[ML] Make task_type optional (#104483)

Makes the task_type element of the _inference API optional so that 
it is possible to GET, DELETE or POST to an inference entity without
providing the task type

docs/changelog/104483.yaml

@@ -0,0 +1,5 @@
+pr: 104483
+summary: Make `task_type` optional in `_inference` APIs
+area: Machine Learning
+type: enhancement
+issues: []

docs/reference/inference/delete-inference.asciidoc

@@ -6,16 +6,17 @@ experimental[]
 
 Deletes an {infer} model deployment.
 
-IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER, 
-OpenAI, or Hugging Face, in your cluster. This is not the same feature that you 
-can use on an ML node with custom {ml} models. If you want to train and use your 
+IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER,
+OpenAI, or Hugging Face, in your cluster. This is not the same feature that you
+can use on an ML node with custom {ml} models. If you want to train and use your
 own model, use the <<ml-df-trained-models-apis>>.
 
 
 [discrete]
 [[delete-inference-api-request]]
 ==== {api-request-title}
 
+`DELETE /_inference/<model_id>`
 `DELETE /_inference/<task_type>/<model_id>`
 
 [discrete]
@@ -34,15 +35,15 @@ own model, use the <<ml-df-trained-models-apis>>.
 The unique identifier of the {infer} model to delete.
 
 <task_type>::
-(Required, string)
+(Optional, string)
 The type of {infer} task that the model performs.
 
 
 [discrete]
 [[delete-inference-api-example]]
 ==== {api-examples-title}
 
-The following API call deletes the `my-elser-model` {infer} model that can 
+The following API call deletes the `my-elser-model` {infer} model that can
 perform `sparse_embedding` tasks.
 
 
@@ -61,4 +62,4 @@ The API returns the following response:
   "acknowledged": true
 }
 ------------------------------------------------------------
-// NOTCONSOLE
+// NOTCONSOLE

docs/reference/inference/get-inference.asciidoc

@@ -6,9 +6,9 @@ experimental[]
 
 Retrieves {infer} model information.
 
-IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER, 
-OpenAI, or Hugging Face, in your cluster. This is not the same feature that you 
-can use on an ML node with custom {ml} models. If you want to train and use your 
+IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER,
+OpenAI, or Hugging Face, in your cluster. This is not the same feature that you
+can use on an ML node with custom {ml} models. If you want to train and use your
 own model, use the <<ml-df-trained-models-apis>>.
 
 
@@ -18,6 +18,8 @@ own model, use the <<ml-df-trained-models-apis>>.
 
 `GET /_inference/_all`
 
+`GET /_inference/<model_id>`
+
 `GET /_inference/<task_type>/_all`
 
 `GET /_inference/<task_type>/<model_id>`

docs/reference/inference/post-inference.asciidoc

@@ -6,16 +6,17 @@ experimental[]
 
 Performs an inference task on an input text by using an {infer} model.
 
-IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER, 
-OpenAI, or Hugging Face, in your cluster. This is not the same feature that you 
-can use on an ML node with custom {ml} models. If you want to train and use your 
+IMPORTANT: The {infer} APIs enable you to use certain services, such as ELSER,
+OpenAI, or Hugging Face, in your cluster. This is not the same feature that you
+can use on an ML node with custom {ml} models. If you want to train and use your
 own model, use the <<ml-df-trained-models-apis>>.
 
 
 [discrete]
 [[post-inference-api-request]]
 ==== {api-request-title}
 
+`POST /_inference/<model_id>`
 `POST /_inference/<task_type>/<model_id>`
 
 
@@ -46,7 +47,7 @@ The unique identifier of the {infer} model.
 
 
 `<task_type>`::
-(Required, string)
+(Optional, string)
 The type of {infer} task that the model performs.
 
 

rest-api-spec/src/main/resources/rest-api-spec/api/inference.delete_model.json

@@ -12,16 +12,28 @@
     "url":{
       "paths":[
         {
-          "path":"/_inference/{task_type}/{model_id}",
+          "path": "/_inference/{inference_id}",
+          "methods": [
+            "DELETE"
+          ],
+          "parts": {
+            "inference_id": {
+              "type": "string",
+              "description": "The inference Id"
+            }
+          }
+        },
+        {
+          "path":"/_inference/{task_type}/{inference_id}",
           "methods":[
             "DELETE"
           ],
           "parts":{
             "task_type":{
               "type":"string",
-              "description":"The model task type"
+              "description":"The task type"
             },
-            "model_id":{
+            "inference_id":{
               "type":"string",
               "description":"The model Id"
             }

rest-api-spec/src/main/resources/rest-api-spec/api/inference.get_model.json

@@ -12,18 +12,30 @@
     "url":{
       "paths":[
         {
-          "path":"/_inference/{task_type}/{model_id}",
+          "path":"/_inference/{inference_id}",
+          "methods":[
+            "GET"
+          ],
+          "parts":{
+            "inference_id":{
+              "type":"string",
+              "description":"The inference Id"
+            }
+          }
+        },
+        {
+          "path":"/_inference/{task_type}/{inference_id}",
           "methods":[
             "GET"
           ],
           "parts":{
             "task_type":{
               "type":"string",
-              "description":"The model task type"
+              "description":"The task type"
             },
-            "model_id":{
+            "inference_id":{
               "type":"string",
-              "description":"The model Id"
+              "description":"The inference Id"
             }
           }
         }

