wip: add List operator with Filter task

pkg/list/v0/config/definitions.json

@@ -0,0 +1,19 @@
+[
+  {
+    "available_tasks": [
+      "TASK_FILTER"
+    ],
+    "custom": false,
+    "documentation_url": "",
+    "icon": "assets/list.svg",
+    "id": "list",
+    "public": true,
+    "spec": {},
+    "title": "List",
+    "description": "Manipulate lists, filtering or summarizing their elements",
+    "uid": "5a98a721-a0df-4871-93f5-db31fd5628a6",
+    "version": "0.0.1",
+    "source_url": "https://github.com/instill-ai/operator/blob/main/pkg/list/v0",
+    "release_stage": "RELEASE_STAGE_COMING_SOON"
+  }
+]

pkg/list/v0/config/tasks.json

@@ -0,0 +1,73 @@
+{
+  "TASK_FILTER": {
+    "instillShortDescription": "Select the elements of the list that satisfy a given condition",
+    "title": "Filter",
+    "input": {
+      "instillUIOrder": 0,
+      "properties": {
+        "filter": {
+          "title": "Filter",
+          "description": "A condition to be applied to each element in the list",
+          "type": "string",
+          "instillAcceptFormats": [
+            "string"
+          ],
+          "instillUIMultiline": false,
+          "instillUIOrder": 0,
+          "instillUpstreamTypes": [
+            "value",
+            "reference",
+            "template"
+          ]
+        },
+        "list": {
+          "type": "array",
+          "title": "List",
+          "description": "The input list to be filtered. TODO check accept formats for arbitrary element type",
+          "instillAcceptFormats": [
+            "array:string"
+          ],
+          "instillUIOrder": 1,
+          "instillUpstreamTypes": [
+            "value",
+            "reference"
+          ],
+          "items": {
+            "instillUIMultiline": false,
+            "type": "string"
+          },
+          "minItems": 1
+        }
+      },
+      "required": [
+        "filter",
+        "list"
+      ],
+      "title": "Input",
+      "type": "object"
+    },
+    "output": {
+      "title": "Output",
+      "description": "Output",
+      "instillUIOrder": 0,
+      "properties": {
+        "filtered_list": {
+          "description": "A list containing only the elements that fulfilled the condition",
+          "instillEditOnNodeFields": [],
+          "instillUIOrder": 0,
+          "required": [],
+          "title": "Results",
+          "type": "array",
+          "instillFormat": "array:semi-structured/json",
+          "items": {
+            "instillFormat": "semi-structured/json"
+          }
+        }
+      },
+      "required": [
+        "filtered_list"
+      ],
+      "type": "object"
+    }
+  }
+}

pkg/list/v0/main.go

@@ -0,0 +1,90 @@
+package list
+
+import (
+	_ "embed"
+	"fmt"
+	"sync"
+
+	"github.com/gofrs/uuid"
+	"go.uber.org/zap"
+	"google.golang.org/protobuf/types/known/structpb"
+
+	"github.com/instill-ai/component/pkg/base"
+	"github.com/instill-ai/x/errmsg"
+)
+
+const (
+	taskFilter = "TASK_FILTER"
+)
+
+var (
+	//go:embed config/definitions.json
+	definitionsJSON []byte
+	//go:embed config/tasks.json
+	tasksJSON []byte
+
+	once sync.Once
+	op   base.IOperator
+)
+
+type operator struct {
+	base.Operator
+}
+
+type execution struct {
+	base.Execution
+	execute func(*structpb.Struct) (*structpb.Struct, error)
+}
+
+// Init returns an implementation of IOperator that processes JSON objects.
+func Init(logger *zap.Logger) base.IOperator {
+	once.Do(func() {
+		op = &operator{
+			Operator: base.Operator{
+				Component: base.Component{Logger: logger},
+			},
+		}
+		err := op.LoadOperatorDefinitions(definitionsJSON, tasksJSON, nil)
+		if err != nil {
+			logger.Fatal(err.Error())
+		}
+	})
+	return op
+}
+
+func (o *operator) CreateExecution(defUID uuid.UUID, task string, config *structpb.Struct, logger *zap.Logger) (base.IExecution, error) {
+	e := &execution{}
+
+	switch task {
+	case taskFilter:
+		e.execute = e.filter
+	default:
+		return nil, errmsg.AddMessage(
+			fmt.Errorf("not supported task: %s", task),
+			fmt.Sprintf("%s task is not supported.", task),
+		)
+	}
+
+	e.Execution = base.CreateExecutionHelper(e, o, defUID, task, config, logger)
+
+	return e, nil
+}
+
+func (e *execution) filter(_ /* in */ *structpb.Struct) (*structpb.Struct, error) {
+	return nil, errmsg.AddMessage(fmt.Errorf("unsupported task"), "The filter task is not available yet for execution.")
+}
+
+func (e *execution) Execute(inputs []*structpb.Struct) ([]*structpb.Struct, error) {
+	outputs := make([]*structpb.Struct, len(inputs))
+
+	for i, input := range inputs {
+		output, err := e.execute(input)
+		if err != nil {
+			return nil, err
+		}
+
+		outputs[i] = output
+	}
+
+	return outputs, nil
+}

pkg/main.go

@@ -12,6 +12,7 @@ import (
 	"github.com/instill-ai/operator/pkg/end/v0"
 	"github.com/instill-ai/operator/pkg/image/v0"
 	"github.com/instill-ai/operator/pkg/json/v0"
+	"github.com/instill-ai/operator/pkg/list/v0"
 	"github.com/instill-ai/operator/pkg/start/v0"
 	"github.com/instill-ai/operator/pkg/text/v0"
 )
@@ -40,6 +41,7 @@ func Init(logger *zap.Logger) base.IOperator {
 		operator.(*Operator).ImportDefinitions(json.Init(logger))
 		operator.(*Operator).ImportDefinitions(image.Init(logger))
 		operator.(*Operator).ImportDefinitions(text.Init(logger))
+		operator.(*Operator).ImportDefinitions(list.Init(logger))
 
 	})
 	return operator