chore(nix): Move files around to conform to new read-tree layout

Broadly speaking, the following things are included:

* there is now a uniform `args` struct that is passed to all
  derivations, package headers have been changed appropriately
* overrides are now loaded from a separate `override` folder just
  using read-tree.nix
* third-party packages have moved into the `third_party` attribute set

19 files changed, 112 insertions, 102 deletions

diff --git a/default.nix b/default.nix
index 93e2d9fc54..789098667a 100644
--- a/default.nix
+++ b/default.nix
@@ -14,78 +14,34 @@ let
     url = "https://github.com/NixOS/nixpkgs-channels/archive/${stableCommit}.tar.gz";
     sha256 = "0243qiivxl3z51biy4f5y5cy81x5bki5dazl9wqwgnmd373gpmxy";
   };
+  readTree = import ./read-tree.nix;
 
-  localPkgs = self: super: {
-    # Local projects should be added here:
-    tazjin = {
-      blog = self.callPackage ./services/tazblog {};
-      blog_cli = self.callPackage ./tools/blog_cli {};
-      gemma = self.callPackage ./services/gemma {};
-      nixcon = self.naersk.buildPackage ./services/nixcon-demo {};
+  localPkgs = self: super:
+    let config = {
+      pkgs = self;
+      upstream = super;
 
-      kms_pass = self.callPackage ./tools/kms_pass {
+      kms = {
         project = "tazjins-infrastructure";
         region = "europe-north1";
         keyring = "tazjins-keys";
         key = "kontemplate-key";
       };
     };
-
-    # Third-party projects (either vendored or modified from nixpkgs) go here:
-    nixery = import ./third_party/nixery.nix { pkgs = self; };
-    terraform-gcp = self.terraform_0_12.withPlugins(p: [ p.google p.google-beta ]);
-    ormolu = import (self.fetchFromGitHub {
-      owner = "tweag";
-      repo = "ormolu";
-      rev = "a7076c0f83e5c06ea9067b71171859fa2ba8afd9";
-      sha256 = "1p4n2ja4ciw3qfskn65ggpy37mvgf2sslxqmqn8s8jjarnqcyfny";
-    }) { pkgs = self; };
-    naersk = self.callPackage (self.fetchFromGitHub {
-      owner = "nmattia";
-      repo = "naersk";
-      rev = "68c1c2b2b661913cdc5ecabea518dfdc4f449027";
-      sha256 = "1ll310pl44kdbwfslzwvg2v7khf1y0xkg2j5wcfia4k7sj6bcl28";
-    }) {};
-
-    # Gemma needs an older version of Elm to be built. Updating it to
-    # the newer version is a lot of effort.
-    elmPackages = (import (self.fetchFromGitHub {
-      owner = "NixOS";
-      repo = "nixpkgs";
-      rev = "14f9ee66e63077539252f8b4550049381a082518";
-      sha256 = "1wn7nmb1cqfk2j91l3rwc6yhimfkzxprb8wknw5wi57yhq9m6lv1";
-    }) {}).elmPackages;
-
-    # Wrap kontemplate to inject the Cloud KMS version of 'pass'
-    kontemplate =
-      let master = super.kontemplate.overrideAttrs(_: {
-        src = self.fetchFromGitHub {
-          owner = "tazjin";
-          repo = "kontemplate";
-          rev = "v1.8.0";
-          sha256 = "123mjmmm4hynraq1fpn3j5i0a1i87l265kkjraxxxbl0zacv74i1";
-        };
-      });
-      in self.writeShellScriptBin "kontemplate" ''
-        export PATH="${self.tazjin.kms_pass}/bin:$PATH"
-        exec ${master}/bin/kontemplate $@
-      '';
-
-    # One of Gemma's dependencies is missing in nixpkgs' Quicklisp
-    # package set, it is overlaid locally here.
-    lispPackages = import ./third_party/common_lisp/quicklisp.nix {
-      inherit (self) lib;
-      inherit (super) lispPackages;
-    };
-
-    # 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);
-  };
+    in {
+      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);
+  # };
 