rest-api-spec/src/main/resources/rest-api-spec/api/inference.inference.json

@@ -13,18 +13,30 @@
     "url":{
       "paths":[
         {
-          "path":"/_inference/{task_type}/{model_id}",
+          "path":"/_inference/{inference_id}",
+          "methods":[
+            "POST"
+          ],
+          "parts":{
+            "inference_id":{
+              "type":"string",
+              "description":"The inference Id"
+            }
+          }
+        },
+        {
+          "path":"/_inference/{task_type}/{inference_id}",
           "methods":[
             "POST"
           ],
           "parts":{
             "task_type":{
               "type":"string",
-              "description":"The model task type"
+              "description":"The task type"
             },
-            "model_id":{
+            "inference_id":{
               "type":"string",
-              "description":"The model Id"
+              "description":"The inference Id"
             }
           }
         }

rest-api-spec/src/main/resources/rest-api-spec/api/inference.put_model.json

@@ -13,18 +13,30 @@
     "url":{
       "paths":[
         {
-          "path":"/_inference/{task_type}/{model_id}",
+          "path":"/_inference/{inference_id}",
+          "methods":[
+            "PUT"
+          ],
+          "parts":{
+            "inference_id":{
+              "type":"string",
+              "description":"The inference Id"
+            }
+          }
+        },
+        {
+          "path":"/_inference/{task_type}/{inference_id}",
           "methods":[
             "PUT"
           ],
           "parts":{
             "task_type":{
               "type":"string",
-              "description":"The model task type"
+              "description":"The task type"
             },
-            "model_id":{
+            "inference_id":{
               "type":"string",
-              "description":"The model Id"
+              "description":"The inference Id"
             }
           }
         }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/DeleteInferenceModelAction.java

@@ -31,9 +31,9 @@ public static class Request extends AcknowledgedRequest<DeleteInferenceModelActi
         private final String inferenceEntityId;
         private final TaskType taskType;
 
-        public Request(String inferenceEntityId, String taskType) {
+        public Request(String inferenceEntityId, TaskType taskType) {
             this.inferenceEntityId = inferenceEntityId;
-            this.taskType = TaskType.fromStringOrStatusException(taskType);
+            this.taskType = taskType;
         }
 
         public Request(StreamInput in) throws IOException {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/InferenceAction.java

@@ -57,7 +57,7 @@ public static class Request extends ActionRequest {
             PARSER.declareObject(Request.Builder::setTaskSettings, (p, c) -> p.mapOrdered(), TASK_SETTINGS);
         }
 
-        public static Request parseRequest(String inferenceEntityId, String taskType, XContentParser parser) {
+        public static Request parseRequest(String inferenceEntityId, TaskType taskType, XContentParser parser) {
             Request.Builder builder = PARSER.apply(parser, null);
             builder.setInferenceEntityId(inferenceEntityId);
             builder.setTaskType(taskType);
@@ -197,13 +197,8 @@ public Builder setInferenceEntityId(String inferenceEntityId) {
                 return this;
             }
 
-            public Builder setTaskType(String taskTypeStr) {
-                try {
-                    TaskType taskType = TaskType.fromString(taskTypeStr);
-                    this.taskType = Objects.requireNonNull(taskType);
-                } catch (IllegalArgumentException e) {
-                    throw new ElasticsearchStatusException("Unknown task_type [{}]", RestStatus.BAD_REQUEST, taskTypeStr);
-                }
+            public Builder setTaskType(TaskType taskType) {
+                this.taskType = taskType;
                 return this;
             }
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/inference/action/PutInferenceModelAction.java

@@ -42,8 +42,8 @@ public static class Request extends AcknowledgedRequest<Request> {
         private final BytesReference content;
         private final XContentType contentType;
 
-        public Request(String taskType, String inferenceEntityId, BytesReference content, XContentType contentType) {
-            this.taskType = TaskType.fromStringOrStatusException(taskType);
+        public Request(TaskType taskType, String inferenceEntityId, BytesReference content, XContentType contentType) {
+            this.taskType = taskType;
             this.inferenceEntityId = inferenceEntityId;
             this.content = content;
             this.contentType = contentType;

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/inference/action/PutInferenceModelActionTests.java

@@ -19,14 +19,14 @@
 import java.util.Locale;
 
 public class PutInferenceModelActionTests extends ESTestCase {
-    public static String TASK_TYPE;
+    public static TaskType TASK_TYPE;
     public static String MODEL_ID;
     public static XContentType X_CONTENT_TYPE;
     public static BytesReference BYTES;
 
     @Before
     public void setup() throws Exception {
-        TASK_TYPE = TaskType.ANY.toString();
+        TASK_TYPE = TaskType.SPARSE_EMBEDDING;
         MODEL_ID = randomAlphaOfLengthBetween(1, 10).toLowerCase(Locale.ROOT);
         X_CONTENT_TYPE = randomFrom(XContentType.values());
         BYTES = new BytesArray(randomAlphaOfLengthBetween(1, 10));