-system)
+
+ ;; Run the services' activation snippets.
+ ;; TODO: Use 'load-compiled'.
+ (for-each primitive-load '#$actions))))))
+
+(define (gexps->activation-gexp gexps)
+ "Return a gexp that runs the activation script containing GEXPS."
+ (mlet %store-monad ((script (activation-script gexps)))
+ (return #~(primitive-load #$script))))
+
+(define (second-argument a b) b)
+
+(define activation-service-type
+ (service-type (name 'activate)
+ (extensions
+ (list (service-extension boot-service-type
+ gexps->activation-gexp)))
+ (compose append)
+ (extend second-argument)))
+
+(define %activation-service
+ ;; The activation service produces the activation script from the gexps it
+ ;; receives.
+ (service activation-service-type #t))
+
+(define %modprobe-wrapper
+ ;; Wrapper for the 'modprobe' command that knows where modules live.
+ ;;
+ ;; This wrapper is typically invoked by the Linux kernel ('call_modprobe',
+ ;; in kernel/kmod.c), a situation where the 'LINUX_MODULE_DIRECTORY'
+ ;; environment variable is not set---hence the need for this wrapper.
+ (let ((modprobe "/run/current-system/profile/bin/modprobe"))
+ (program-file "modprobe"
+ #~(begin
+ (setenv "LINUX_MODULE_DIRECTORY"
+ "/run/booted-system/kernel/lib/modules")
+ (apply execl #$modprobe
+ (cons #$modprobe (cdr (command-line))))))))
+
+(define %linux-kernel-activation
+ ;; Activation of the Linux kernel running on the bare metal (as opposed to
+ ;; running in a container.)
+ #~(begin
+ ;; Tell the kernel to use our 'modprobe' command.
+ (activate-modprobe #$%modprobe-wrapper)
+
+ ;; Let users debug their own processes!
+ (activate-ptrace-attach)))
+
+(define linux-bare-metal-service-type
+ (service-type (name 'linux-bare-metal)
+ (extensions
+ (list (service-extension activation-service-type
+ (const %linux-kernel-activation))))))
+
+(define %linux-bare-metal-service
+ ;; The service that does things that are needed on the "bare metal", but not
+ ;; necessary or impossible in a container.
+ (service linux-bare-metal-service-type #f))
+
+(define (etc-directory service)
+ "Return the directory for SERVICE, a service of type ETC-SERVICE-TYPE."
+ (files->etc-directory (service-parameters service)))
+
+(define (files->etc-directory files)
+ (file-union "etc" files))
+
+(define (etc-entry files)
+ "Return an entry for the /etc directory consisting of FILES in the system
+directory."
+ (with-monad %store-monad
+ (return `(("etc" ,(files->etc-directory files))))))
+
+(define etc-service-type
+ (service-type (name 'etc)
+ (extensions
+ (list
+ (service-extension activation-service-type
+ (lambda (files)
+ (let ((etc
+ (files->etc-directory files)))
+ #~(activate-etc #$etc))))
+ (service-extension system-service-type etc-entry)))
+ (compose concatenate)
+ (extend append)))
+
+(define (etc-service files)
+ "Return a new service of ETC-SERVICE-TYPE that populates /etc with FILES.
+FILES must be a list of name/file-like object pairs."
+ (service etc-service-type files))
+
+(define setuid-program-service-type
+ (service-type (name 'setuid-program)
+ (extensions
+ (list (service-extension activation-service-type
+ (lambda (programs)
+ #~(activate-setuid-programs
+ (list #$@programs))))))
+ (compose concatenate)
+ (extend append)))
+
+(define (packages->profile-entry packages)
+ "Return a system entry for the profile containing PACKAGES."
+ (mlet %store-monad ((profile (profile-derivation
+ (packages->manifest
+ (delete-duplicates packages eq?)))))
+ (return `(("profile" ,profile)))))
+
+(define profile-service-type
+ ;; The service that populates the system's profile---i.e.,
+ ;; /run/current-system/profile. It is extended by package lists.
+ (service-type (name 'profile)
+ (extensions
+ (list (service-extension system-service-type
+ packages->profile-entry)))
+ (compose concatenate)
+ (extend append)))
+
+(define (firmware->activation-gexp firmware)
+ "Return a gexp to make the packages listed in FIRMWARE loadable by the
+kernel."
+ (let ((directory (directory-union "firmware" firmware)))
+ ;; Tell the kernel where firmware is.
+ #~(activate-firmware (string-append #$directory "/lib/firmware"))))
+
+(define firmware-service-type
+ ;; The service that collects firmware.