 in { ... } @ args: import stableSrc (args // {
     overlays = [ localPkgs ];
diff --git a/overrides/elmPackages.nix b/overrides/elmPackages.nix
new file mode 100644
index 0000000000..3df44420a6
--- /dev/null
+++ b/overrides/elmPackages.nix
@@ -0,0 +1,10 @@
+# Gemma needs an older version of Elm to be built. Updating it to
+# the newer version is a lot of effort.
+{ pkgs, ... }:
+
+(import (pkgs.fetchFromGitHub {
+  owner = "NixOS";
+  repo = "nixpkgs";
+  rev = "14f9ee66e63077539252f8b4550049381a082518";
+  sha256 = "1wn7nmb1cqfk2j91l3rwc6yhimfkzxprb8wknw5wi57yhq9m6lv1";
+}) {}).elmPackages
diff --git a/overrides/kontemplate.nix b/overrides/kontemplate.nix
new file mode 100644
index 0000000000..28381b0137
--- /dev/null
+++ b/overrides/kontemplate.nix
@@ -0,0 +1,14 @@
+{ pkgs, upstream, ... }:
+
+let master = upstream.kontemplate.overrideAttrs(_: {
+  src = pkgs.fetchFromGitHub {
+    owner = "tazjin";
+    repo = "kontemplate";
+    rev = "v1.8.0";
+    sha256 = "123mjmmm4hynraq1fpn3j5i0a1i87l265kkjraxxxbl0zacv74i1";
+  };
+});
+in pkgs.writeShellScriptBin "kontemplate" ''
+  export PATH="${pkgs.tools.kms_pass}/bin:$PATH"
+  exec ${master}/bin/kontemplate $@
+''
diff --git a/overrides/lispPackages/default.nix b/overrides/lispPackages/default.nix
new file mode 100644
index 0000000000..da8f3c893a
--- /dev/null
+++ b/overrides/lispPackages/default.nix
@@ -0,0 +1,8 @@
+# One of Gemma's dependencies is missing in nixpkgs' Quicklisp
+# package set, it is overlaid locally here.
+{ pkgs, upstream, ... }:
+
+import ./quicklisp.nix {
+  inherit (pkgs) lib;
+  inherit (upstream) lispPackages;
+}
diff --git a/third_party/common_lisp/quicklisp-to-nix-output/cl-prevalence.nix b/overrides/lispPackages/quicklisp-to-nix-output/cl-prevalence.nix
index 4e5e3ec5d6..4e5e3ec5d6 100644
--- a/third_party/common_lisp/quicklisp-to-nix-output/cl-prevalence.nix
+++ b/overrides/lispPackages/quicklisp-to-nix-output/cl-prevalence.nix
diff --git a/third_party/common_lisp/quicklisp-to-nix-output/s-sysdeps.nix b/overrides/lispPackages/quicklisp-to-nix-output/s-sysdeps.nix
index 1c28ec6e2a..1c28ec6e2a 100644
--- a/third_party/common_lisp/quicklisp-to-nix-output/s-sysdeps.nix
+++ b/overrides/lispPackages/quicklisp-to-nix-output/s-sysdeps.nix
diff --git a/third_party/common_lisp/quicklisp-to-nix-output/s-xml.nix b/overrides/lispPackages/quicklisp-to-nix-output/s-xml.nix
index ec12dde522..ec12dde522 100644
--- a/third_party/common_lisp/quicklisp-to-nix-output/s-xml.nix
+++ b/overrides/lispPackages/quicklisp-to-nix-output/s-xml.nix
diff --git a/third_party/common_lisp/quicklisp.nix b/overrides/lispPackages/quicklisp.nix
index a0040f1d6f..1d23db762d 100644
--- a/third_party/common_lisp/quicklisp.nix
+++ b/overrides/lispPackages/quicklisp.nix
@@ -1,6 +1,3 @@
-# Overlay over `pkgs.lispPackages` that adds additional packages which
-# are missing from the imported Quicklisp package set in nixpkgs.
-
 { lib, lispPackages }:
 
 let inherit (lispPackages) buildLispPackage qlOverrides fetchurl;
diff --git a/read-tree.nix b/read-tree.nix
index 00a2e738bd..d883d12c81 100644
--- a/read-tree.nix
+++ b/read-tree.nix
@@ -1,4 +1,4 @@
-path: self: super:
+path: { pkgs, ... } @ args:
 
 let
   inherit (builtins)
@@ -15,8 +15,6 @@ let
     toPath
     toString;
 
