OpenWhiskTalk

Use this command to install the Cloud Functions plugin for the IBM Cloud CLI.
```
$ bx plugin install cloud-functions
```
This plugin provides the Apache OpenWhisk CLI as a sub-command under the IBM Cloud CLI. Platform credentials are provided automatically by the IBM Cloud CLI.
1. Run the following command to invoke a test function from the command-line.
```
$ bx wsk action invoke whisk.system/utils/echo -p message hello --result
{
    "message": "hello"
}
```
Background

Actions are stateless code snippets that run on the OpenWhisk platform. An action can be written as a JavaScript, Swift, PHP, or Python function, a Java method, static binary or a custom executable packaged in a Docker container. For example, an action can be used to detect the faces in an image, respond to a database change, aggregate a set of API calls, or post a Tweet.

Actions can be explicitly invoked, or run in response to an event. In either case, each run of an action results in an activation record that is identified by a unique activation ID. The input to an action and the result of an action are a dictionary of key-value pairs, where the key is a string and the value a valid JSON value. Actions can also be composed of calls to other actions or a defined sequence of actions.

Creating Swift actions

Review the following steps and examples to create your first Swift action.
```
touch hello.swift
open hello.swift
```
1. Create a Swift file with the following content. For this example, the file name is 'hello.swift'.
```
struct Output: Codable {
    let greeting: String
}
func main(completion: (Output?, Error?) -> Void) {
    let result = Output(greeting: "Hello World!")
    completion(result, nil)
}
```
The Swift file might contain additional functions. However, by convention, a function called main must exist to provide the entry point for the action.
1. Create an action from the following Swift function. For this example, the action is called 'hello'.
```
bx wsk action create hello hello.swift --kind swift:4.1
ok: created action hello
```
1. List the actions that you have created:
```
$ bx wsk action list
actions
/user@host.com_dev/hello                                     
```
You can see the hello action you just created.

Invoking Actions

After you create your action, you can run it on IBM Cloud Functions with the 'invoke' command.
```
bx wsk action invoke --result helloSwift
```
now we are going to add an input parameter to our action:
```
struct input: Codable {
 let name: String?
 }
 func main(param: Input, completion: (Output?, Error?) -> Void) {
     let result = Output(greeting: "Hello \(param.name ?? "stranger")!")
```
now we update our action on bluemix:
```
bx wsk action update hello hello.swift
bx wsk action invoke --result hello --param name Andy
```
Show real example:
```
open weather.swift
```
create the action:
```
bx wsk action create weather weather.swift
bx wsk action invoke --result weather --param location "London"
```

Andrew-Lees11/OpenWhiskTalk

OpenWhiskTalk

Background

Creating Swift actions