caddy: withPlugins better error messages for untagged plugins (#368657)

nixos/doc/manual/release-notes/rl-2505.section.md

@@ -289,14 +289,22 @@
   services.caddy = {
     enable = true;
     package = pkgs.caddy.withPlugins {
-      plugins = [ "github.com/caddy-dns/powerdns@v1.0.1" ];
-      hash = "sha256-F/jqR4iEsklJFycTjSaW8B/V3iTGqqGOzwYBUXxRKrc=";
+      plugins = [
+        # tagged upstream
+        "github.com/caddy-dns/powerdns@v1.0.1"
+        # pseudo-version number generated by Go
+        "github.com/caddy-dns/cloudflare@v0.0.0-20240703190432-89f16b99c18e"
+        "github.com/mholt/caddy-webdav@v0.0.0-20241008162340-42168ba04c9d"
+      ];
+      hash = "sha256-wqXSd1Ep9TVpQi570TTb96LwzNYvWL5EBJXMJfYWCAk=";
     };
   };
   ```
 
   To get the necessary hash of the vendored dependencies, omit `hash`. The build will fail and tell you the correct value.
 
+  Note that all provided plugins must have versions/tags (string after `@`), even if upstream repo does not tag each release. For untagged plugins, you can either create an empty Go project and run `go get <plugin>` and see changes in `go.mod` to get the pseudo-version number, or provide a commit hash in place of version/tag for the first run, and update the plugin string based on the error output.
+
 - KDE Partition Manager `partitionmanager`'s support for ReiserFS is removed.
   ReiserFS has not been actively maintained for many years. It has been marked as obsolete since Linux 6.6, and
   [is removed](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c01f664e4ca210823b7594b50669bbd9b0a3c3b0)

nixos/tests/caddy.nix

@@ -3,12 +3,15 @@ import ./make-test-python.nix (
   {
     name = "caddy";
     meta = with pkgs.lib.maintainers; {
-      maintainers = [ Br1ght0ne ];
+      maintainers = [
+        Br1ght0ne
+        stepbrobd
+      ];
     };
 
     nodes = {
       webserver =
-        { pkgs, lib, ... }:
+        { pkgs, ... }:
         {
           services.caddy.enable = true;
           services.caddy.extraConfig = ''
@@ -63,6 +66,24 @@ import ./make-test-python.nix (
               respond "hello world"
             '';
           };
+          specialisation.with-plugins.configuration = {
+            services.caddy = {
+              package = pkgs.caddy.withPlugins {
+                plugins = [ "github.com/caddyserver/replace-response@v0.0.0-20241211194404-3865845790a7" ];
+                hash = "sha256-zgMdtOJbmtRSfTlrrg8njr11in2C7OAXLB+34V23jek=";
+              };
+              configFile = pkgs.writeText "Caddyfile" ''
+                {
+                  order replace after encode
+                }
+
+                localhost:80 {
+                  respond "hello world"
+                  replace world caddy
+                }
+              '';
+            };
+          };
         };
     };
 
@@ -73,6 +94,7 @@ import ./make-test-python.nix (
         justReloadSystem = "${nodes.webserver.system.build.toplevel}/specialisation/config-reload";
         multipleConfigs = "${nodes.webserver.system.build.toplevel}/specialisation/multiple-configs";
         rfc42Config = "${nodes.webserver.system.build.toplevel}/specialisation/rfc42";
+        withPluginsConfig = "${nodes.webserver.system.build.toplevel}/specialisation/with-plugins";
       in
       ''
         url = "http://localhost/example.html"
@@ -108,6 +130,13 @@ import ./make-test-python.nix (
             )
             webserver.wait_for_open_port(80)
             webserver.succeed("curl http://localhost | grep hello")
+
+        with subtest("plugins are correctled installed and configurable"):
+            webserver.succeed(
+                "${withPluginsConfig}/bin/switch-to-configuration test >&2"
+            )
