Subject: [bug#73196] [PATCH] services: postgresql-role: Add support for password files.

From: Giacomo Leidi <[email-masked]>
Date: Thu, 12 Sep 2024 13:24:23 +0200

This commit adds a password-file to the postgresql-role field.  It
allows users to provision Postgres roles with a set password.

* gnu/services/databases.scm (postgresql-role): Add password-file field;
(postgresql-role-configuration): add requirement field;
(postgresql-create-roles): add support for setting passwords from a
file without leaking passwords to the command line;
(postgresql-role-shepherd-service): add support for customizable
requirements.
* gnu/tests/databases.scm: Test it.
* doc/guix.texi: Document it.

Change-Id: I3aabaa10b0c5e826c5aa874e5649e25a3508a585
---
 doc/guix.texi              | 15 +++++++++---
 gnu/services/databases.scm | 47 +++++++++++++++++++++++++++++++++-----
 gnu/tests/databases.scm    | 38 +++++++++++++++++++++++++++---
 3 files changed, 88 insertions(+), 12 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 981ffb8c58..8e6f1b8b2a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -26294,9 +26294,10 @@ Database Services
 
 @lisp
 (service-extension postgresql-role-service-type
-                   (const (postgresql-role
-                           (name "alice")
-                           (create-database? #t))))
+                   (const (list
+                           (postgresql-role
+                            (name "alice")
+                            (create-database? #t)))))
 @end lisp
 @end defvar
 
@@ -26319,6 +26320,10 @@ Database Services
 @item @code{create-database?} (default: @code{#f})
 whether to create a database with the same name as the role.
 
+@item @code{password-file} (default: @code{#f})
+A string representing the path of a file that contains the password to be set
+for the role.
+
 @item @code{encoding} (default: @code{"UTF8"})
 The character set to use for storing text in the database.
 
@@ -26347,6 +26352,10 @@ Database Services
 @item @code{log} (default: @code{"/var/log/postgresql_roles.log"})
 File name of the log file.
 
+@item @code{requirement} (default: @code{'()}) (type: list-of-symbols)
+Set additional Shepherd services dependencies to the provisioned
+Shepherd service.
+
 @item @code{roles} (default: @code{'()})
 The initial PostgreSQL roles to create.
 @end table
diff --git a/gnu/services/databases.scm b/gnu/services/databases.scm
index fa332d7978..d23dba60e3 100644
--- a/gnu/services/databases.scm
+++ b/gnu/services/databases.scm
@@ -9,6 +9,7 @@
 ;;; Copyright © 2020, 2022 Marius Bakke <[email-masked]>
 ;;; Copyright © 2021 David Larsson <[email-masked]>
 ;;; Copyright © 2021 Aljosha Papsch <[email-masked]>
+;;; Copyright © 2024 Giacomo Leidi <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -31,6 +32,7 @@ (define-module (gnu services databases)
   #:use-module (gnu system shadow)
   #:use-module (gnu packages admin)
   #:use-module (gnu packages base)
+  #:use-module (gnu packages bash)
   #:use-module (gnu packages databases)
   #:use-module (guix build-system trivial)
   #:use-module (guix build union)
@@ -65,11 +67,13 @@ (define-module (gnu services databases)
             postgresql-role
             postgresql-role?
             postgresql-role-name
+            postgresql-role-password-file
             postgresql-role-permissions
             postgresql-role-create-database?
             postgresql-role-configuration
             postgresql-role-configuration?
             postgresql-role-configuration-host
+            postgresql-role-configuration-requirement
             postgresql-role-configuration-roles
 
             postgresql-role-service-type
@@ -372,6 +376,8 @@ (define-record-type* <postgresql-role>
   postgresql-role make-postgresql-role
   postgresql-role?
   (name             postgresql-role-name) ;string
+  (password-file    postgresql-role-password-file  ;string
+                    (default #f))
   (permissions      postgresql-role-permissions
                     (default '(createdb login))) ;list
   (create-database? postgresql-role-create-database?  ;boolean
@@ -390,6 +396,8 @@ (define-record-type* <postgresql-role-configuration>
   postgresql-role-configuration?
   (host             postgresql-role-configuration-host ;string
                     (default "/var/run/postgresql"))
+  (requirement      postgresql-role-configuration-requirement ;list-of-symbols
+                    (default '()))
   (log              postgresql-role-configuration-log ;string
                     (default "/var/log/postgresql_roles.log"))
   (roles            postgresql-role-configuration-roles
@@ -407,19 +415,36 @@ (define (postgresql-create-roles config)
                                permissions)
                    " ")))
 
