Add plugin registry

Signed-off-by: Yoshiki Fujikane <[email protected]>

pkg/plugin/registry/registry.go

@@ -0,0 +1,141 @@
+// Copyright 2024 The PipeCD 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 planner provides a piped component
+// that decides the deployment pipeline of a deployment.
+// The planner bases on the changes from git commits
+// then builds the deployment manifests to know the behavior of the deployment.
+// From that behavior the planner can decides which pipeline should be applied.
+package registry
+
+import (
+	"context"
+	"fmt"
+
+	config "github.com/pipe-cd/pipecd/pkg/configv1"
+	pluginapi "github.com/pipe-cd/pipecd/pkg/plugin/api/v1alpha1"
+	"github.com/pipe-cd/pipecd/pkg/plugin/api/v1alpha1/deployment"
+)
+
+// Plugin represents a plugin with its name and client.
+type Plugin struct {
+	Name string
+	Cli  pluginapi.PluginClient
+}
+
+// PluginRegistry is the interface that provides methods to get plugin clients.
+type PluginRegistry interface {
+	GetPluginClientByStageName(name string) (pluginapi.PluginClient, error)
+	GetPluginClientsByAppConfig(cfg *config.GenericApplicationSpec) ([]pluginapi.PluginClient, error)
+}
+
+type pluginRegistry struct {
+	nameBasedPlugins  map[string]pluginapi.PluginClient // key: plugin name
+	stageBasedPlugins map[string]pluginapi.PluginClient // key: stage name
+
+	// TODO: add more fields if needed (e.g. deploymentBasedPlugins, livestateBasedPlugins)
+}
+
+// NewPluginRegistry creates a new PluginRegistry based on the given plugins.
+func NewPluginRegistry(ctx context.Context, plugins []Plugin) (PluginRegistry, error) {
+	nameBasedPlugins := make(map[string]pluginapi.PluginClient)
+	stageBasedPlugins := make(map[string]pluginapi.PluginClient)
+
+	for _, plg := range plugins {
+		// add the plugin to the name-based plugins
+		nameBasedPlugins[plg.Name] = plg.Cli
+
+		// add the plugin to the stage-based plugins
+		res, err := plg.Cli.FetchDefinedStages(ctx, &deployment.FetchDefinedStagesRequest{})
+		if err != nil {
+			return nil, err
+		}
+
+		for _, stage := range res.Stages {
+			stageBasedPlugins[stage] = plg.Cli
+		}
+	}
+
+	return &pluginRegistry{
+		nameBasedPlugins:  nameBasedPlugins,
+		stageBasedPlugins: stageBasedPlugins,
+	}, nil
+}
+
+// GetPluginClientByStageName returns the plugin client based on the given stage name.
+func (pr *pluginRegistry) GetPluginClientByStageName(name string) (pluginapi.PluginClient, error) {
+	plugin, ok := pr.stageBasedPlugins[name]
+	if !ok {
+		return nil, fmt.Errorf("no plugin found for the specified stage")
+	}
+
+	return plugin, nil
+}
+
+// GetPluginClientsByAppConfig returns the plugin clients based on the given configuration.
+// The priority of determining plugins is as follows:
+//  1. If the pipeline is specified, it will determine the plugins based on the pipeline stages.
+//  2. If the plugins are specified, it will determine the plugins based on the plugin names.
+//  3. If neither the pipeline nor the plugins are specified, it will return an error.
+func (pr *pluginRegistry) GetPluginClientsByAppConfig(cfg *config.GenericApplicationSpec) ([]pluginapi.PluginClient, error) {
+	if cfg.Pipeline != nil && len(cfg.Pipeline.Stages) > 0 {
+		return pr.getPluginClientsByPipeline(cfg.Pipeline)
+	}
+
+	if cfg.Plugins != nil {
+		return pr.getPluginClientsByNames(cfg.Plugins)
+	}
+
+	return nil, fmt.Errorf("no plugin specified")
+}
+
+func (pr *pluginRegistry) getPluginClientsByPipeline(pipeline *config.DeploymentPipeline) ([]pluginapi.PluginClient, error) {
+	if len(pipeline.Stages) == 0 {
+		return nil, fmt.Errorf("no stages are set in the pipeline")
+	}
+
+	plugins := make([]pluginapi.PluginClient, 0, len(pipeline.Stages))
+	for _, stage := range pipeline.Stages {
+		plugin, ok := pr.stageBasedPlugins[stage.Name.String()]
+		if ok {
+			plugins = append(plugins, plugin)
+		}
+	}
+
+	if len(plugins) == 0 {
+		return nil, fmt.Errorf("no plugin found for each stages")
+	}
+
+	return plugins, nil
+}
+
+func (pr *pluginRegistry) getPluginClientsByNames(names []string) ([]pluginapi.PluginClient, error) {
+	if len(names) == 0 {
+		return nil, fmt.Errorf("no plugin names are set")
+	}
+
+	plugins := make([]pluginapi.PluginClient, 0, len(names))
+	for _, name := range names {
+		plugin, ok := pr.nameBasedPlugins[name]
+		if ok {
+			plugins = append(plugins, plugin)
+		}
+	}
+
+	if len(plugins) == 0 {
+		return nil, fmt.Errorf("no plugin found for the given plugin names")
+	}
+
+	return plugins, nil
+}