Add packer-plugin-check command (#10351)

cmd/packer-plugin-check/main.go

@@ -0,0 +1,177 @@
+// packer-plugin-check is a command used by plugins to validate compatibility and basic configuration
+// to work with Packer.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	packersdk "github.com/hashicorp/packer/packer-plugin-sdk/packer"
+	"github.com/hashicorp/packer/packer/plugin"
+)
+
+const packerPluginCheck = "packer-plugin-check"
+
+var (
+	docs = flag.Bool("docs", false, "flag to indicate that documentation files should be checked.")
+	load = flag.String("load", "", "flag to check if plugin can be loaded by Packer and is compatible with HCL2.")
+)
+
+// Usage is a replacement usage function for the flags package.
+func Usage() {
+	fmt.Fprintf(os.Stderr, "Usage of "+packerPluginCheck+":\n")
+	fmt.Fprintf(os.Stderr, "\t"+packerPluginCheck+" [flags]\n")
+	fmt.Fprintf(os.Stderr, "Flags:\n")
+	flag.PrintDefaults()
+}
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix(packerPluginCheck + ": ")
+	flag.Usage = Usage
+	flag.Parse()
+
+	if flag.NFlag() == 0 {
+		flag.Usage()
+		os.Exit(2)
+	}
+
+	if *docs {
+		if err := checkDocumentation(); err != nil {
+			fmt.Printf(err.Error())
+			os.Exit(2)
+		}
+		fmt.Printf("Plugin succesfully passed docs check.\n")
+	}
+
+	if len(*load) > 0 {
+		if err := checkPluginName(*load); err != nil {
+			fmt.Printf(err.Error())
+			os.Exit(2)
+		}
+		if err := discoverAndLoad(); err != nil {
+			fmt.Printf(err.Error())
+			os.Exit(2)
+		}
+		fmt.Printf("Plugin succesfully passed compatibility check.\n")
+	}
+}
+
+// checkDocumentation looks for the presence of a docs folder with mdx files inside.
+// It is not possible to predict the number of mdx files for a given plugin.
+// Because of that, finding one file inside the folder is enough to validate the docs existence.
+func checkDocumentation() error {
+	// TODO: this should be updated once we have defined what's going to be for plguin's docs
+	wd, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+
+	docsDir := wd + "/docs"
+	stat, err := os.Stat(docsDir)
+	if err != nil {
+		return fmt.Errorf("could not find docs folter: %s", err.Error())
+	}
+	if !stat.IsDir() {
+		return fmt.Errorf("expecting docs do be a directory of mdx files")
+	}
+
+	var mdxFound bool
+	_ = filepath.Walk(docsDir, func(path string, info os.FileInfo, err error) error {
+		if !info.IsDir() && filepath.Ext(path) == ".mdx" {
+			mdxFound = true
+			return io.EOF
+		}
+		return nil
+	})
+
+	if mdxFound {
+		fmt.Printf("a mdx file was found inside the docs folder\n")
+		return nil
+	}
+	return fmt.Errorf("no docs files found, make sure to have the docs in place before releasing")
+}
+
+// checkPluginName checks for the possible valid names for a plugin, packer-plugin-* or packer-[builder|provisioner|post-processor]-*.
+// If the name is prefixed with `packer-[builder|provisioner|post-processor]-`, packer won't be able to install it,
+// therefore a WARNING will be shown.
+func checkPluginName(name string) error {
+	if strings.HasPrefix(name, "packer-plugin-") {
+		return nil
+	}
+	if strings.HasPrefix(name, "packer-builder-") ||
+		strings.HasPrefix(name, "packer-provisioner-") ||
+		strings.HasPrefix(name, "packer-post-processor-") {
+		fmt.Printf("\n[WARNING] Plugin is named with old prefix `packer-[builder|provisioner|post-processor]-{name})`. " +
+			"These will be detected but Packer cannot install them automatically. " +
+			"The plugin must be a multi-plugin named packer-plugin-{name} to be installable through the `packer init` command.\n")
+		return nil
+	}
+	return fmt.Errorf("plugin's name is not valid")
+}
+
+// discoverAndLoad will discover the plugin binary from the current directory and load any builder/provisioner/post-processor
+// in the plugin configuration. At least one builder, provisioner, or post-processor should be found to validate the plugin's
+// compatibility with Packer.
+func discoverAndLoad() error {
+	config := plugin.Config{
+		PluginMinPort: 10000,
+		PluginMaxPort: 25000,
+	}
+	err := config.Discover()
+	if err != nil {
+		return err
+	}
+
+	// TODO: validate correctness of plugins loaded by checking them against the output of the `describe` command.
+	builders, provisioners, postProcessors := config.GetPlugins()
+	if len(builders) == 0 &&
+		len(provisioners) == 0 &&
+		len(postProcessors) == 0 {
+		return fmt.Errorf("couldn't load any Builder/Provisioner/Post-Processor from the plugin binary")
+	}
+
+	return checkHCL2ConfigSpec(builders, provisioners, postProcessors)
+}
+
+// checkHCL2ConfigSpec checks if the hcl2spec config is present for the given plugins by validating that ConfigSpec() does not
+// return an empty map of specs.
+func checkHCL2ConfigSpec(builders packersdk.MapOfBuilder, provisioners packersdk.MapOfProvisioner, postProcessors packersdk.MapOfPostProcessor) error {
+	var errs *packersdk.MultiError
+	for _, b := range builders.List() {
+		builder, err := builders.Start(b)
+		if err != nil {
+			return packersdk.MultiErrorAppend(err, errs)
+		}
+		if len(builder.ConfigSpec()) == 0 {
+			errs = packersdk.MultiErrorAppend(fmt.Errorf("builder %q does not contain the required hcl2spec configuration", b), errs)
+		}
+	}
+	for _, p := range provisioners.List() {
+		provisioner, err := provisioners.Start(p)
+		if err != nil {
+			return packersdk.MultiErrorAppend(err, errs)
+		}
+		if len(provisioner.ConfigSpec()) == 0 {
+			errs = packersdk.MultiErrorAppend(fmt.Errorf("provisioner %q does not contain the required hcl2spec configuration", p), errs)
+		}
+	}
+	for _, pp := range postProcessors.List() {
+		postProcessor, err := postProcessors.Start(pp)
+		if err != nil {
+			return packersdk.MultiErrorAppend(err, errs)
+		}
+		if len(postProcessor.ConfigSpec()) == 0 {
+			errs = packersdk.MultiErrorAppend(fmt.Errorf("post-processor %q does not contain the required hcl2spec configuration", pp), errs)
+		}
+	}
+	if errs != nil && len(errs.Errors) > 0 {
+		return errs
+	}
+	return nil
+}