From 6a205677b9328b9069a22cabf0ce2c619184e4ad Mon Sep 17 00:00:00 2001
From: Christian Hoener zu Siederdissen <christian.hoener@iohk.io>
Date: Mon, 23 Dec 2024 20:34:08 -0300
Subject: [PATCH] adds building oci containers

---
 .github/workflows/ci-oci.yaml | 47 +++++++++++++++++++++++++++++++++++
 nix/containers.nix            | 18 ++++++++++++++
 nix/outputs.nix               |  6 ++---
 3 files changed, 68 insertions(+), 3 deletions(-)
 create mode 100644 .github/workflows/ci-oci.yaml
 create mode 100644 nix/containers.nix

diff --git a/.github/workflows/ci-oci.yaml b/.github/workflows/ci-oci.yaml
new file mode 100644
index 0000000..5a0b27b
--- /dev/null
+++ b/.github/workflows/ci-oci.yaml
@@ -0,0 +1,47 @@
+# https://github.com/marketplace/actions/install-nix
+
+# Builds oci container in a rather convoluted way.
+
+name: "ci-oci"
+on:
+  pull_request:
+  push:
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+
+    - uses: actions/checkout@v4
+
+    - name: Install nix
+      uses: cachix/install-nix-action@v27
+
+    # https://github.com/marketplace/actions/cache-nix-store
+    - name: Restore and cache Nix store
+      uses: nix-community/cache-nix-action@v5
+      with:
+        # restore and save a cache using this key
+        # TODO: Also hash the cabal.config and *cabal files, since we depend on them
+        primary-key: nix-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
+        # if there's no cache hit, restore a cache by this prefix
+        restore-prefixes-first-match: nix-${{ runner.os }}-
+        # collect garbage until Nix store size (in bytes) is at most this number
+        # before trying to save a new cache
+        gc-max-store-size-linux: 1073741824
+        # do purge caches
+        purge: true
+        # purge all versions of the cache
+        purge-prefixes: cache-${{ runner.os }}-
+        # created more than this number of seconds ago relative to the start of the `Post Restore` phase
+        purge-created: 0
+        # except the version with the `primary-key`, if it exists
+        purge-primary-key: never
+
+    - run: nix build --accept-flake-config .#containers.x86_64-linux.wst.copyTo
+    - run: ./result/bin/copy-to oci-archive:oci.tar
+
diff --git a/nix/containers.nix b/nix/containers.nix
new file mode 100644
index 0000000..8790466
--- /dev/null
+++ b/nix/containers.nix
@@ -0,0 +1,18 @@
+{ repoRoot, inputs, pkgs, lib, system }:
+{
+
+  # Builds a docker container for the cabal executable given as input. First we
+  # build the container json itself. Note the explicit architecture.
+  #
+  # $ nix build .#containers.x86_64-linux.wst
+  #
+  wst = lib.iogx.mkContainerFromCabalExe {
+    exe = inputs.self.packages.wst-poc;
+    name = "wst-poc";
+    description = "WST Proof of Concept";
+    packages = [ ];
+    sourceUrl = "https://github.com/input-output-hk/wsc-poc";
+  };
+
+}
+
diff --git a/nix/outputs.nix b/nix/outputs.nix
index 0d779d2..258aea1 100644
--- a/nix/outputs.nix
+++ b/nix/outputs.nix
@@ -1,9 +1,9 @@
 { repoRoot, inputs, pkgs, lib, system }:
 let
   project = repoRoot.nix.project;
+  containers = repoRoot.nix.containers;
 in
 [
-  (
-    project.flake
-  )
+  ( project.flake )
+  { inherit containers; }
 ]