Dynamic and context-driven Infrakit CLI (#544)

Signed-off-by: David Chung <david.chung@docker.com>

Author: David Chung

cmd/infrakit/base/output.go

@@ -1,34 +1,19 @@
 package base
 
 import (
-	"fmt"
 	"io/ioutil"
 	"os"
-	"path"
-	"strconv"
-	"strings"
 
 	"github.com/docker/infrakit/pkg/cli"
 	"github.com/docker/infrakit/pkg/discovery"
-	"github.com/docker/infrakit/pkg/template"
-	"github.com/ghodss/yaml"
 	"github.com/spf13/pflag"
 )
 
-// ProcessTemplateFunc is the function that processes the template at url and returns view or error.
-type ProcessTemplateFunc func(url string) (rendered string, err error)
-
-// ToJSONFunc converts the input buffer to json format
-type ToJSONFunc func(in []byte) (json []byte, err error)
-
-// FromJSONFunc converts json formatted input to output buffer
-type FromJSONFunc func(json []byte) (out []byte, err error)
-
 // ReadFromStdinIfElse checks condition and reads from stdin if true; otherwise it executes other.
 func ReadFromStdinIfElse(
 	condition func() bool,
 	otherwise func() (string, error),
-	toJSON ToJSONFunc) (rendered string, err error) {
+	toJSON cli.ToJSONFunc) (rendered string, err error) {
 
 	if condition() {
 		buff, err := ioutil.ReadAll(os.Stdin)
@@ -52,111 +37,10 @@ func ReadFromStdinIfElse(
 }
 
 // TemplateProcessor returns a flagset and a function for processing template input.
-func TemplateProcessor(plugins func() discovery.Plugins) (*pflag.FlagSet, ToJSONFunc, FromJSONFunc, ProcessTemplateFunc) {
-
-	fs := pflag.NewFlagSet("template", pflag.ExitOnError)
-
-	globals := fs.StringSliceP("var", "v", []string{}, "key=value pairs of globally scoped variagbles")
-	yamlDoc := fs.BoolP("yaml", "y", false, "True if input is in yaml format; json is the default")
-	dump := fs.BoolP("dump", "x", false, "True to dump to output instead of executing")
-	singlePass := fs.BoolP("final", "f", false, "True to render template as the final pass")
-
-	return fs,
-		// ToJSONFunc
-		func(in []byte) (json []byte, err error) {
-
-			defer func() {
-
-				if *dump {
-					fmt.Println("Raw:")
-					fmt.Println(string(in))
-					fmt.Println("Converted")
-					fmt.Println(string(json))
-					os.Exit(0) // special for debugging
-				}
-			}()
-
-			if *yamlDoc {
-				json, err = yaml.YAMLToJSON(in)
-				return
-			}
-			json = in
-			return
-
-		},
-		// FromJSONFunc
-		func(json []byte) (out []byte, err error) {
-
-			defer func() {
-
-				if *dump {
-					fmt.Println("Raw:")
-					fmt.Println(string(json))
-					fmt.Println("Converted")
-					fmt.Println(string(out))
-					os.Exit(0) // special for debugging
-				}
-			}()
-
-			if *yamlDoc {
-				out, err = yaml.JSONToYAML(json)
-				return
-			}
-			out = json
-			return
-
-		},
-		// ProcessTemplateFunc
-		func(url string) (view string, err error) {
-
-			if !strings.Contains(url, "://") {
-				p := url
-				if dir, err := os.Getwd(); err == nil {
-					p = path.Join(dir, url)
-				}
-				url = "file://" + p
-			}
-
-			log.Debug("reading template", "url", url)
-			engine, err := template.NewTemplate(url, template.Options{MultiPass: !*singlePass})
-			if err != nil {
-				return
-			}
-
-			for _, global := range *globals {
-				kv := strings.SplitN(global, "=", 2)
-				if len(kv) != 2 {
-					log.Warn("bad format kv", "input", global)
-					continue
-				}
-				key := strings.TrimSpace(kv[0])
-				val := strings.TrimSpace(kv[1])
-				if key != "" && val != "" {
-					// Attempt to convert to int and bool types so that template operations
-					// are not only against strings.
-					if intVal, err := strconv.Atoi(val); err == nil {
-						engine.Global(key, intVal)
-					} else if boolVar, err := strconv.ParseBool(val); err == nil {
-						engine.Global(key, boolVar)
-					} else {
-						engine.Global(key, val)
-					}
-				}
-			}
-
-			cli.ConfigureTemplate(engine, plugins)
-
-			view, err = engine.Render(nil)
-			if err != nil {
-				return
-			}
-
-			log.Debug("rendered", "view", view)
-			if *dump {
-				fmt.Println("Final:")
-				fmt.Println(string(view))
-				os.Exit(0)
-			}
-			return
-		}
+func TemplateProcessor(plugins func() discovery.Plugins) (*pflag.FlagSet, cli.ToJSONFunc, cli.FromJSONFunc, cli.ProcessTemplateFunc) {
+	services := cli.NewServices(plugins)
+	return services.ProcessTemplateFlags,
+		services.ToJSON,
+		services.FromJSON,
+		services.ProcessTemplate
 }