+ (service-type (name 'firmware)
+ (extensions
+ (list (service-extension activation-service-type
+ firmware->activation-gexp)))
+ (compose concatenate)
+ (extend append)))
+
+(define (gc-roots->system-entry roots)
+ "Return an entry in the system's output containing symlinks to ROOTS."
+ (mlet %store-monad ((entry (gexp->derivation
+ "gc-roots"
+ #~(let ((roots '#$roots))
+ (mkdir #$output)
+ (chdir #$output)
+ (for-each symlink
+ roots
+ (map number->string
+ (iota (length roots))))))))
+ (return (if (null? roots)
+ '()
+ `(("gc-roots" ,entry))))))
+
+(define gc-root-service-type
+ ;; A service to associate extra garbage-collector roots to the system. This
+ ;; is a simple hack that guarantees that the system retains references to
+ ;; the given list of roots. Roots must be "lowerable" objects like
+ ;; packages, or derivations.
+ (service-type (name 'gc-roots)
+ (extensions
+ (list (service-extension system-service-type
+ gc-roots->system-entry)))
+ (compose concatenate)
+ (extend append)))
+
+\f
+;;;
+;;; Service folding.
+;;;
+
+(define-condition-type &service-error &error
+ service-error?)
+
+(define-condition-type &missing-target-service-error &service-error
+ missing-target-service-error?
+ (service missing-target-service-error-service)
+ (target-type missing-target-service-error-target-type))
+
+(define-condition-type &ambiguous-target-service-error &service-error
+ ambiguous-target-service-error?
+ (service ambiguous-target-service-error-service)
+ (target-type ambiguous-target-service-error-target-type))
+
+(define (service-back-edges services)
+ "Return a procedure that, when passed a <service>, returns the list of
+<service> objects that depend on it."
+ (define (add-edges service edges)
+ (define (add-edge extension edges)
+ (let ((target-type (service-extension-target extension)))
+ (match (filter (lambda (service)
+ (eq? (service-kind service) target-type))
+ services)
+ ((target)
+ (vhash-consq target service edges))
+ (()
+ (raise
+ (condition (&missing-target-service-error
+ (service service)
+ (target-type target-type))
+ (&message
+ (message
+ (format #f (_ "no target of type '~a' for service ~s")
+ (service-type-name target-type)
+ service))))))
+ (x
+ (raise
+ (condition (&ambiguous-target-service-error
+ (service service)
+ (target-type target-type))
+ (&message
+ (message
+ (format #f
+ (_ "more than one target service of type '~a'")
+ (service-type-name target-type))))))))))
+
+ (fold add-edge edges (service-type-extensions (service-kind service))))
+
+ (let ((edges (fold add-edges vlist-null services)))
+ (lambda (node)
+ (reverse (vhash-foldq* cons '() node edges)))))
+
+(define* (fold-services services
+ #:key (target-type system-service-type))
+ "Fold SERVICES by propagating their extensions down to the root of type
+TARGET-TYPE; return the root service adjusted accordingly."
+ (define dependents
+ (service-back-edges services))
+
+ (define (matching-extension target)
+ (let ((target (service-kind target)))
+ (match-lambda
+ (($ <service-extension> type)
+ (eq? type target)))))
+
+ (define (apply-extension target)
+ (lambda (service)
+ (match (find (matching-extension target)
+ (service-type-extensions (service-kind service)))
+ (($ <service-extension> _ compute)
+ (compute (service-parameters service))))))
+
+ (match (filter (lambda (service)
+ (eq? (service-kind service) target-type))
+ services)
+ ((sink)
+ (let loop ((sink sink))
+ (let* ((dependents (map loop (dependents sink)))
+ (extensions (map (apply-extension sink) dependents))
+ (extend (service-type-extend (service-kind sink)))
+ (compose (service-type-compose (service-kind sink)))
+ (params (service-parameters sink)))
+ ;; We distinguish COMPOSE and EXTEND because PARAMS typically has a
+ ;; different type than the elements of EXTENSIONS.
+ (if extend
+ (service (service-kind sink)
+ (extend params (compose extensions)))
+ sink))))
+ (()
+ (raise
+ (condition (&missing-target-service-error
+ (service #f)
+ (target-type target-type))
+ (&message
+ (message (format #f (_ "service of type '~a' not found")
+ (service-type-name target-type)))))))
+ (x
+ (raise
+ (condition (&ambiguous-target-service-error
+ (service #f)
+ (target-type target-type))
+ (&message
+ (message
+ (format #f
+ (_ "more than one target service of type '~a'")
+ (service-type-name target-type)))))))))
;;; services.scm ends here.
HCoop / jackhill / guix / guix.git / blobdiff