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Edge Functions (fx)

The fx extension provides access to edge functions.

Edge functions allow you to run code in response to events or requests without the complex infrastructure typically associated with building and launching microservices.

Syntax​

There are three slightly different syntaxes:

Parameterless function​

It executes function only with given name.

<OBJECT> fx(<STRING> name)

Function with parameters set via JSON or object​

<OBJECT> fx(<STRING> name, <STRING|OBJECT> json)

Example 1​

It executes the function with the name fn-name and JSON string put as the second parameter.

fx('fn-name', \"{name : 'John', age : 23}\")

Example 2​

It executes the function with the name fn-name and object as the second parameter. Extension json:getObject(...) was added as an example of an object that was used here.

fx('fn-name', json:getObject(\"{name : [{name:'John'}], age : 23}\",'$'))

Function with parameters set as pairs of arguments​

<OBJECT> fx(<STRING> name, <STRING> param1Name, <String|Bool|Int|Long|Double|Float> param1Value, ...)

Example​

It executes the function with the name fn-name, every odd parameter as a parameter 'name' or 'age', and every even parameter as a value of the parameter name John or 23.

fx('fn-name', 'name', 'John', 'age', 23)

Edge Function Stream Worker Example​

An example of stream worker that uses edge function with a name my-fn-name:

@App:name("fx-1")
@App:description("This app will execute a function every 5 seconds")
@App:qlVersion('2')

CREATE TRIGGER MyTrigger WITH ( interval = 5 sec );

CREATE SINK STREAM FxSampleStream (result object);

INSERT INTO FxSampleStream
fx('my-fn-name', 'my-param', 'my-value') as result
FROM MyTrigger;

For this example needs to be generated EdgeWorker with name my-fn-name. The easiest way is to:

  1. Generate EdgeWorker based on Query Worker with the next query:

    FOR doc IN my-colection LIMIT 1 RETURN doc

  2. Create a collection with a name my-collection.

  3. Add one document in the collection.

The following stream FxSampleStream is receiving a new message every five seconds as the result of the Edge Function.

```js
    {"result": {<my item>}}
```

If the function returns output with multiple items, then the Edge Function returns an object with multiple entries in the items property.

```js
    {"result": 
        {"items": [
            {<my item 1>},
            {<my item 2>}
        ]}
    }
```