Package Kubenix script (#62)

* Package Kubenix script

* Update changelog

* Fix hardcoded kubeconfig

* Expose generated manifest with Kubenix CLI derivation passthru

pkgs/kubenix.nix

@@ -2,8 +2,11 @@
 , vals
 , colordiff
 , evalModules
-, runCommand
 , writeShellScript
+, writeScriptBin
+, makeWrapper
+, symlinkJoin
+, lib
 , module ? { }
 , specialArgs ? { }
 }:
@@ -11,9 +14,7 @@ let
   kubernetes = (evalModules {
     inherit module specialArgs;
   }).config.kubernetes or { };
-in
-runCommand "kubenix"
-{
+
   kubeconfig = kubernetes.kubeconfig or "";
   result = kubernetes.result or "";
 
@@ -21,75 +22,25 @@ runCommand "kubenix"
   # as workaround, we write to a script and call that
   # https://github.com/kubernetes/kubernetes/pull/108199#issuecomment-1058405404
   diff = writeShellScript "kubenix-diff" ''
-    ${colordiff}/bin/colordiff --nobanner -N -u -I ' kubenix/hash: ' -I ' generation: ' $@
+    ${lib.getExe colordiff} --nobanner -N -u -I ' kubenix/hash: ' -I ' generation: ' $@
   '';
-} ''
-  set -euo pipefail
-  mkdir -p $out/bin
 
-  # write the manifests for use with `nix build`
-  ln -s $result $out/manifest.json
+  script = (writeScriptBin "kubenix" (builtins.readFile ./kubenix.sh)).overrideAttrs (old: {
+    buildCommand = "${old.buildCommand}\npatchShebangs $out";
+  });
+in
+symlinkJoin {
+  name = "kubenix";
+  paths = [ script vals kubectl ];
+  buildInputs = [ makeWrapper ];
+  passthru.manifest = result;
 
-  # create a script for `nix run`
-  cat <<EOF> $out/bin/kubenix
-    set -uo pipefail
-
-    export KUBECONFIG=$kubeconfig
-    export KUBECTL_EXTERNAL_DIFF=$diff
-
-    function _help() {
-      echo "
-      kubenix - Kubernetes management with Nix
-
-      commands:
-        ""          - run diff, prompt for confirmation, then apply
-        apply       - create resources in target cluster
-        diff        - show a diff between configured and live resources
-        render      - print resource manifests to stdout
-
-      options:
-        -h --help   - show this menu
-      "
-    }
-
-    function _kubectl() {
-      ${vals}/bin/vals eval -fail-on-missing-key-in-map < $result | ${kubectl}/bin/kubectl \$@
-    }
-
-    # if no args given, add empty string
-    [ \$# -eq 0 ] && set -- ""
-
-    # parse arguments
-    while test \$# -gt 0; do
-      case "\$1" in
-
-        -h|--help)
-          _help
-        exit 0;;
-
-        "")
-          _kubectl diff -f - --prune
-          if [[ "\$?" -eq 1 ]]; then
-            read -p 'apply? [y/N]: ' response
-            [[ \$response == "y" ]] && _kubectl apply -f - --prune --all
-          fi
-         shift;;
-
-        render)
-          ${vals}/bin/vals eval < $result
-        shift;;
-
-        apply|diff)
-          _kubectl \$@ -f - --prune
-        shift;;
-
-        *)
-          _kubectl \$@
-        shift;;
-
-      esac
-    done
-
-  EOF
-  chmod +x $out/bin/kubenix
-''
+  postBuild = ''
+    export DIFF="${diff}"
+    wrapProgram $out/bin/kubenix \
+      --set PATH "$out/bin" \
+      --set KUBECONFIG "${kubeconfig}" \
+      --set KUBECTL_EXTERNAL_DIFF "''${DIFF}" \
+      --set MANIFEST "${result}"
+  '';
+}