provider.go

// Mostly adapted from tfschema - https://github.com/minamijoyo/tfschema
package tfstructs

import (
	"fmt"
	log "github.com/sirupsen/logrus"
	"go/build"
	"io/ioutil"
	oldLog "log"
	"os"
	"os/exec"
	"path/filepath"
	"reflect"
	"runtime"
	"strings"

	internalPlugin "github.com/hashicorp/go-plugin"
	"github.com/hashicorp/terraform/plugin"
	"github.com/hashicorp/terraform/plugin/discovery"
	"github.com/hashicorp/terraform/providers"
	"github.com/hashicorp/terraform/provisioners"
	"github.com/mitchellh/go-homedir"
)

var internalProvisionerList = map[string]bool{
	"chef":            true,
	"file":            true,
	"habitat":         true,
	"local-exec":      true,
	"puppet":          true,
	"remote-exec":     true,
	"salt-masterless": true,
}

// Client represents a tfschema Client.
type Client struct {
	provider     *plugin.GRPCProvider
	provisioner  *plugin.GRPCProvisioner
	pluginClient interface{}
}

// NewProvisionerClient creates a new Client instance for Provisioner.
func NewProvisionerClient(name string, targetDir string) (*Client, error) {
	// find a provisioner plugin
	if !internalProvisionerList[name] {

		pluginMeta, err := findPlugin("provisioner", name, targetDir)
		if err != nil {
			return nil, err
		}
		pluginClient := plugin.Client(*pluginMeta)
		rpcClient, err2 := pluginClient.Client()
		if err2 != nil {
			return nil, fmt.Errorf("Failed to initialize plugin: %s", err2)
		}
		// create a new resource provisioner.
		raw, err := rpcClient.Dispense(plugin.ProvisionerPluginName)
		if err != nil {
			return nil, fmt.Errorf("Failed to dispense plugin: %s", err)
		}

		provisioner := raw.(*plugin.GRPCProvisioner)

		return &Client{
			provisioner:  provisioner,
			pluginClient: pluginClient,
		}, nil

	} else {
		// initialize a plugin Client.
		pluginClientConfig := plugin.ClientConfig(discovery.PluginMeta{
			Name: "terraform",
		})

		res, _ := exec.LookPath("terraform")
		pluginClientConfig.Cmd = exec.Command(res, "internal-plugin", "provisioner", name)

		pluginClient := internalPlugin.NewClient(pluginClientConfig)
		var err error
		rpcClient, err := pluginClient.Client()
		if err != nil {
			return nil, fmt.Errorf("Failed to initialize plugin: %s", err)
		}

		// create a new resource provisioner.
		raw, err := rpcClient.Dispense(plugin.ProvisionerPluginName)
		if err != nil {
			return nil, fmt.Errorf("Failed to dispense plugin: %s", err)
		}

		provisioner := raw.(*plugin.GRPCProvisioner)

		return &Client{
			provisioner:  provisioner,
			pluginClient: pluginClient,
		}, nil
	}
}

// NewClient creates a new Client instance.
func NewClient(providerName string, targetDir string) (*Client, error) {
	// find a provider plugin
	pluginMeta, err := findPlugin("provider", providerName, targetDir)
	if err != nil {
		return nil, err
	}

	clientName := fmt.Sprintf("%s_%s", pluginMeta.Name, pluginMeta.Version)
	// initialize a plugin Client.
	var finalClient *Client
	if Clients[clientName] == nil {
		pluginClient := plugin.Client(*pluginMeta)
		rpcClient, err := pluginClient.Client()
		if err != nil {
			return nil, fmt.Errorf("Failed to initialize plugin: %s", err)
		}

		// create a new resource provider.
		raw, err := rpcClient.Dispense(plugin.ProviderPluginName)
		if err != nil {
			return nil, fmt.Errorf("Failed to dispense plugin: %s", err)
		}

		provider := raw.(*plugin.GRPCProvider)
		finalClient = &Client{
			provider:     provider,
			pluginClient: pluginClient,
		}

		Clients[clientName] = finalClient
	} else {
		finalClient = Clients[clientName]
	}

	return finalClient, nil
}

// findPlugin finds a plugin with the name specified in the arguments.
func findPlugin(pluginType string, pluginName string, targetDir string) (*discovery.PluginMeta, error) {
	dirs, err := pluginDirs(targetDir)
	if err != nil {
		return nil, err
	}

	oldLog.SetOutput(ioutil.Discard)

	pluginMetaSet := discovery.FindPlugins(pluginType, dirs).WithName(pluginName)

	// if pluginMetaSet doesn't have any pluginMeta, pluginMetaSet.Newest() will call panic.
	// so check it here.
	if pluginMetaSet.Count() > 0 {
		ret := pluginMetaSet.Newest()
		return &ret, nil
	}

	return nil, fmt.Errorf("Failed to find plugin: %s. Plugin binary was not found in any of the following directories: [%s]", pluginName, strings.Join(dirs, ", "))
}

// pluginDirs returns a list of directories to find plugin.
// This is almost the same as Terraform, but not exactly the same.
func pluginDirs(targetDir string) ([]string, error) {
	dirs := []string{}

	// current directory
	dirs = append(dirs, ".")

