Support different trigger parameter operations (#315) (#319)

* Support different trigger parameter operations (#315)

Implemented an additional `operation` field for trigger parameters that
dictates what is to be done with the current value at `dest`. Possible
keyword values are:

 - `overwrite` Overwrite the current value (default/prior behavior)
 - `prepend` Prepend the value at `dest` with the value at `source.path`
 - `append` Append the value at `dest` with the value at `source.path`

* Specified that `operation` is optional and generated openapi specs

controllers/sensor/validate.go

@@ -156,6 +156,16 @@ func validateTriggerParameter(parameter *v1alpha1.TriggerParameter) error {
 	if parameter.Dest == "" {
 		return fmt.Errorf("parameter destination can't be empty")
 	}
+
+	switch op := parameter.Operation; op {
+	case v1alpha1.TriggerParameterOpAppend:
+	case v1alpha1.TriggerParameterOpOverwrite:
+	case v1alpha1.TriggerParameterOpPrepend:
+	case v1alpha1.TriggerParameterOpNone:
+	default:
+		return fmt.Errorf("parameter operation %+v is invalid", op)
+	}
+
 	return nil
 }
 

docs/parameterization.md

@@ -21,5 +21,6 @@ A `parameter` contains:
    1. `src`:
        1. `event`: the name of the event dependency
        2. `path`: a key within event payload to look for
-       3. `value`: default value if sensor can't find `path` in event payload.   
+       3. `value`: default value if sensor can't find `path` in event payload
    2. `dest`: destination key within resource definition whose corresponding value needs to be replaced with value from event payload
+   3. `operation`: what to do with the existing value at `dest`, either `overwrite`, `prepend`, or `append`

examples/sensors/complete-trigger-parameterization.yaml

@@ -4,6 +4,7 @@
 #   "name": "trigger-wf-1",
 #   "namespace": "argo-events",
 #   "bucket": "mybucket",
+#   "port": "9000",
 #   "key": "hello.yaml",
 #   "image": "docker/busybox",
 #  }
@@ -48,7 +49,7 @@ spec:
             bucket:
               name: THIS_WILL_BE_REPLACED_BUCKET
               key: THIS_WILL_BE_REPLACED_KEY
-            endpoint: minio-service.argo-events:9000
+            endpoint: "minio-service.argo-events:"
             insecure: true
             accessKey:
               key: accesskey
@@ -74,6 +75,12 @@ spec:
             event: "webhook-gateway:example"
             path: key
           dest: source.s3.bucket.key
+        - src:
+            event: "webhook-gateway:example"
+            path: port
+          dest: source.s3.endpoint
+          # Append the port to the existing source.s3.endpoint value
+          operation: append
       # Apply parameter for workflow
       resourceParameters:
         - src:

pkg/apis/sensor/v1alpha1/types.go

@@ -239,6 +239,21 @@ type TriggerCondition struct {
 	All []string `json:"all,omitempty" protobuf:"bytes,2,rep,name=all"`
 }
 
+// TriggerParameterOperation represents how to set a trigger destination
+// resource key
+type TriggerParameterOperation string
+
+const (
+	// TriggerParameterOpNone is the zero value of TriggerParameterOperation
+	TriggerParameterOpNone TriggerParameterOperation = ""
+	// TriggerParameterOpAppend means append the new value to the existing
+	TriggerParameterOpAppend TriggerParameterOperation = "append"
+	// TriggerParameterOpOverwrite means overwrite the existing value with the new
+	TriggerParameterOpOverwrite TriggerParameterOperation = "overwrite"
+	// TriggerParameterOpPrepend means prepend the new value to the existing
+	TriggerParameterOpPrepend TriggerParameterOperation = "prepend"
+)
+
 // TriggerParameter indicates a passed parameter to a service template
 type TriggerParameter struct {
 	// Src contains a source reference to the value of the parameter from a event event
@@ -249,6 +264,10 @@ type TriggerParameter struct {
 	// The -1 key can be used to append a value to an existing array.
 	// See https://github.com/tidwall/sjson#path-syntax for more information about how this is used.
 	Dest string `json:"dest" protobuf:"bytes,2,name=dest"`
+
+	// Operation is what to do with the existing value at Dest, whether to
+	// 'prepend', 'overwrite', or 'append' it.
+	Operation TriggerParameterOperation `json:"operation,omitempty" protobuf:"bytes,3,opt,name=operation"`
 }
 
 // TriggerParameterSource defines the source for a parameter from a event event

sensors/trigger-params.go

@@ -33,6 +33,25 @@ func applyParams(jsonObj []byte, params []v1alpha1.TriggerParameter, events map[
 		if err != nil {
 			return nil, err
 		}
+
+		switch op := param.Operation; op {
+		case v1alpha1.TriggerParameterOpAppend, v1alpha1.TriggerParameterOpPrepend:
+			// prepend or append the current value
+			current := gjson.GetBytes(jsonObj, param.Dest)
+
+			if current.Exists() {
+				if op == v1alpha1.TriggerParameterOpAppend {
+					v = current.String() + v
+				} else {
+					v = v + current.String()
+				}
+			}
+		case v1alpha1.TriggerParameterOpOverwrite, v1alpha1.TriggerParameterOpNone:
+			// simply overwrite the current value with the new one
+		default:
+			return nil, fmt.Errorf("unsupported trigger parameter operation: %+v", op)
+		}
+
 		// now let's set the value
 		tmp, err := sjson.SetBytes(jsonObj, param.Dest, v)
 		if err != nil {

sensors/trigger-params_test.go

@@ -140,6 +140,44 @@ func Test_applyParams(t *testing.T) {
 			want:    []byte(`{"x":"magaldi"}`),
 			wantErr: false,
 		},
+		{
+			name: "simpleJSON (prepended field) -> success",
+			args: args{
+				jsonObj: []byte(`{"x":"before"}`),
+				params: []v1alpha1.TriggerParameter{
+					{
+						Src: &v1alpha1.TriggerParameterSource{
+							Event: "simpleJSON",
+							Path:  "name.last",
+						},
+						Dest:      "x",
+						Operation: v1alpha1.TriggerParameterOpPrepend,
+					},
+				},
+				events: events,
+			},
+			want:    []byte(`{"x":"magaldibefore"}`),
+			wantErr: false,
+		},
+		{
+			name: "simpleJSON (appended field) -> success",
+			args: args{
+				jsonObj: []byte(`{"x":"before"}`),
+				params: []v1alpha1.TriggerParameter{
+					{
+						Src: &v1alpha1.TriggerParameterSource{
+							Event: "simpleJSON",
+							Path:  "name.last",
+						},
+						Dest:      "x",
+						Operation: v1alpha1.TriggerParameterOpAppend,
+					},
+				},
+				events: events,
+			},
+			want:    []byte(`{"x":"beforemagaldi"}`),
+			wantErr: false,
+		},
 		{
 			name: "non JSON, no default -> pass payload bytes without converting",
 			args: args{