services: guix-build-coordinator: Rework authentication config.

A new authentication approach has been added to the coordinator, so to better
represent the options, this commit changes the configuration to accept
different records, each for different authentication approaches.

* gnu/services/guix.scm (guix-build-coordinator-agent-configuration-uuid,
guix-build-coordinator-agent-configuration-password,
guix-build-coordinator-agent-configuration-password-file): Removed
procedures.
(guix-build-coordinator-agent-password-auth,
guix-build-coordinator-agent-password-auth?,
guix-build-coordinator-agent-password-auth-uuid,
guix-build-coordinator-agent-password-auth-password,
guix-build-coordinator-agent-password-file-auth,
guix-build-coordinator-agent-password-file-auth?,
guix-build-coordinator-agent-password-file-auth-uuid,
guix-build-coordinator-agent-password-file-auth-password-file): New
procedures.
(guix-build-coordinator-agent-shepherd-services): Adjust to handle the
authentication field and it's possible record values.
* doc/guix.texi (Guix Build Coordinator): Update documentation.

doc/guix.texi

@@ -30962,18 +30962,9 @@ The system user to run the service as.
 @item @code{coordinator} (default: @code{"http://localhost:8745"})
 The URI to use when connecting to the coordinator.
-@item @code{uuid}
-The UUID of the agent.  This should be generated by the coordinator
-process, stored in the coordinator database, and used by the intended
-agent.
-
-@item @code{password} (default: @code{#f})
-The password to use when connecting to the coordinator.  A file to read
-the password from can also be specified, and this is more secure.
-
-@item @code{password-file} (default: @code{#f})
-A file containing the password to use when connecting to the
-coordinator.
+@item @code{authentication}
+Record describing how this agent should authenticate with the
+coordinator.  Possible record types are described below.
 @item @code{systems} (default: @code{#f})
 The systems for which this agent should fetch builds.  The agent process
@@ -30993,6 +30984,39 @@ input store items aren't already available.
 @end table
 @end deftp
+@deftp {Data Type} guix-build-coordinator-agent-password-auth
+Data type representing an agent authenticating with a coordinator via a
+UUID and password.
+
+@table @asis
+@item @code{uuid}
+The UUID of the agent.  This should be generated by the coordinator
+process, stored in the coordinator database, and used by the intended
+agent.
+
+@item @code{password}
+The password to use when connecting to the coordinator.
+
+@end table
+@end deftp
+
+@deftp {Data Type} guix-build-coordinator-agent-password-file-auth
+Data type representing an agent authenticating with a coordinator via a
+UUID and password read from a file.
+
+@table @asis
+@item @code{uuid}
+The UUID of the agent.  This should be generated by the coordinator
+process, stored in the coordinator database, and used by the intended
+agent.
+
+@item @code{password-file}
+A file containing the password to use when connecting to the
+coordinator.
+
+@end table
+@end deftp
+
 The Guix Build Coordinator package contains a script to query an
 instance of the Guix Data Service for derivations to build, and then
 submit builds for those derivations to the coordinator.  The service

gnu/services/guix.scm

@@ -55,14 +55,22 @@ (define-module (gnu services guix)
             guix-build-coordinator-agent-configuration-package
             guix-build-coordinator-agent-configuration-user
             guix-build-coordinator-agent-configuration-coordinator
-            guix-build-coordinator-agent-configuration-uuid
-            guix-build-coordinator-agent-configuration-password
-            guix-build-coordinator-agent-configuration-password-file
+            guix-build-coordinator-agent-configuration-authentication
             guix-build-coordinator-agent-configuration-systems
             guix-build-coordinator-agent-configuration-max-parallel-builds
             guix-build-coordinator-agent-configuration-derivation-substitute-urls
             guix-build-coordinator-agent-configuration-non-derivation-substitute-urls
 
