add flake structure checks

checks.nix

@@ -0,0 +1,32 @@
+/**
+  All the attributes of this set should be derivations that always build successfully.
+  These are used to validate that this repo and this flake
+*/
+{ self, system, stdenvNoCC, lib, ... }:
+let
+  inherit (lib.asserts) assertMsg;
+  noDerivationTest = { name, errorMsg, checkPhase ? "", assertThat ? true, }:
+    stdenvNoCC.mkDerivation {
+      inherit checkPhase name;
+      dontBuild = true;
+      doCheck = true;
+      src = ./.;
+      installPhase = ''
+        mkdir "$out"
+      '';
+      _ASSERT = assertMsg assertThat errorMsg;
+    };
+in
+{
+  servicesHaveImageAttribute = noDerivationTest {
+    name = "services-have-image-attribute";
+    assertThat = with builtins;
+      let
+        services = self.legacyPackages.${system}.services;
+        hasImageAttr = name: svc: assertMsg (svc ? "image") "expected to find .image attribute in ${svc}";
+      in
+      all (x: x) (attrValues (mapAttrs hasImageAttr services));
+    errorMsg = "expected all services to have a .image attribute";
+  };
+
+}

flake.nix

@@ -29,23 +29,22 @@
         vault-bin = (import nixpkgs-master { system = prev.system; config.allowUnfree = true; }).vault-bin;
       };
       withScripts = final: prev: {
-       scripts = self.legacyPackages.${prev.system}.scripts;
+        scripts = self.legacyPackages.${prev.system}.scripts;
       };
       overlays = [ (import ./overlay.nix) withScripts newVault attic.overlays.default ];
     in
-    {
-      colmena = (import ./hive.nix) (inputs // { inherit overlays; });
-    } // (utils.lib.eachDefaultSystem (system:
+    (utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs {
           inherit system overlays;
           config.allowUnfree = true;
         };
+        pkgsWithSelf = pkgs // {inherit self; };
       in
       rec {
 
         legacyPackages.services = (import ./services) pkgs;
-        legacyPackages.scripts = (import ./scripts) (pkgs // {inherit self; });
+        legacyPackages.scripts = (import ./scripts) pkgsWithSelf;
 
         packages = legacyPackages.scripts;
 
@@ -80,10 +79,14 @@
           VAULT_ADDR = "https://vault.mesh.dcotta.eu:8200";
         };
 
+        checks = (import ./checks.nix) pkgsWithSelf;
+
         formatter = pkgs.writeShellScriptBin "fmt" ''
           ${pkgs.nomad}/bin/nomad fmt
           ${pkgs.terraform}/bin/terraform fmt
         '';
       }
-    ));
+    )) // {
+    colmena = (import ./hive.nix) (inputs // { inherit overlays; }); }
+  ;
 }