+            webserver.wait_for_open_port(80)
+            webserver.succeed("curl http://localhost | grep caddy")
       '';
   }
 )

pkgs/by-name/ca/caddy/package.nix

@@ -7,10 +7,6 @@
 , testers
 , installShellFiles
 , stdenv
-, go
-, xcaddy
-, cacert
-, git
 }:
 let
   version = "2.8.4";

pkgs/by-name/ca/caddy/plugins.nix

@@ -1,3 +1,4 @@
+# callPackage args
 {
   lib,
   stdenv,
@@ -7,19 +8,44 @@
   git,
   caddy,
 }:
+
+let
+  inherit (builtins) hashString;
+  inherit (lib)
+    assertMsg
+    concatMapStrings
+    elemAt
+    fakeHash
+    filter
+    hasInfix
+    length
+    lessThan
+    sort
+    toShellVar
+    ;
+in
+
+# pkgs.caddy.withPlugins args
 {
   plugins,
-  hash ? lib.fakeHash,
+  hash ? fakeHash,
 }:
+
 let
-  pluginsSorted = lib.sort lib.lessThan plugins;
-  pluginsList = lib.concatMapStrings (plugin: "${plugin}-") pluginsSorted;
-  pluginsHash = builtins.hashString "md5" pluginsList;
-  pluginsWithoutVersion = lib.filter (p: !lib.hasInfix "@" p) pluginsSorted;
+  pluginsSorted = sort lessThan plugins;
+  pluginsList = concatMapStrings (plugin: "${plugin}-") pluginsSorted;
+  pluginsHash = hashString "md5" pluginsList;
+  pluginsWithoutVersion = filter (p: !hasInfix "@" p) pluginsSorted;
 in
-assert lib.assertMsg (
-  lib.length pluginsWithoutVersion == 0
-) "All plugins should have a version (eg ${lib.elemAt pluginsWithoutVersion 0}@x.y.z)!";
+
+# eval barrier: user provided plugins must have tags
+# the go module must either be tagged in upstream repo
+# or user must provide commit sha or a pseudo-version number
+# https://go.dev/doc/modules/version-numbers#pseudo-version-number
+assert assertMsg (
+  length pluginsWithoutVersion == 0
+) "Plugins must have tags present (e.g. ${elemAt pluginsWithoutVersion 0}@x.y.z)!";
+
 caddy.overrideAttrs (
   finalAttrs: prevAttrs: {
     vendorHash = null;
@@ -38,7 +64,7 @@ caddy.overrideAttrs (
       dontUnpack = true;
       buildPhase =
         let
-          withArgs = lib.concatMapStrings (plugin: "--with ${plugin} ") pluginsSorted;
+          withArgs = concatMapStrings (plugin: "--with ${plugin} ") pluginsSorted;
         in
         ''
           export GOCACHE=$TMPDIR/go-cache
@@ -55,11 +81,14 @@ caddy.overrideAttrs (
       outputHashAlgo = "sha256";
     };
 
+    # xcaddy built output always uses pseudo-version number
+    # we enforce user provided plugins are present and have matching tags here
     doInstallCheck = true;
     installCheckPhase = ''
       runHook preInstallCheck
 
-      ${lib.toShellVar "notfound" pluginsSorted}
+      ${toShellVar "notfound" pluginsSorted}
+
       while read kind module version; do
         [[ "$kind" = "dep" ]] || continue
         module="''${module}@''${version}"
@@ -69,8 +98,28 @@ caddy.overrideAttrs (
           fi
         done
       done < <($out/bin/caddy build-info)
+
       if (( ''${#notfound[@]} )); then
-        >&2 echo "Plugins not found: ''${notfound[@]}"
+        for plugin in "''${notfound[@]}"; do
+          base=''${plugin%@*}
+          specified=''${plugin#*@}
+          found=0
+
+          while read kind module expected; do
+            [[ "$kind" = "dep" && "$module" = "$base" ]] || continue
+            echo "Plugin \"$base\" have incorrect tag:"
+            echo "  specified: \"$base@$specified\""
+            echo "  got: \"$base@$expected\""
+            found=1
+          done < <($out/bin/caddy build-info)
+
+          if (( found == 0 )); then
+            echo "Plugin \"$base\" not found in build:"
+            echo "  specified: \"$base@$specified\""
+            echo "  plugin does not exist in the xcaddy build output, open an issue in nixpkgs or upstream"
+          fi
+        done
+
         exit 1
       fi