	// same directory as this executable
	exePath, err := os.Executable()
	if err != nil {
		return []string{}, fmt.Errorf("Failed to get executable path: %s", err)
	}
	dirs = append(dirs, filepath.Dir(exePath))

	// user vendor directory
	arch := runtime.GOOS + "_" + runtime.GOARCH
	vendorDir := filepath.Join("terraform.d", "plugins", arch)
	dirs = append(dirs, vendorDir)

	// home dir will be searched afterward
	homeDir, err := homedir.Dir()
	if err != nil {
		return []string{}, fmt.Errorf("Failed to get home dir: %s", err)
	}

	// auto installed directory
	// This does not take into account overriding the data directory.
	autoInstalledDir := ""

	searchLevel := 4

	for dir := targetDir; dir != "" && searchLevel != 0; dir = filepath.Dir(dir) {

		log.Debug("[DEBUG] search .terraform dir in %s", dir)

		if _, err := os.Stat(filepath.Join(dir, ".terraform")); err == nil {
			autoInstalledDir = filepath.Join(dir, ".terraform", "plugins", arch)
			break
		}

		searchLevel -= 1
	}

	if autoInstalledDir != "" {
		dirs = append(dirs, autoInstalledDir)
	}

	// global plugin directory
	configDir := filepath.Join(homeDir, ".terraform.d", "plugins")
	dirs = append(dirs, configDir)
	dirs = append(dirs, filepath.Join(configDir, arch))

	// global plugin cache directory
	// This does not take into account overriding the plugin cache directory.
	cacheDir := filepath.Join(homeDir, ".terraform.d", "plugin-cache", arch)
	dirs = append(dirs, cacheDir)

	// GOPATH
	// This is not included in the Terraform, but for convenience.
	gopath := build.Default.GOPATH
	dirs = append(dirs, filepath.Join(gopath, "bin"))

	log.Debug("[DEBUG] plugin dirs: %#v", dirs)
	return dirs, nil
}

// GetRawProviderSchema returns a raw type definiton of provider schema.
func (c *Client) GetRawProviderSchema() (*providers.Schema, error) {

	res := c.provider.GetSchema()
	return &res.Provider, nil
}

// GetRawProvisionerSchema returns a raw type definiton of provisioner schema.
func (c *Client) GetRawProvisionerSchema() (*provisioners.GetSchemaResponse, error) {

	res := c.provisioner.GetSchema()
	return &res, nil
}

// GetRawResourceTypeSchema returns a type definiton of resource type.
func (c *Client) GetRawResourceTypeSchema(resourceType string) (*providers.Schema, error) {

	res := c.provider.GetSchema()
	if res.ResourceTypes[resourceType].Block == nil {
		return nil, fmt.Errorf("Failed to find resource type: %s", resourceType)
	}

	b := res.ResourceTypes[resourceType]
	return &b, nil
}

// GetResourceTypes returns a type definiton of resource type.
func (c *Client) GetResourceTypes() ([]string, error) {
	res := c.provider.GetSchema()
	var result []string

	for k, _ := range res.ResourceTypes {
		result = append(result, k)
	}
	return result, nil
}

// GetDataSourceTypes returns a type definiton of resource type.
func (c *Client) GetDataSourceTypes() ([]string, error) {
	res := c.provider.GetSchema()
	var result []string

	for k, _ := range res.DataSources {
		result = append(result, k)
	}
	return result, nil
}

// GetRawDataSourceTypeSchema returns a type definiton of resource type.
func (c *Client) GetRawDataSourceTypeSchema(dataSourceType string) (*providers.Schema, error) {

	res := c.provider.GetSchema()

	if res.DataSources[dataSourceType].Block == nil {
		return nil, fmt.Errorf("Failed to find data source type: %s", dataSourceType)
	}

	b := res.DataSources[dataSourceType]
	return &b, nil
}

// Kill kills a process of the plugin.
func (c *Client) Kill() {
	// We cannot import the vendor version of go-plugin using terraform.
	// So, we call (*go-plugin.Client).Kill() by reflection here.
	v := reflect.ValueOf(c.pluginClient).MethodByName("Kill")
	v.Call([]reflect.Value{})
}