nix oci container: add escape hatch to docker config

This now allows to write arbitrary values into the config of the docker
containers generated, if so desired.

It also now creates working directories /before/ executing any preStart
scripts (which would lead to crashes before).

1 files changed, 11 insertions, 10 deletions

diff --git a/nix-modules/docker-nixos-modules.nix b/nix-modules/docker-nixos-modules.nix
index 6ab2785..d14144d 100644
--- a/nix-modules/docker-nixos-modules.nix
+++ b/nix-modules/docker-nixos-modules.nix
@@ -1,5 +1,6 @@
 { nixpkgsPath ? <nixpkgs>
-, ociconfig
+, dockerConfig
+, nixConfig
 , name
 , ...}:
 
@@ -40,7 +41,7 @@ let
   config = pkgs.lib.evalModules {
     modules = [
       systemModule
-      ociconfig
+      nixConfig
       "${nixpkgsPath}/nixos/modules/misc/assertions.nix"
     ];
   };
@@ -66,7 +67,7 @@ in pkgs.dockerTools.buildImage {
   # scripts that are started when the docker container runs.
   # Note that many features of the systemd.services config
   # are just ignored (e.g. no auto-restarts yet)
-  config = with pkgs.lib; with pkgs.lib.strings; {
+  config = with pkgs.lib; with pkgs.lib.strings; dockerConfig // {
     Cmd = pkgs.writeScript "main-entrypoint"
       ("#!${pkgs.dash.outPath}/bin/dash\n" + concatStrings
         (map (command: "${command}&\n")
@@ -75,7 +76,13 @@ in pkgs.dockerTools.buildImage {
               (pkgs.writeScript "systemd-script-${name}"
                 ''
                   #!${pkgs.dash.outPath}/bin/dash
-                  set -ue
+                  set -xue
+
+                  # set up working directory
+                  ${optionalString (service ? serviceConfig
+                          && service.serviceConfig ? WorkingDirectory) ''
+                    mkdir -p ${service.serviceConfig.WorkingDirectory}
+                    cd ${service.serviceConfig.WorkingDirectory} ''}
 
                   # run the prestart script
                   ${optionalString (service ? preStart) ''
@@ -84,12 +91,6 @@ in pkgs.dockerTools.buildImage {
 
                   echo ${name}: starting ...
 
-                  # set up working directory
-                  ${optionalString (service ? serviceConfig
-                          && service.serviceConfig ? WorkingDirectory) ''
-                    mkdir -p ${service.serviceConfig.WorkingDirectory}
-                    cd ${service.serviceConfig.WorkingDirectory} ''}
-
                   # set up environment variables
                   ${optionalString (service ? environment)
                     (concatStrings