-  args = { pkgs = self; };
-
   zipAttrs = names: values:
     if (names == []) || (values == [])
     then []
diff --git a/services/gemma/default.nix b/services/gemma/default.nix
index 409d8eef38..ea10a4c7d0 100644
--- a/services/gemma/default.nix
+++ b/services/gemma/default.nix
@@ -1,17 +1,20 @@
-{ stdenv, sbcl, lispPackages, elmPackages, makeWrapper, openssl }:
-
-let frontend = stdenv.mkDerivation {
-  name = "gemma-frontend";
-  src = ./frontend;
-  buildInputs = [ elmPackages.elm ];
-
-  phases = [ "unpackPhase" "buildPhase" ];
-  buildPhase = ''
-    mkdir .home && export HOME="$PWD/.home"
-    mkdir -p $out
-    elm-make --yes Main.elm --output $out/index.html
-  '';
-};
+{ pkgs, ... }:
+
+let
+  inherit (pkgs) stdenv sbcl lispPackages elmPackages makeWrapper openssl;
+
+  frontend = stdenv.mkDerivation {
+    name = "gemma-frontend";
+    src = ./frontend;
+    buildInputs = [ elmPackages.elm ];
+
+    phases = [ "unpackPhase" "buildPhase" ];
+    buildPhase = ''
+      mkdir .home && export HOME="$PWD/.home"
+      mkdir -p $out
+      elm-make --yes Main.elm --output $out/index.html
+    '';
+  };
 in stdenv.mkDerivation rec {
   name = "gemma";
   src = ./.;
diff --git a/services/nixcon-demo/default.nix b/services/nixcon-demo/default.nix
index e69de29bb2..0f4a330f7f 100644
--- a/services/nixcon-demo/default.nix
+++ b/services/nixcon-demo/default.nix
@@ -0,0 +1,3 @@
+{ pkgs, ... }:
+
+pkgs.third_party.naersk.buildPackage ./. {}
diff --git a/services/tazblog/default.nix b/services/tazblog/default.nix
index 5dc3bdaf3e..2e75c3c2dc 100644
--- a/services/tazblog/default.nix
+++ b/services/tazblog/default.nix
@@ -2,9 +2,10 @@
 #
 # tazblog.nix was generated using cabal2nix.
 
-{ writeShellScriptBin, haskell }:
+{ pkgs, ... }:
 
 let
+  inherit (pkgs) writeShellScriptBin haskell;
   tazblog = haskell.packages.ghc865.callPackage ./tazblog.nix {};
   wrapper =  writeShellScriptBin "tazblog" ''
     export PORT=8000
diff --git a/third_party/naersk.nix b/third_party/naersk.nix
new file mode 100644
index 0000000000..c12c1abbbf
--- /dev/null
+++ b/third_party/naersk.nix
@@ -0,0 +1,9 @@
+{ pkgs, ... }:
+
+let inherit (pkgs) callPackage fetchFromGitHub;
+in callPackage (fetchFromGitHub {
+  owner = "nmattia";
+  repo = "naersk";
+  rev = "68c1c2b2b661913cdc5ecabea518dfdc4f449027";
+  sha256 = "1ll310pl44kdbwfslzwvg2v7khf1y0xkg2j5wcfia4k7sj6bcl28";
+}) {}
diff --git a/third_party/nixery.nix b/third_party/nixery.nix
index cb10e0b913..f778e5da13 100644
--- a/third_party/nixery.nix
+++ b/third_party/nixery.nix
@@ -1,6 +1,6 @@
 # Technically I suppose Nixery is not a third-party program, but it's
 # outside of this repository ...
-{ pkgs }:
+{ pkgs, ... }:
 
