config.go

// Copyright 2023 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 config

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"os"

	"github.com/creasty/defaults"
	"sigs.k8s.io/yaml"

	"github.com/pipe-cd/pipecd/pkg/model"
)

const (
	SharedConfigurationDirName = ".pipe"
	versionV1Beta1             = "pipecd.dev/v1beta1"
)

// Kind represents the kind of configuration the data contains.
type Kind string

const (
	// KindKubernetesApp represents application configuration for a Kubernetes application.
	// This application can be a group of plain-YAML Kubernetes manifests,
	// or kustomization manifests or helm manifests.
	KindKubernetesApp Kind = "KubernetesApp"
	// KindTerraformApp represents application configuration for a Terraform application.
	// This application contains a single workspace of a terraform root module.
	KindTerraformApp Kind = "TerraformApp"
	// KindLambdaApp represents application configuration for an AWS Lambda application.
	KindLambdaApp Kind = "LambdaApp"
	// KindCloudRunApp represents application configuration for a CloudRun application.
	KindCloudRunApp Kind = "CloudRunApp"
	// KindECSApp represents application configuration for an AWS ECS.
	KindECSApp Kind = "ECSApp"
)

const (
	// KindPiped represents configuration for piped.
	// This configuration will be loaded while the piped is starting up.
	KindPiped Kind = "Piped"
	// KindControlPlane represents configuration for control plane's services.
	KindControlPlane Kind = "ControlPlane"
	// KindAnalysisTemplate represents shared analysis template for a repository.
	// This configuration file should be placed in .pipe directory
	// at the root of the repository.
	KindAnalysisTemplate Kind = "AnalysisTemplate"
	// KindEventWatcher represents configuration for Event Watcher.
	KindEventWatcher Kind = "EventWatcher"
)

var (
	ErrNotFound = errors.New("not found")
)

// Config represents configuration data load from file.
// The spec is depend on the kind of configuration.
type Config struct {
	Kind       Kind
	APIVersion string
	spec       interface{}

	KubernetesApplicationSpec *KubernetesApplicationSpec
	TerraformApplicationSpec  *TerraformApplicationSpec
	CloudRunApplicationSpec   *CloudRunApplicationSpec
	LambdaApplicationSpec     *LambdaApplicationSpec
	ECSApplicationSpec        *ECSApplicationSpec

	PipedSpec            *PipedSpec
	ControlPlaneSpec     *ControlPlaneSpec
	AnalysisTemplateSpec *AnalysisTemplateSpec
	EventWatcherSpec     *EventWatcherSpec
}

type genericConfig struct {
	Kind       Kind            `json:"kind"`
	APIVersion string          `json:"apiVersion,omitempty"`
	Spec       json.RawMessage `json:"spec"`
}

func (c *Config) init(kind Kind, apiVersion string) error {
	c.Kind = kind
	c.APIVersion = apiVersion

	switch kind {
	case KindKubernetesApp:
		c.KubernetesApplicationSpec = &KubernetesApplicationSpec{}
		c.spec = c.KubernetesApplicationSpec

	case KindTerraformApp:
		c.TerraformApplicationSpec = &TerraformApplicationSpec{}
		c.spec = c.TerraformApplicationSpec

	case KindCloudRunApp:
		c.CloudRunApplicationSpec = &CloudRunApplicationSpec{}
		c.spec = c.CloudRunApplicationSpec

	case KindLambdaApp:
		c.LambdaApplicationSpec = &LambdaApplicationSpec{}
		c.spec = c.LambdaApplicationSpec

	case KindECSApp:
		c.ECSApplicationSpec = &ECSApplicationSpec{}
		c.spec = c.ECSApplicationSpec

	case KindPiped:
		c.PipedSpec = &PipedSpec{}
		c.spec = c.PipedSpec

	case KindControlPlane:
		c.ControlPlaneSpec = &ControlPlaneSpec{}
		c.spec = c.ControlPlaneSpec