+            guix-build-coordinator-agent-password-auth
+            guix-build-coordinator-agent-password-auth?
+            guix-build-coordinator-agent-password-auth-uuid
+            guix-build-coordinator-agent-password-auth-password
+
+            guix-build-coordinator-agent-password-file-auth
+            guix-build-coordinator-agent-password-file-auth?
+            guix-build-coordinator-agent-password-file-auth-uuid
+            guix-build-coordinator-agent-password-file-auth-password-file
+
             guix-build-coordinator-agent-service-type
 
             guix-build-coordinator-queue-builds-configuration
@@ -132,11 +140,7 @@ (define-record-type* <guix-build-coordinator-agent-configuration>
                        (default "guix-build-coordinator-agent"))
   (coordinator         guix-build-coordinator-agent-configuration-coordinator
                        (default "http://localhost:8745"))
-  (uuid                guix-build-coordinator-agent-configuration-uuid)
-  (password            guix-build-coordinator-agent-configuration-password
-                       (default #f))
-  (password-file       guix-build-coordinator-agent-configuration-password-file
-                       (default #f))
+  (authentication      guix-build-coordinator-agent-configuration-authentication)
   (systems             guix-build-coordinator-agent-configuration-systems
                        (default #f))
   (max-parallel-builds
@@ -149,6 +153,21 @@ (define-record-type* <guix-build-coordinator-agent-configuration>
    guix-build-coordinator-agent-configuration-non-derivation-substitute-urls
    (default #f)))
 
+(define-record-type* <guix-build-coordinator-agent-password-auth>
+  guix-build-coordinator-agent-password-auth
+  make-guix-build-coordinator-agent-password-auth
+  guix-build-coordinator-agent-password-auth?
+  (uuid                guix-build-coordinator-agent-password-auth-uuid)
+  (password            guix-build-coordinator-agent-password-auth-password))
+
+(define-record-type* <guix-build-coordinator-agent-password-file-auth>
+  guix-build-coordinator-agent-password-file-auth
+  make-guix-build-coordinator-agent-password-file-auth
+  guix-build-coordinator-agent-password-file-auth?
+  (uuid                guix-build-coordinator-agent-password-file-auth-uuid)
+  (password-file
+   guix-build-coordinator-agent-password-file-auth-password-file))
+
 (define-record-type* <guix-build-coordinator-queue-builds-configuration>
   guix-build-coordinator-queue-builds-configuration
   make-guix-build-coordinator-queue-builds-configuration
@@ -326,7 +345,7 @@ (define guix-build-coordinator-service-type
 
 (define (guix-build-coordinator-agent-shepherd-services config)
   (match-record config <guix-build-coordinator-agent-configuration>
-    (package user coordinator uuid password password-file max-parallel-builds
+    (package user coordinator authentication max-parallel-builds
              derivation-substitute-urls non-derivation-substitute-urls
              systems)
     (list
@@ -337,13 +356,16 @@ (define (guix-build-coordinator-agent-shepherd-services config)
       (start #~(make-forkexec-constructor
                 (list #$(file-append package "/bin/guix-build-coordinator-agent")
                       #$(string-append "--coordinator=" coordinator)
-                      #$(string-append "--uuid=" uuid)
-                      #$@(if password
-                             #~(#$(string-append "--password=" password))
-                             #~())
-                      #$@(if password-file
-                             #~(#$(string-append "--password-file=" password-file))
-                             #~())
+                      #$@(match authentication
+                           (($ <guix-build-coordinator-agent-password-auth>
+                               uuid password)
+                            #~(#$(string-append "--uuid=" uuid)
+                               #$(string-append "--password=" password)))
+                           (($ <guix-build-coordinator-agent-password-file-auth>
+                               uuid password-file)
+                            #~(#$(string-append "--uuid=" uuid)
+                               #$(string-append "--password-file="
+                                                password-file))))
                       #$(simple-format #f "--max-parallel-builds=~A"
                                        max-parallel-builds)
                       #$@(if derivation-substitute-urls