From dfcab61d0232a2525e9b13b2b49e9f932ccca385 Mon Sep 17 00:00:00 2001
From: Akshay Karle <1443108+akshaykarle@users.noreply.github.com>
Date: Thu, 17 Oct 2024 15:45:40 +0100
Subject: [PATCH] allow building docker images from nix

* https://nixos.wiki/wiki/Docker
* https://lucabrunox.github.io/2016/04/cheap-docker-images-with-nix_15.html
---
 .gitignore |  4 +++-
 flake.nix  | 12 +++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/.gitignore b/.gitignore
index b7c10b4..d738668 100644
--- a/.gitignore
+++ b/.gitignore
@@ -160,4 +160,6 @@ cython_debug/
 .idea/
 
 .direnv/
-file_uploads/
\ No newline at end of file
+file_uploads/
+# nix build results for docker and other packages
+result
\ No newline at end of file
diff --git a/flake.nix b/flake.nix
index 1c1cdb7..b7d6bf6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -61,9 +61,18 @@
             (final: _: { myapp = final.callPackage myapp { }; })
           ];
         };
+        # build docker using nix to have smaller images. Inspiration from
+        # https://lucabrunox.github.io/2016/04/cheap-docker-images-with-nix_15.html
+        buildImage = pkgs.dockerTools.buildLayeredImage {
+          name = "pii";
+          tag = "latest";
+          created = "now";
+          config.Entrypoint = [ "${pkgs.myapp}/bin/cli" ];
+        };
       in
       {
         packages.default = pkgs.myapp;
+        packages.dockerImage = buildImage;
 
         apps.default = {
           type = "app";
@@ -79,8 +88,9 @@
           default = pkgs.mkShell {
             inputsFrom = [ pkgs.myapp ];
             packages = [
-              pkgs.vault
+              pkgs.docker
               pkgs.jq
+              pkgs.vault
             ];
           };