filter

README

Filter

This activity allows you to filter out data in a streaming pipeline, can also be used in flows.

Installation

Flogo CLI

flogo install github.com/project-flogo/stream/activity/filter

Metadata

{
  "settings": [
    {
      "name": "type",
      "type": "string",
      "required": true,
      "allowed" : ["non-zero"]
    },
    {
      "name": "proceedOnlyOnEmit",
      "type": "boolean"
    }
  ],
  "input":[
    {
      "name": "value",
      "type": "any"
    }
  ],
  "output": [
    {
      "name": "filtered",
      "type": "boolean"
    },
    {
      "name": "value",
      "type": "any"
    }
  ]
}

Details

Settings:

Setting	Required	Description
type	true	The type of filter to apply (ex. non-zero)
proceedOnlyOnEmit	false	Indicates that the next activity should proceed, true by default
note : if using this activity in a flow, proceedOnlyOnEmit should be set to false

Input:

Name	Description
value	The input value

Output:

Name	Description
filtered	Indicates if the value was filtered out
value	The input value, it is 0 if it was filtered out

Example

The example below filters out all zero 'movement' readings

{
  "id": "filter1",
  "name": "Filter",
  "activity": {
    "ref": "github.com/project-flogo/activity/filter",
    "settings": {
      "type": "non-zero"
    },
    "mappings": {
      "input": [
        {
          "type": "assign",
          "value": "movement",
          "mapTo": "value"
        }
      ]
    }
  }
}

Documentation

Index

• func IsNonZero(val interface{}) bool
• func New(ctx activity.InitContext) (activity.Activity, error)
• type Activity
  • func (a *Activity) Eval(ctx activity.Context) (done bool, err error)
  • func (a *Activity) Metadata() *activity.Metadata
• type Filter
• type Input
• type NonZeroFilter
  • func (*NonZeroFilter) FilterOut(val interface{}) bool
• type Output
• type Settings

Functions

func IsNonZero

func IsNonZero(val interface{}) bool

func New

func New(ctx activity.InitContext) (activity.Activity, error)

Types

type Activity

type Activity struct {
	// contains filtered or unexported fields
}

Activity is an Activity that is used to Filter a message to the console

func (*Activity) Eval

func (a *Activity) Eval(ctx activity.Context) (done bool, err error)

Eval implements api.Activity.Eval - Filters the Message

func (*Activity) Metadata

func (a *Activity) Metadata() *activity.Metadata

Metadata returns the activity's metadata

type Filter

type Filter interface {
	FilterOut(val interface{}) bool
}

type Input

type Input struct {
	Value interface{} `md:"value"`
}

type NonZeroFilter

type NonZeroFilter struct {
}

func (*NonZeroFilter) FilterOut

func (*NonZeroFilter) FilterOut(val interface{}) bool

type Output

type Output struct {
	Filtered bool        `md:"filtered"`
	Value    interface{} `md:"value"`
}

type Settings

type Settings struct {
	Type              string `md:"type,allowed(non-zero)"`
	ProceedOnlyOnEmit bool
}

we can generate json from this! - we could also create a "validate-able" object from this