feat: enable checker go plugins

Signed-off-by: John Andersen <[email protected]>

checks/dynamic.go

@@ -0,0 +1,59 @@
+// Copyright 2024 OpenSSF Scorecard Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package checks
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"plugin"
+	"strings"
+)
+
+const CheckDynamicPluginLocationEnvironmentVariable = "SCORECARD_DYNAMIC_CHECKS"
+
+//nolint:gochecknoinits
+func init() {
+	pluginsDir, ok := os.LookupEnv(CheckDynamicPluginLocationEnvironmentVariable)
+	if !ok {
+		return
+	}
+
+	files, err := ioutil.ReadDir(pluginsDir)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, file := range files {
+		if !strings.HasSuffix(file.Name(), ".so") {
+			continue
+		}
+
+		p, err := plugin.Open(file.Name())
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		registerCheck, err := p.Lookup("RegisterCheck")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = registerCheck.(func() error)()
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}