pgadmin4: add option to enable desktop mode

By default, pgadmin4 uses SERVER_MODE = True. This requires
access to system directories (e.g. /var/lib/pgadmin). There is
no easy way to change this mode during runtime. One has to change
or add config files withing pgadmin's directory structure to change it
or add a system-wide config file under `/etc/pgadmin`[1].

This isn't always easy to achive or may not be possible at all. For
those usecases this implements a switch in the pgadmin4 derivation and
adds a new top-level package `pgadmin4-desktopmode`. This builds in
DESKTOP MODE and allows the usage of pgadmin4 without the nixOS module
and without access to system-wide directories.

pgadmin4 module saves the configuration to /etc/pgadmin/config_system.py
pgadmin4-desktopmode tries to read that as well. This normally fails with
a PermissionError, as the config file is owned by the user of the pgadmin module.

With the check-system-config-dir.patch this will just throw a warning
but will continue and not read the file.

If we run pgadmin4-desktopmode as root
(something one really shouldn't do), it can read the config file and fail,
because of the wrong config for desktopmode.

[1]https://www.pgadmin.org/docs/pgadmin4/latest/config_py.html

Signed-off-by: Florian Brandes <florian.brandes@posteo.de>

2 files changed, 38 insertions, 1 deletions

diff --git a/pkgs/tools/admin/pgadmin/check-system-config-dir.patch b/pkgs/tools/admin/pgadmin/check-system-config-dir.patch
new file mode 100644
index 0000000000000..f614bab64e6fd
--- /dev/null
+++ b/pkgs/tools/admin/pgadmin/check-system-config-dir.patch
@@ -0,0 +1,17 @@
+diff --git a/web/config.py b/web/config.py
+index 4774043..5b73fd3 100644
+--- a/web/config.py
++++ b/web/config.py
+@@ -884,6 +884,12 @@ if os.path.exists(system_config_dir + '/config_system.py'):
+         user_config_settings.update(config_system_settings)
+     except ImportError:
+         pass
++    except PermissionError:
++        print(f"Permission denied to open {str(system_config_dir + '/config_system.py')}. \n \
++              If you are running pgadmin4-desktopmode please make sure you disable  \n \
++              the pgadmin NixOS module first. If you rely on settings in \n \
++              {str(system_config_dir + '/config_system.py')}, please check the correct permissions.")
++        pass
+
+ # Update settings for 'LOG_FILE', 'SQLITE_PATH', 'SESSION_DB_PATH',
+ # 'AZURE_CREDENTIAL_CACHE_DIR', 'KERBEROS_CCACHE_DIR', 'STORAGE_DIR'
\ No newline at end of file
diff --git a/pkgs/tools/admin/pgadmin/default.nix b/pkgs/tools/admin/pgadmin/default.nix
index 2f85b4e3aff99..a83d96779de6a 100644
--- a/pkgs/tools/admin/pgadmin/default.nix
+++ b/pkgs/tools/admin/pgadmin/default.nix
@@ -9,6 +9,7 @@
 , fetchPypi
 , postgresqlTestHook
 , postgresql
+, server-mode ? true
 }:
 
 let
@@ -88,6 +89,8 @@ pythonPackages.buildPythonApplication rec {
   patches = [
     # Expose setup.py for later use
     ./expose-setup.py.patch
+    # check for permission of /etc/pgadmin/config_system and don't fail
+    ./check-system-config-dir.patch
   ];
 
   postPatch = ''
@@ -105,6 +108,10 @@ pythonPackages.buildPythonApplication rec {
     sed 's|==|>=|g' -i requirements.txt
     substituteInPlace pkg/pip/setup_pip.py \
       --replace "req = req.replace('psycopg2', 'psycopg2-binary')" "req = req"
+    ${lib.optionalString (!server-mode) ''
+    substituteInPlace web/config.py \
+      --replace "SERVER_MODE = True" "SERVER_MODE = False"
+    ''}
   '';
 
   preBuild = ''
@@ -242,7 +249,20 @@ pythonPackages.buildPythonApplication rec {
   '';
 
   meta = with lib; {
-    description = "Administration and development platform for PostgreSQL";
+    description = "Administration and development platform for PostgreSQL${optionalString (!server-mode) ". Desktop Mode"}";
+    longDescription = ''
+      pgAdmin 4 is designed to meet the needs of both novice and experienced Postgres users alike,
+      providing a powerful graphical interface that simplifies the creation, maintenance and use of database objects.
+      ${if server-mode then ''
+      This version is build with SERVER_MODE set to True (the default). It will require access to `/var/lib/pgadmin`
+      and `/var/log/pgadmin`. This is the default version for the NixOS module `services.pgadmin`.
+      This should NOT be used in combination with the `pgadmin4-desktopmode` package as they will interfere.
+      '' else ''
+      This version is build with SERVER_MODE set to False. It will require access to `~/.pgadmin/`. This version is suitable
+      for single-user deployment or where access to `/var/lib/pgadmin` cannot be granted or the NixOS module cannot be used.
+      This should NOT be used in combination with the NixOS module `pgadmin` as they will interfere.
+      ''}
+    '';
     homepage = "https://www.pgadmin.org/";
     license = licenses.mit;
     changelog = "https://www.pgadmin.org/docs/pgadmin4/latest/release_notes_${lib.versions.major version}_${lib.versions.minor version}.html";