	case KindAnalysisTemplate:
		c.AnalysisTemplateSpec = &AnalysisTemplateSpec{}
		c.spec = c.AnalysisTemplateSpec

	case KindEventWatcher:
		c.EventWatcherSpec = &EventWatcherSpec{}
		c.spec = c.EventWatcherSpec

	default:
		return fmt.Errorf("unsupported kind: %s", c.Kind)
	}
	return nil
}

// UnmarshalJSON customizes the way to unmarshal json data into Config struct.
// Firstly, this unmarshal to a generic config and then unmarshal the spec
// which depend on the kind of configuration.
func (c *Config) UnmarshalJSON(data []byte) error {
	var (
		err error
		gc  = genericConfig{}
	)
	dec := json.NewDecoder(bytes.NewReader(data))
	dec.DisallowUnknownFields()
	if err := dec.Decode(&gc); err != nil {
		return err
	}
	if err = c.init(gc.Kind, gc.APIVersion); err != nil {
		return err
	}

	if len(gc.Spec) > 0 {
		dec := json.NewDecoder(bytes.NewReader(gc.Spec))
		dec.DisallowUnknownFields()
		err = dec.Decode(c.spec)
	}
	return err
}

type validator interface {
	Validate() error
}

// Validate validates the value of all fields.
func (c *Config) Validate() error {
	if c.APIVersion != versionV1Beta1 {
		return fmt.Errorf("unsupported version: %s", c.APIVersion)
	}
	if c.Kind == "" {
		return fmt.Errorf("kind is required")
	}
	if c.spec == nil {
		return fmt.Errorf("spec is required")
	}

	spec, ok := c.spec.(validator)
	if !ok {
		return fmt.Errorf("spec must have Validate function")
	}
	if err := spec.Validate(); err != nil {
		return err
	}
	return nil
}

// LoadFromYAML reads and decodes a yaml file to construct the Config.
func LoadFromYAML(file string) (*Config, error) {
	data, err := os.ReadFile(file)
	if err != nil {
		return nil, err
	}
	return DecodeYAML(data)
}

// DecodeYAML unmarshals config YAML data to config struct.
// It also validates the configuration after decoding.
func DecodeYAML(data []byte) (*Config, error) {
	js, err := yaml.YAMLToJSON(data)
	if err != nil {
		return nil, err
	}
	c := &Config{}
	if err := json.Unmarshal(js, c); err != nil {
		return nil, err
	}
	if err := defaults.Set(c); err != nil {
		return nil, err
	}
	if err := c.Validate(); err != nil {
		return nil, err
	}
	return c, nil
}

// ToApplicationKind converts configuration kind to application kind.
func (k Kind) ToApplicationKind() (model.ApplicationKind, bool) {
	switch k {
	case KindKubernetesApp:
		return model.ApplicationKind_KUBERNETES, true
	case KindTerraformApp:
		return model.ApplicationKind_TERRAFORM, true
	case KindLambdaApp:
		return model.ApplicationKind_LAMBDA, true
	case KindCloudRunApp:
		return model.ApplicationKind_CLOUDRUN, true
	case KindECSApp:
		return model.ApplicationKind_ECS, true
	}
	return model.ApplicationKind_KUBERNETES, false
}

func (c *Config) GetGenericApplication() (GenericApplicationSpec, bool) {
	switch c.Kind {
	case KindKubernetesApp:
		return c.KubernetesApplicationSpec.GenericApplicationSpec, true
	case KindTerraformApp:
		return c.TerraformApplicationSpec.GenericApplicationSpec, true
	case KindCloudRunApp:
		return c.CloudRunApplicationSpec.GenericApplicationSpec, true
	case KindLambdaApp:
		return c.LambdaApplicationSpec.GenericApplicationSpec, true
	case KindECSApp:
		return c.ECSApplicationSpec.GenericApplicationSpec, true
	}
	return GenericApplicationSpec{}, false
}