From 34529a7de434b5a1d79049d17ada3d80c8420e14 Mon Sep 17 00:00:00 2001
From: Kiara Grouwstra <kiara@procolix.eu>
Date: Mon, 23 Jun 2025 19:22:47 +0200
Subject: [PATCH] data model: migration

---
 deployment/data-model-test.nix |  6 ++++++
 deployment/data-model.nix      | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/deployment/data-model-test.nix b/deployment/data-model-test.nix
index 55a0e1d8..053f7ba2 100644
--- a/deployment/data-model-test.nix
+++ b/deployment/data-model-test.nix
@@ -46,6 +46,10 @@ in
               module = { };
               runtime-environment = config.runtime-environments.bar;
             };
+            migrations.boo = {
+              deployment = config.deployments.baz;
+              runtime-environment = config.runtime-environments.bar;
+            };
           }
         );
       in
@@ -54,12 +58,14 @@ in
         has-runtime-environment = lib.isAttrs example.runtime-environments.bar.single-ssh-host.module;
         has-application = lib.isAttrs example.applications.foo.module;
         has-deployment = lib.isAttrs example.deployments.baz.module;
+        has-migration = lib.isAttrs example.migrations.boo.deployment;
       };
     expected = {
       has-runtime-configuration = true;
       has-runtime-environment = true;
       has-application = true;
       has-deployment = true;
+      has-migration = true;
     };
   };
 }
diff --git a/deployment/data-model.nix b/deployment/data-model.nix
index 2a90fc11..78bfefca 100644
--- a/deployment/data-model.nix
+++ b/deployment/data-model.nix
@@ -127,6 +127,23 @@ let
       }
     ];
   };
+  migration = submoduleWith {
+    description = "Migration of a Fediversity deployment to a Fediversity run-time environment";
+    modules = [
+      {
+        options = {
+          deployment = mkOption {
+            description = "Deployment to migrate";
+            type = deployment;
+          };
+          runtime-environment = mkOption {
+            description = "Run-time environment to migrate the deployment to";
+            type = runtime-environment;
+          };
+        };
+      }
+    ];
+  };
 in
 {
   options = {
@@ -146,5 +163,9 @@ in
       description = "Deployment of a configuration of applications to a run-time environment";
       type = attrsOf deployment;
     };
+    migrations = mkOption {
+      description = "Migrations from Fediversity deployments to Fediversity run-time environments";
+      type = attrsOf migration;
+    };
   };
 }