From f2282398349aa74c8dc444508ec95aa4873a6cd7 Mon Sep 17 00:00:00 2001
From: Ingolf Wagner <contact@ingolf-wagner.de>
Date: Wed, 19 Jun 2024 14:57:53 +0200
Subject: [PATCH 1/2] add lib/facts.nix

---
 lib/facts.nix | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 lib/facts.nix

diff --git a/lib/facts.nix b/lib/facts.nix
new file mode 100644
index 00000000..6f19a6c1
--- /dev/null
+++ b/lib/facts.nix
@@ -0,0 +1,64 @@
+{ lib, machineDir, ... }:
+let
+
+  allMachineNames = lib.mapAttrsToList (name: _: name) (builtins.readDir machineDir);
+
+  getFactPath = fact: machine:
+    "${machineDir}/${machine}/facts/${fact}";
+
+  readFact = fact: machine:
+    let
+      path = getFactPath fact machine;
+    in
+    if builtins.pathExists path then
+      builtins.readFile path
+    else
+      null;
+
+  # Example:
+  #
+  # readFactFromAllMachines zerotier-ip
+  # => {
+  #   machineA = "1.2.3.4";
+  #   machineB = "5.6.7.8";
+  # };
+  readFactFromAllMachines = fact:
+    let
+      machines = allMachineNames;
+      facts = lib.genAttrs machines (readFact fact);
+      filteredFacts = lib.filterAttrs (_machine: fact: fact != null) facts;
+    in
+    filteredFacts;
+
+  # all given facts are are set and factvalues are never null.
+  #
+  # Example:
+  #
+  # readFactsFromAllMachines [ "zerotier-ip" "syncthing.pub" ]
+  # => {
+  #   machineA =
+  #     {
+  #       "zerotier-ip" = "1.2.3.4";
+  #       "synching.pub" = "1234";
+  #     };
+  #   machineB =
+  #     {
+  #       "zerotier-ip" = "5.6.7.8";
+  #       "synching.pub" = "23456719";
+  #     };
+  # };
+  readFactsFromAllMachines = facts:
+    let
+      # machine -> fact -> factvalue
+      machinesFactsAttrs = lib.genAttrs allMachineNames (machine: lib.genAttrs facts (fact: readFact fact machine));
+      # remove all machines which don't have all facts set
+      filteredMachineFactAttrs =
+        lib.filterAttrs (_machine: values: builtins.all (fact: values.${fact} != null) facts)
+          machinesFactsAttrs;
+    in
+    filteredMachineFactAttrs;
+
+
+
+in
+{ inherit allMachineNames getFactPath readFact readFactFromAllMachines readFactsFromAllMachines; }

From 1a969d884eedf5cffc57bb0563e049fa19bf67ff Mon Sep 17 00:00:00 2001
From: a-kenji <aks.kenji@protonmail.com>
Date: Tue, 2 Jul 2024 11:26:50 +0200
Subject: [PATCH 2/2] lib: add fact loaders to clan lib

---
 lib/default.nix |  3 ++-
 lib/facts.nix   | 42 +++++++++++++++++++++++++-----------------
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/lib/default.nix b/lib/default.nix
index 086fcce8..91a23d6d 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -6,8 +6,9 @@
 }:
 {
   evalClanModules = import ./eval-clan-modules { inherit clan-core nixpkgs lib; };
+  buildClan = import ./build-clan { inherit clan-core lib nixpkgs; };
+  facts = import ./facts.nix { inherit lib; };
   inventory = import ./inventory { inherit lib clan-core; };
   jsonschema = import ./jsonschema { inherit lib; };
   modules = import ./description.nix { inherit clan-core lib; };
-  buildClan = import ./build-clan { inherit clan-core lib nixpkgs; };
 }
diff --git a/lib/facts.nix b/lib/facts.nix
index 6f19a6c1..5ba36b5d 100644
--- a/lib/facts.nix
+++ b/lib/facts.nix
@@ -1,19 +1,17 @@
-{ lib, machineDir, ... }:
+{ lib, ... }:
+machineDir:
 let
 
   allMachineNames = lib.mapAttrsToList (name: _: name) (builtins.readDir machineDir);
 
-  getFactPath = fact: machine:
-    "${machineDir}/${machine}/facts/${fact}";
+  getFactPath = fact: machine: "${machineDir}/${machine}/facts/${fact}";
 
-  readFact = fact: machine:
+  readFact =
+    fact: machine:
     let
       path = getFactPath fact machine;
     in
-    if builtins.pathExists path then
-      builtins.readFile path
-    else
-      null;
+    if builtins.pathExists path then builtins.readFile path else null;
 
   # Example:
   #
@@ -22,7 +20,8 @@ let
   #   machineA = "1.2.3.4";
   #   machineB = "5.6.7.8";
   # };
-  readFactFromAllMachines = fact:
+  readFactFromAllMachines =
+    fact:
     let
       machines = allMachineNames;
       facts = lib.genAttrs machines (readFact fact);
@@ -47,18 +46,27 @@ let
   #       "synching.pub" = "23456719";
   #     };
   # };
-  readFactsFromAllMachines = facts:
+  readFactsFromAllMachines =
+    facts:
     let
       # machine -> fact -> factvalue
-      machinesFactsAttrs = lib.genAttrs allMachineNames (machine: lib.genAttrs facts (fact: readFact fact machine));
+      machinesFactsAttrs = lib.genAttrs allMachineNames (
+        machine: lib.genAttrs facts (fact: readFact fact machine)
+      );
       # remove all machines which don't have all facts set
-      filteredMachineFactAttrs =
-        lib.filterAttrs (_machine: values: builtins.all (fact: values.${fact} != null) facts)
-          machinesFactsAttrs;
+      filteredMachineFactAttrs = lib.filterAttrs (
+        _machine: values: builtins.all (fact: values.${fact} != null) facts
+      ) machinesFactsAttrs;
     in
     filteredMachineFactAttrs;
 
-
-
 in
-{ inherit allMachineNames getFactPath readFact readFactFromAllMachines readFactsFromAllMachines; }
+{
+  inherit
+    allMachineNames
+    getFactPath
+    readFact
+    readFactFromAllMachines
+    readFactsFromAllMachines
+    ;
+}