cmd/infrakit/base/template.go

@@ -3,6 +3,7 @@ package instance
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"os"
 	"sort"
 	"strings"
@@ -160,7 +161,7 @@ func Command(plugins func() discovery.Plugins) *cobra.Command {
 	tagsTemplate := describe.Flags().StringP("tags-view", "t", "*", "Template to render tags")
 	propertiesTemplate := describe.Flags().StringP("properties-view", "v", "{{.}}", "Template to render properties")
 
-	rawOutputFlags, rawOutput := base.RawOutput()
+	rawOutputFlags, rawOutput := cli.Output()
 	describe.Flags().AddFlagSet(rawOutputFlags)
 
 	describe.RunE = func(cmd *cobra.Command, args []string) error {
@@ -185,55 +186,50 @@ func Command(plugins func() discovery.Plugins) *cobra.Command {
 		}
 
 		desc, err := instancePlugin.DescribeInstances(filter, *properties)
-		if err == nil {
-
-			rendered, err := rawOutput(os.Stdout, desc)
-			if err != nil {
-				return err
-			}
-
-			if rendered {
-				return nil
-			}
+		if err != nil {
+			return err
+		}
+		return rawOutput(os.Stdout, desc,
+			func(io.Writer, interface{}) error {
 
-			if !*quiet {
-				if *properties {
-					fmt.Printf("%-30s\t%-30s\t%-30s\t%-s\n", "ID", "LOGICAL", "TAGS", "PROPERTIES")
+				if !*quiet {
+					if *properties {
+						fmt.Printf("%-30s\t%-30s\t%-30s\t%-s\n", "ID", "LOGICAL", "TAGS", "PROPERTIES")
 
-				} else {
-					fmt.Printf("%-30s\t%-30s\t%-s\n", "ID", "LOGICAL", "TAGS")
+					} else {
+						fmt.Printf("%-30s\t%-30s\t%-s\n", "ID", "LOGICAL", "TAGS")
+					}
 				}
-			}
-			for _, d := range desc {
+				for _, d := range desc {
 
-				logical := "  -   "
-				if d.LogicalID != nil {
-					logical = string(*d.LogicalID)
-				}
+					logical := "  -   "
+					if d.LogicalID != nil {
+						logical = string(*d.LogicalID)
+					}
 
-				tagViewBuff := ""
-				if *tagsTemplate == "*" {
-					// default -- this is a hack
-					printTags := []string{}
-					for k, v := range d.Tags {
-						printTags = append(printTags, fmt.Sprintf("%s=%s", k, v))
+					tagViewBuff := ""
+					if *tagsTemplate == "*" {
+						// default -- this is a hack
+						printTags := []string{}
+						for k, v := range d.Tags {
+							printTags = append(printTags, fmt.Sprintf("%s=%s", k, v))
+						}
+						sort.Strings(printTags)
+						tagViewBuff = strings.Join(printTags, ",")
+					} else {
+						tagViewBuff = renderTags(d.Tags, tagsView)
 					}
-					sort.Strings(printTags)
-					tagViewBuff = strings.Join(printTags, ",")
-				} else {
-					tagViewBuff = renderTags(d.Tags, tagsView)
-				}
 
-				if *properties {
-					fmt.Printf("%-30s\t%-30s\t%-30s\t%-s\n", d.ID, logical, tagViewBuff,
-						renderProperties(d.Properties, propertiesView))
-				} else {
-					fmt.Printf("%-30s\t%-30s\t%-s\n", d.ID, logical, tagViewBuff)
+					if *properties {
+						fmt.Printf("%-30s\t%-30s\t%-30s\t%-s\n", d.ID, logical, tagViewBuff,
+							renderProperties(d.Properties, propertiesView))
+					} else {
+						fmt.Printf("%-30s\t%-30s\t%-s\n", d.ID, logical, tagViewBuff)
+					}
 				}
-			}
-		}
 
-		return err
+				return nil
+			})
 	}
 
 	cmd.AddCommand(