default-validator: provide external plugin version.

Provide an externally comilable standalone version of the
default validator plugin. In addition to an illustrative
purpose, this provides an easier way of experimenting and
developing new validation features. Instead of having to
recompile the runtime, one can simply modify and run the
externally compiled version.

Signed-off-by: Krisztian Litkey <[email protected]>

Author: klihub

Makefile

@@ -56,6 +56,7 @@ PLUGINS := \
 	$(BIN_PATH)/ulimit-adjuster \
 	$(BIN_PATH)/v010-adapter \
 	$(BIN_PATH)/template \
+	$(BIN_PATH)/default-validator \
 	$(BIN_PATH)/wasm
 
 
@@ -134,6 +135,11 @@ $(BIN_PATH)/template: $(wildcard plugins/template/*.go)
 	$(Q)echo "Building $@..."; \
 	cd $(dir $<) && $(GO_BUILD) -o $@ .
 
+$(BIN_PATH)/default-validator: $(wildcard plugins/default-validator/external/*.go) $(wildcard plugins/default-validator/*.go)
+	$(Q)echo "Building $@..."; \
+	cd $(dir $<) && $(GO_BUILD) -o $@ .
+
+
 ifneq ($(TINYGO_DOCKER),1)
 $(BIN_PATH)/wasm: $(wildcard plugins/wasm/*.go)
 	$(Q)echo "Building $@..."; \

plugins/default-validator/external/plugin.go

@@ -0,0 +1,117 @@
+/*
+   Copyright The containerd 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 main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/sirupsen/logrus"
+	"gopkg.in/yaml.v3"
+
+	"github.com/containerd/nri/pkg/stub"
+	validator "github.com/containerd/nri/plugins/default-validator"
+)
+
+type plugin struct {
+	*validator.DefaultValidator
+	stub stub.Stub
+}
+
+var (
+	log *logrus.Logger
+)
+
+func (p *plugin) Configure(_ context.Context, config, _, _ string) (stub.EventMask, error) {
+	if config == "" {
+		log.Infof("No configuration provided, using defaults...")
+		return 0, nil
+	}
+
+	cfg := &validator.DefaultValidatorConfig{}
+	err := yaml.Unmarshal([]byte(config), cfg)
+	if err != nil {
+		return 0, fmt.Errorf("failed to parse configuration: %w", err)
+	}
+
+	if !cfg.Enable {
+		log.Infof("Validation disabled, exiting....")
+		os.Exit(0)
+	}
+
+	log.Infof("Using configuration %+v...", cfg)
+	p.SetConfig(cfg)
+
+	return 0, nil
+}
+
+func (p *plugin) onClose() {
+	log.Infof("Connection to the runtime lost, exiting...")
+	os.Exit(0)
+}
+
+func main() {
+	var (
+		pluginName string
+		pluginIdx  string
+		verbose    bool
+		err        error
+	)
+
+	log = logrus.StandardLogger()
+	log.SetFormatter(&logrus.TextFormatter{
+		PadLevelText: true,
+	})
+
+	flag.StringVar(&pluginName, "name", "", "plugin name to register to NRI")
+	flag.StringVar(&pluginIdx, "idx", "", "plugin index to register to NRI")
+	flag.BoolVar(&verbose, "verbose", false, "use verbose (debug) logging")
+	flag.Parse()
+
+	if verbose {
+		log.SetLevel(logrus.DebugLevel)
+	}
+
+	p := &plugin{
+		DefaultValidator: validator.NewDefaultValidator(
+			&validator.DefaultValidatorConfig{
+				Enable: true,
+			},
+		),
+	}
+
+	opts := []stub.Option{
+		stub.WithOnClose(p.onClose),
+	}
+	if pluginName != "" {
+		opts = append(opts, stub.WithPluginName(pluginName))
+	}
+	if pluginIdx != "" {
+		opts = append(opts, stub.WithPluginIdx(pluginIdx))
+	}
+
+	if p.stub, err = stub.New(p, opts...); err != nil {
+		log.Fatalf("failed to create plugin stub: %v", err)
+	}
+
+	if err = p.stub.Run(context.Background()); err != nil {
+		log.Errorf("plugin exited (%v)", err)
+		os.Exit(1)
+	}
+}