+  (define (password-value role)
+    (string-append "password_" (postgresql-role-name role)))
+
+  (define (role->password-variable role)
+            (define file-name
+              (postgresql-role-password-file role))
+            (if (string? file-name)
+                ;; This way passwords do not leak to the command line
+                (string-append "-v \"" (password-value role)
+                               "=$(cat " file-name ")\"")
+                ""))
+
   (define (roles->queries roles)
     (apply mixed-text-file "queries"
            (append-map
             (lambda (role)
               (match-record role <postgresql-role>
                 (name permissions create-database? encoding collation ctype
-                      template)
+                      template password-file)
                 `("SELECT NOT(EXISTS(SELECT 1 FROM pg_catalog.pg_roles WHERE \
 rolname = '" ,name "')) as not_exists;\n"
 "\\gset\n"
 "\\if :not_exists\n"
 "CREATE ROLE \"" ,name "\""
 " WITH " ,(format-permissions permissions)
+,(if (and (string? password-file)
+          (not (string-null? password-file)))
+     (string-append
+      "\nPASSWORD :'" (password-value role) "'")
+     "")
 ";\n"
 ,@(if create-database?
       `("CREATE DATABASE \"" ,name "\""
@@ -434,20 +459,30 @@ (define (postgresql-create-roles config)
 
   (let ((host (postgresql-role-configuration-host config))
         (roles (postgresql-role-configuration-roles config)))
-    #~(let ((psql #$(file-append postgresql "/bin/psql")))
-        (list psql "-a" "-h" #$host "-f" #$(roles->queries roles)))))
+    (program-file "run-queries"
+      #~(let ((bash #$(file-append bash-minimal "/bin/bash"))
+              (psql #$(file-append postgresql "/bin/psql")))
+          (define command
+            (string-append
+             "set -e; exec " psql " -c -a -h " #$host " -f "
+             #$(roles->queries roles) " "
+             (string-join
+              (list
+               #$@(map role->password-variable roles))
+              " ")))
+          (execlp bash bash "-c" command)))))
 
 (define (postgresql-role-shepherd-service config)
   (match-record config <postgresql-role-configuration>
-    (log)
+    (log requirement)
     (list (shepherd-service
-           (requirement '(postgres))
+           (requirement `(postgres ,@requirement))
            (provision '(postgres-roles))
            (one-shot? #t)
            (start
             #~(lambda args
                 (let ((pid (fork+exec-command
-                            #$(postgresql-create-roles config)
+                            (list #$(postgresql-create-roles config))
                             #:user "postgres"
                             #:group "postgres"
                             #:log-file #$log)))
diff --git a/gnu/tests/databases.scm b/gnu/tests/databases.scm
index 7c8b87942f..81484b2954 100644
--- a/gnu/tests/databases.scm
+++ b/gnu/tests/databases.scm
@@ -142,6 +142,8 @@ (define %role-log-file
 
 (define %postgresql-os
   (simple-operating-system
+   (extra-special-file "/password"
+                       (plain-file "password" "hello"))
    (service postgresql-service-type
             (postgresql-configuration
              (postgresql postgresql)
@@ -158,6 +160,10 @@ (define %postgresql-os
              (roles
               (list (postgresql-role
                      (name "root")
+                     (create-database? #t))
+                    (postgresql-role
+                     (name "alice")
+                     (password-file "/password")
                      (create-database? #t))))))))
 
 (define (run-postgresql-test)
@@ -230,14 +236,40 @@ (define (run-postgresql-test)
             (marionette-eval
              '(begin
                 (use-modules (gnu services herd)
+                             (srfi srfi-1)
                              (ice-9 popen))
                 (current-output-port
                  (open-file "/dev/console" "w0"))
+                (every
+                 (lambda (role)
+                   (let* ((port (open-pipe*
+                                 OPEN_READ
+                                 #$(file-append postgresql "/bin/psql")
+                                 "-tA" "-c"
+                                 (string-append
+                                  "SELECT 1 FROM pg_database WHERE"
+                                  " datname='" role "'")))
+                          (output (get-string-all port)))
+                     (close-pipe port)
+                     (string-contains output "1")))
+                 '("root" "alice")))
+             marionette))
+
+          (test-assert "database passwords are set"
+            (marionette-eval
+             '(begin
+                (use-modules (gnu services herd)
+                             (ice-9 match)
+                             (ice-9 popen))
+                (current-output-port
+                 (open-file "/dev/console" "w0"))
+                (setgid (passwd:gid (getpwnam "alice")))
+                (setuid (passwd:uid (getpw "alice")))
+                (setenv "PGPASSWORD" "hello")
                 (let* ((port (open-pipe*
                               OPEN_READ
-                              #$(file-append postgresql "/bin/psql")
-                              "-tA" "-c" "SELECT 1 FROM pg_database WHERE
- datname='root'"))
+                              #$(file-append postgresql "/bin/psql") "-tA" "-c"
+                              "SELECT 1 FROM pg_database WHERE datname='alice'"))
                        (output (get-string-all port)))
                   (close-pipe port)
                   (string-contains output "1")))

base-commit: 590904cca15922e6474fbd3a71af9b3a45b268af
-- 
2.46.0