From 6f305ea5fdb239bdac5ab9c1d7b837f3177a025a Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Wed, 14 Oct 2015 19:17:12 +0200 Subject: guix system: Add 'dmd-graph' command. * guix/scripts/system.scm (dmd-service-node-label, dmd-service-node-type, export-dmd-graph): New procedures. (show-help): Add 'dmd-graph'. (guix-system)[parse-sub-command]: Likewise. Honor it. * doc/guix.texi (Invoking guix system): Document it. (dmd Services): Add an illustration and explanation. * doc/images/dmd-graph.dot: New file. * doc.am (DOT_FILES): Add it. --- doc/guix.texi | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'doc/guix.texi') diff --git a/doc/guix.texi b/doc/guix.texi index 0e0e507714..fd0adfd203 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -7004,6 +7004,12 @@ $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf produces a PDF file showing the extension relations among services. +@anchor{system-dmd-graph} +@item dmd-graph +Emit in Dot/Graphviz format to standard output the @dfn{dependency +graph} of dmd services of the operating system defined in @var{file}. +@xref{dmd Services}, for more information and for an example graph. + @end table @@ -7332,10 +7338,23 @@ setuid-root programs on the system (@pxref{Setuid Programs}). The @code{(gnu services dmd)} provides a way to define services managed by GNU@tie{}dmd, which is GuixSD initialization system---the first process that is started when the system boots, aka. PID@tie{}1 -(@pxref{Introduction,,, dmd, GNU dmd Manual}). The -@var{%dmd-root-service} represents PID@tie{}1, of type -@var{dmd-root-service-type}; it can be extended by passing it lists of -@code{} objects. +(@pxref{Introduction,,, dmd, GNU dmd Manual}). + +Services in dmd can depend on each other. For instance, the SSH daemon +may need to be started after the syslog daemon has been started, which +in turn can only happen once all the file systems have been mounted. +The simple operating system defined earlier (@pxref{Using the +Configuration System}) results in a service graph like this: + +@image{images/dmd-graph,,5in,Typical dmd service graph.} + +You can actually generate such a graph for any operating system +definition using the @command{guix system dmd-graph} command +(@pxref{system-dmd-graph, @command{guix system dmd-graph}}). + +The @var{%dmd-root-service} is a service object representing PID@tie{}1, +of type @var{dmd-root-service-type}; it can be extended by passing it +lists of @code{} objects. @deftp {Data Type} dmd-service The data type representing a service managed by dmd. -- cgit v1.2.3