refactor: Get rid of nixpkgs dependency; parse env values in go, use …

…nixpkgs.lib

eval.nix

@@ -1,28 +1,24 @@
-with import <nixpkgs> { };
 with builtins;
 
 rec {
-  yaml2nix =
-    path:
-    let
-      jsonOutputDrv = runCommand "from-yaml" {
-        nativeBuildInputs = [ yq-go ];
-      } ''yq -M -o json . "${path}" > "$out"'';
-    in
-    fromJSON (readFile jsonOutputDrv);
+  # pin nixpkgs.lib
+  lib =
+    (builtins.getFlake "github:nix-community/nixpkgs.lib/4b620020fd73bdd5104e32c702e65b60b6869426").lib;
 
+  # Multiline secret values
   mlVals = val: ''
     {{ "${val}"|fetchSecretValue }}
   '';
+  # expand secret values
   vals = val: ''{{"${val}"|fetchSecretValue}}'';
 
   # render helmfile to object
   render =
-    state: env:
+    state: env: val:
     let
       hf = import /${state}/helmfile.nix;
       var = {
-        values = lib.mergeAttrs (yaml2nix /${state}/env/defaults.yaml) (yaml2nix /${state}/env/${env}.yaml);
+        values = fromJSON (readFile val);
         environment.name = env;
       };
     in

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"log"
 	"os"
@@ -161,12 +162,25 @@ func JSONToYAMLs(j []byte) ([]byte, error) {
 // Render the helmfile using the nix command.
 func renderHelmfile(base string, env string) ([]byte, error) {
 	f, err := writeEvalNix()
-	defer os.Remove(f.Name())
 	if err != nil {
 		log.Fatalf("Could not write eval.nix: %s", err)
 	}
-	expr := fmt.Sprintf("(import %s).render \"%s\" \"%s\"", f.Name(), base, env)
-	cmd := []string{"--extra-experimental-features", "nix-command", "eval", "--json", "--impure", "--expr", expr}
+	defer os.Remove(f.Name())
+	val, err := writeValJson(base)
+	if err != nil {
+		log.Fatalf("Could not write values.json: %s", err)
+	}
+	defer os.Remove(val.Name())
+	expr := fmt.Sprintf("(import %s).render \"%s\" \"%s\" \"%s\"", f.Name(), base, env, val.Name())
+	cmd := []string{
+		"--extra-experimental-features", "nix-command",
+		"--extra-experimental-features", "flakes",
+		"eval",
+		"-I", "nixpkgs=flake:github:nix-community/nixpkgs.lib",
+		"--json",
+		"--impure",
+		"--expr", expr,
+	}
 	eval := exec.Command("nix", cmd...)
 	l.Println("Running nix", strings.Join(cmd, " "))
 	eval.Stderr = os.Stderr
@@ -199,3 +213,39 @@ func writeEvalNix() (*os.File, error) {
 	}
 	return f, nil
 }
+
+func writeValJson(state string) (*os.File, error) {
+	f, err := os.CreateTemp("", "val.*.json")
+	if err != nil {
+		return nil, err
+	}
+	defaultVal, err := os.ReadFile(state + "/env/defaults.yaml")
+	if err != nil {
+		return nil, err
+	}
+	var m map[string]interface{}
+	err = yaml.Unmarshal(defaultVal, &m)
+	if err != nil {
+		return nil, err
+	}
+	envVal, err := os.ReadFile(state + "/env/" + opts.Env + ".yaml")
+	if err != nil {
+		return nil, err
+	}
+	err = yaml.Unmarshal(envVal, &m)
+	if err != nil {
+		return nil, err
+	}
+	envStr, err := json.Marshal(m)
+	if err != nil {
+		return nil, err
+	}
+	if _, err := f.Write(envStr); err != nil {
+		f.Close()
+		return nil, err
+	}
+	if err := f.Close(); err != nil {
+		return nil, err
+	}
+	return f, nil
+}