 let src = pkgs.fetchFromGitHub {
   owner = "google";
diff --git a/third_party/ormolu.nix b/third_party/ormolu.nix
new file mode 100644
index 0000000000..3175e25ff1
--- /dev/null
+++ b/third_party/ormolu.nix
@@ -0,0 +1,8 @@
+{ pkgs, ... }:
+
+import (pkgs.fetchFromGitHub {
+  owner = "tweag";
+  repo = "ormolu";
+  rev = "a7076c0f83e5c06ea9067b71171859fa2ba8afd9";
+  sha256 = "1p4n2ja4ciw3qfskn65ggpy37mvgf2sslxqmqn8s8jjarnqcyfny";
+}) { inherit pkgs; }
diff --git a/third_party/terraform-gcp.nix b/third_party/terraform-gcp.nix
new file mode 100644
index 0000000000..3332c12e41
--- /dev/null
+++ b/third_party/terraform-gcp.nix
@@ -0,0 +1,3 @@
+{ pkgs, ... }:
+
+pkgs.terraform_0_12.withPlugins(p: [ p.google p.google-beta ])
diff --git a/tools/bin/__dispatch.sh b/tools/bin/__dispatch.sh
index 20848bd511..c22b0339fd 100755
--- a/tools/bin/__dispatch.sh
+++ b/tools/bin/__dispatch.sh
@@ -11,19 +11,19 @@ readonly TARGET_TOOL=$(basename $0)
 
 case "${TARGET_TOOL}" in
   terraform)
-    attr="terraform-gcp"
+    attr="third_party.terraform-gcp"
     ;;
   kontemplate)
     attr="kontemplate"
     ;;
   blog_cli)
-    attr="tazjin.blog_cli"
+    attr="tools.blog_cli"
     ;;
   stern)
     attr="stern"
     ;;
   pass)
-    attr="tazjin.kms_pass"
+    attr="tools.kms_pass"
     ;;
   *)
     echo "The tool '${TARGET_TOOL}' is currently not installed in this repository."
diff --git a/tools/blog_cli/default.nix b/tools/blog_cli/default.nix
index c755d273a2..8113c93360 100644
--- a/tools/blog_cli/default.nix
+++ b/tools/blog_cli/default.nix
@@ -1,6 +1,6 @@
-{ buildGoPackage }:
+{ pkgs, ... }:
 
-buildGoPackage {
+pkgs.buildGoPackage {
   name = "blog_cli";
   goPackagePath = "github.com/tazjin/personal/blog_cli";
   src = ./.;
diff --git a/tools/kms_pass/default.nix b/tools/kms_pass/default.nix
index fbc17650a9..113db30224 100644
--- a/tools/kms_pass/default.nix
+++ b/tools/kms_pass/default.nix
@@ -6,10 +6,10 @@
 #
 # Only the 'show' and 'insert' commands are supported.
 
-{ google-cloud-sdk, tree, writeShellScriptBin
-, project, region, keyring, key }:
+{ pkgs, kms, ... }:
 
-writeShellScriptBin "pass" ''
+let inherit (pkgs) google-cloud-sdk tree writeShellScriptBin;
+in writeShellScriptBin "pass" ''
   set -eo pipefail
 
   CMD="$1"
@@ -34,20 +34,20 @@ writeShellScriptBin "pass" ''
     show)
       secret_check
       ${google-cloud-sdk}/bin/gcloud kms decrypt \
-        --project ${project} \
-        --location ${region} \
-        --keyring ${keyring} \
-        --key ${key} \
+        --project ${kms.project} \
+        --location ${kms.region} \
+        --keyring ${kms.keyring} \
+        --key ${kms.key} \
         --ciphertext-file $SECRET_PATH \
         --plaintext-file -
       ;;
     insert)
       secret_check
       ${google-cloud-sdk}/bin/gcloud kms encrypt \
-        --project ${project} \
-        --location ${region} \
-        --keyring ${keyring} \
-        --key ${key} \
+        --project ${kms.project} \
+        --location ${kms.region} \
+        --keyring ${kms.keyring} \
+        --key ${kms.key} \
         --ciphertext-file $SECRET_PATH \
         --plaintext-file -
       echo "Inserted secret '$SECRET'"