Path based model format detection (#251)

Author: vishalbollu

docs/apis/apis.md

@@ -8,7 +8,7 @@ Serve models at scale.
 - kind: api
   name: <string>  # API name (required)
   model: <string>  # path to an exported model (e.g. s3://my-bucket/model.zip)
-  model_format: <string>  # model format, must be "tensorflow" or "onnx"
+  model_format: <string>  # model format, must be "tensorflow" or "onnx" (default: "onnx" if model path ends with .onnx, "tensorflow" if model path ends with .zip)
   request_handler: <string>  # path to the request handler implementation file, relative to the cortex root
   compute:
     min_replicas: <int>  # minimum number of replicas (default: 1)

docs/apis/packaging-models.md

@@ -22,7 +22,6 @@ Reference your `model` in an API:
 ```yaml
 - kind: api
   name: my-api
-  model_format: tensorflow
   model: s3://my-bucket/model.zip
 ```
 
@@ -65,5 +64,4 @@ Reference your `model` in an API:
 - kind: api
   name: my-api
   model: s3://my-bucket/model.onnx
-  model_format: onnx
 ```

docs/apis/tutorial.md

@@ -26,7 +26,6 @@ Cortex requires a `cortex.yaml` file which defines a `deployment` resource. An `
 - kind: api
   name: classifier
   model: s3://cortex-examples/iris/tensorflow.zip
-  model_format: tensorflow
 ```
 
 Cortex is able to read from any S3 bucket that you have access to.

examples/iris/cortex.yaml

@@ -4,28 +4,23 @@
 - kind: api
   name: tensorflow
   model: s3://cortex-examples/iris/tensorflow.zip
-  model_format: tensorflow
 
 - kind: api
   name: pytorch
   model: s3://cortex-examples/iris/pytorch.onnx
-  model_format: onnx
   request_handler: pytorch/handler.py
 
 - kind: api
   name: xgboost
   model: s3://cortex-examples/iris/xgboost.onnx
-  model_format: onnx
   request_handler: xgboost/handler.py
 
 - kind: api
   name: sklearn
   model: s3://cortex-examples/iris/sklearn.onnx
-  model_format: onnx
   request_handler: sklearn/handler.py
 
 - kind: api
   name: keras
   model: s3://cortex-examples/iris/keras.onnx
-  model_format: onnx
   request_handler: keras/handler.py

examples/iris/keras/irises.json

@@ -1,16 +1,16 @@
 {
-    "samples": [
-        [
-            5.9,
-            3.0,
-            5.1,
-            1.8
-        ],
-        [
-            5.6,
-            2.5,
-            3.9,
-            1.1
-        ]
+  "samples": [
+    [
+      5.9,
+      3.0,
+      5.1,
+      1.8
+    ],
+    [
+      5.6,
+      2.5,
+      3.9,
+      1.1
     ]
+  ]
 }

examples/iris/xgboost/irises.json

@@ -1,16 +1,16 @@
 {
-    "samples": [
-        [
-            5.9,
-            3.0,
-            5.1,
-            1.8
-        ],
-        [
-            5.6,
-            2.5,
-            3.9,
-            1.1
-        ]
+  "samples": [
+    [
+      5.9,
+      3.0,
+      5.1,
+      1.8
+    ],
+    [
+      5.6,
+      2.5,
+      3.9,
+      1.1
     ]
+  ]
 }

pkg/operator/api/userconfig/apis.go

@@ -119,14 +119,20 @@ func (api *API) Validate() error {
 	if yaml.StartsWithEscapedAtSymbol(api.Model) {
 		api.ModelFormat = TensorFlowModelFormat
 	} else {
-		if api.ModelFormat == UnknownModelFormat {
-			return errors.Wrap(cr.ErrorMustBeDefined(), Identify(api), ModelFormatKey)
-		}
-
 		if !aws.IsValidS3Path(api.Model) {
 			return errors.Wrap(ErrorInvalidS3PathOrResourceReference(api.Model), Identify(api), ModelKey)
 		}
 
+		if api.ModelFormat == UnknownModelFormat {
+			if strings.HasSuffix(api.Model, ".onnx") {
+				api.ModelFormat = ONNXModelFormat
+			} else if strings.HasSuffix(api.Model, ".zip") {
+				api.ModelFormat = TensorFlowModelFormat
+			} else {
+				return errors.Wrap(ErrorUnableToInferModelFormat(), Identify(api))
+			}
+		}
+
 		if ok, err := aws.IsS3PathFileExternal(api.Model); err != nil || !ok {
 			return errors.Wrap(ErrorExternalNotFound(api.Model), Identify(api), ModelKey)
 		}

pkg/operator/api/userconfig/errors.go

@@ -78,6 +78,7 @@ const (
 	ErrExtraResourcesWithExternalAPIs
 	ErrImplDoesNotExist
 	ErrInvalidS3PathOrResourceReference
+	ErrUnableToInferModelFormat
 	ErrExternalNotFound
 )
 
@@ -130,6 +131,7 @@ var errorKinds = []string{
 	"err_extra_resources_with_external_apis",
 	"err_impl_does_not_exist",
 	"err_invalid_s3_path_or_resource_reference",
+	"err_unable_to_infer_model_format",
 	"err_external_not_found",
 }
 
@@ -597,6 +599,13 @@ func ErrorExternalNotFound(path string) error {
 	}
 }
 
+func ErrorUnableToInferModelFormat() error {
+	return Error{
+		Kind:    ErrUnableToInferModelFormat,
+		message: "unable to infer " + ModelFormatKey + ": path to model should end in .zip for TensorFlow models, .onnx for ONNX models, or the " + ModelFormatKey + " key must be specified",
+	}
+}
+
 func ErrorInvalidS3PathOrResourceReference(provided string) error {
 	s3ErrMsg := aws.ErrorInvalidS3Path(provided).Error()
 	return Error{