Tf2OpenAPI: Add CLI documentation (kubeflow#220)

* Add CLI documentation

* Add cobra as explicit dependency

* update README with correct command

Gopkg.toml

@@ -14,7 +14,8 @@ required = [
     "sigs.k8s.io/controller-runtime/pkg/source",
     "sigs.k8s.io/testing_frameworks/integration", # for integration testing
     "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1",
-    "github.com/tensorflow/tensorflow/tensorflow/go", # for tensorflow protos
+    "github.com/tensorflow/tensorflow/tensorflow/go", # for tensorflow protos,
+    "github.com/spf13/cobra"
     ]
 
 [prune]

tools/tf2openapi/README.md

@@ -1,6 +1,24 @@
 # Tf2OpenAPI
 This tool takes TensorFlow SavedModel files as inputs and generates OpenAPI 3.0 specifications for HTTP prediction requests. The SavedModel files must contain signature definitions (SignatureDefs) for models.
 
+## Usage
+```
+Usage:
+  tf2openapi [flags]
+
+Required Flags:
+  -m, --model_base_path string           Absolute path of SavedModel file
+
+Flags:
+  -h, --help                     help for tf2openapi
+  -m, --model_base_path string   Absolute path of SavedModel file
+  -n, --name string              Name of model (default "model")
+  -o, --output_file string       Absolute path of file to write OpenAPI spec to
+  -s, --signature_def string     Serving Signature Def Key
+  -v, --version string           Model version (default "1")
+
+```
+
 ## Overview
 ### Use Cases for OpenAPI
 This project is motivated by the following uses of an OpenAPI specification:
@@ -14,5 +32,5 @@ The outcome of this project is a TensorFlow-to-OpenAPI transformer which takes S
 ## Caveats
 * There is a dependency on protobufs defined by TensorFlow, e.g. [tensorflow/core/protobuf](https://github.com/tensorflow/tensorflow/tree/master/tensorflow/core/protobuf). Specific protos must be compiled into Go using [protoc](https://github.com/golang/protobuf/tree/master/protoc-gen-go) in the order: tensorflow/core/lib/core/\*.proto, tensorflow/core/framework/\*.proto, tensorflow/core/protobuf/saver.proto, tensorflow/core/protobuf/meta_graph.proto, tensorflow/core/protobuf/saved_model.proto. See Makefile which will automate this.  
 
-  ## TensorFlow Compatibility
+## TensorFlow Compatibility
 * This tool is compatible with TensorFlow versions 1.xx up to and including 1.13.1. To make it compatible with future TensorFlow versions, you will need to compile the TensorFlow protos and convert them to the internal models. See [DEVELOPER_GUIDE](DEVELOPER_GUIDE.md) for potential issues and solutions.

tools/tf2openapi/cmd/main.go

@@ -1,43 +1,61 @@
 package main
 
 import (
-	"flag"
 	"github.com/golang/protobuf/proto"
-	"github.com/kubeflow/kfserving/tools/tf2openapi/generator"
 	pb "github.com/kubeflow/kfserving/tools/tf2openapi/generated/protobuf"
+	"github.com/kubeflow/kfserving/tools/tf2openapi/generator"
+	"github.com/spf13/cobra"
 	"io/ioutil"
 	"log"
 	"os"
 )
 
 var (
-	model     = flag.String("model", "", "Absolute path of SavedModel file")
-	outFile   = flag.String("output-file", "", "Absolute path of file to write OpenAPI spec to")
-	sigDefKey = flag.String("signature-def", "", "Serving Signature Def Key ")
+	modelBasePath string
+	modelName     string
+	modelVersion  string
+	sigDefKey     string
+	outFile       string
 )
 
 /** Convert SavedModel to OpenAPI. Note that the SavedModel must have at least one signature defined**/
 func main() {
-	flag.Parse()
-	if *model == "" {
-		log.Fatalln("Please specify the absolute path of the SavedModel file")
+	rootCmd := &cobra.Command{
+		Use:   "tf2openapi",
+		Short: "tf2openapi is an OpenAPI generator for TensorFlow SavedModels",
+		Long: `This tool takes TensorFlow SavedModel files as inputs and generates OpenAPI 3.0 
+			specifications for HTTP prediction requests. The SavedModel files must 
+			contain signature definitions (SignatureDefs) for models.`,
+		Run: viewAPI,
+	}
+
+	rootCmd.Flags().StringVarP(&modelBasePath, "model_base_path", "m", "", "Absolute path of SavedModel file")
+	rootCmd.MarkFlagRequired("model_base_path")
+	rootCmd.Flags().StringVarP(&modelName, "name", "n", "model", "Name of model")
+	rootCmd.Flags().StringVarP(&modelVersion, "version", "v", "1", "Model version")
+	rootCmd.Flags().StringVarP(&outFile, "output_file", "o", "", "Absolute path of file to write OpenAPI spec to")
+	rootCmd.Flags().StringVarP(&sigDefKey, "signature_def", "s", "", "Serving Signature Def Key")
+	if err := rootCmd.Execute(); err != nil {
+		log.Fatalln(err.Error())
 	}
+}
 
-	modelPb, err := ioutil.ReadFile(*model)
+func viewAPI(cmd *cobra.Command, args []string) {
+	modelPb, err := ioutil.ReadFile(modelBasePath)
 	if err != nil {
-		log.Fatalf("Error reading file %s \n%s", *model, err.Error())
+		log.Fatalf("Error reading file %s \n%s", modelBasePath, err.Error())
 	}
 
 	/** Convert Go struct to inner model */
 	model := UnmarshalSavedModelPb(modelPb)
 
 	/** Schema generation example **/
-	spec, err := generator.GenerateOpenAPI(model, *sigDefKey)
+	spec, err := generator.GenerateOpenAPI(model, sigDefKey)
 	if err != nil {
 		log.Fatalln(err.Error())
 	}
-	if *outFile != "" {
-		f, err := os.Create(*outFile)
+	if outFile != "" {
+		f, err := os.Create(outFile)
 		if err != nil {
 			panic(err)
 		}