From 45d63bce1728589836079ecbce83c08f8220845a Mon Sep 17 00:00:00 2001
From: Vincent Ambo <tazjin@google.com>
Date: Fri, 15 Nov 2019 23:25:41 +0000
Subject: [PATCH] feat(nix): Filter projects that should be built by CI

Instead of specifying CI projects manually, this filters them to move
the CI configuration into the derivations `meta` attributes.
---
 default.nix                                  | 33 ++++++++++++--------
 services/tazblog/default.nix                 |  1 +
 tools/blog_cli/default.nix                   |  2 ++
 tools/{kms_pass/default.nix => kms_pass.nix} |  4 +--
 4 files changed, 25 insertions(+), 15 deletions(-)
 rename tools/{kms_pass/default.nix => kms_pass.nix} (95%)

diff --git a/default.nix b/default.nix
index 789098667..d7ef5b72b 100644
--- a/default.nix
+++ b/default.nix
@@ -16,7 +16,16 @@ let
   };
   readTree = import ./read-tree.nix;
 
-  localPkgs = self: super:
+  # Derivations that have `meta.enableCI` set to `true` should be
+  # built by the CI system on every commit. This code implements
+  # filtering of all derivations in the local sets against this
+  # condition.
+  filterCI = lib: pkgs: let
+    inherit (lib) collect isDerivation filterAttrsRecursive;
+    ciCondition = _: x: (!isDerivation x) || ((x ? meta.enableCI) && (x.meta.enableCI));
+  in collect isDerivation (filterAttrsRecursive ciCondition pkgs);
+
+  repoPkgs = self: super:
     let config = {
       pkgs = self;
       upstream = super;
@@ -32,19 +41,17 @@ let
       services = readTree ./services config;
       tools = readTree ./tools config;
       third_party = readTree ./third_party config;
-    } // (readTree ./overrides config);
-
-  #   # All projects that should be built by CI should be added here:
-  #   ciProjects = [
-  #     self.kontemplate
-  #     self.nixery
-  #     self.ormolu
-  #     self.terraform-gcp
-  #   ] ++ filter (d: d ? meta.broken && !d.meta.broken) (attrValues self.tazjin);
-  # };
-
+    }
+    # Load overrides into the top-level:
+    // (readTree ./overrides config)
+    # Collect all projects that should be built by CI
+    // {
+      ciProjects = (filterCI super.lib self.services)
+        ++ (filterCI super.lib self.tools)
+        ++ (filterCI super.lib self.third_party);
+    };
 in { ... } @ args: import stableSrc (args // {
-    overlays = [ localPkgs ];
+    overlays = [ repoPkgs ];
     config.allowUnfree = true;
     config.allowBroken = true;
 })
diff --git a/services/tazblog/default.nix b/services/tazblog/default.nix
index 2e75c3c2d..4d9608838 100644
--- a/services/tazblog/default.nix
+++ b/services/tazblog/default.nix
@@ -14,4 +14,5 @@ let
   '';
 in wrapper.overrideAttrs(_: {
   allowSubstitutes = true;
+  meta.enableCI = true;
 })
diff --git a/tools/blog_cli/default.nix b/tools/blog_cli/default.nix
index 8113c9336..717daec86 100644
--- a/tools/blog_cli/default.nix
+++ b/tools/blog_cli/default.nix
@@ -5,4 +5,6 @@ pkgs.buildGoPackage {
   goPackagePath = "github.com/tazjin/personal/blog_cli";
   src = ./.;
   goDeps = ./deps.nix;
+
+  meta.enableCI = true;
 }
diff --git a/tools/kms_pass/default.nix b/tools/kms_pass.nix
similarity index 95%
rename from tools/kms_pass/default.nix
rename to tools/kms_pass.nix
index 113db3022..7005697da 100644
--- a/tools/kms_pass/default.nix
+++ b/tools/kms_pass.nix
@@ -9,7 +9,7 @@
 { pkgs, kms, ... }:
 
 let inherit (pkgs) google-cloud-sdk tree writeShellScriptBin;
-in writeShellScriptBin "pass" ''
+in (writeShellScriptBin "pass" ''
   set -eo pipefail
 
   CMD="$1"
@@ -57,4 +57,4 @@ in writeShellScriptBin "pass" ''
       exit 1
       ;;
   esac
-''
+'') // { meta.enableCI = true; }