tardieu commented on a change in pull request #3202: Support action
continuations in the controller
URL:
https://github.com/apache/incubator-openwhisk/pull/3202#discussion_r166299507
##########
File path: docs/compositions.md
##########
@@ -4,38 +4,44 @@ Action compositions make it possible to dynamically build
and invoke a series of
## Example
-Suppose we define an _increment_ action:
+Suppose we define an _increment_ action in a source file `increment.js`:
-```
-$ cat > increment.js
+```javascript
function main({ value }) { return { value: value + 1 } }
-^D
-
-$ wsk action create increment increment.js
```
-We can use this _increment_ action in a composition as follows:
+We create the action _increment_:
```
-$ cat > composition.js
+wsk action create increment increment.js
+```
+
+We can use this _increment_ action in a composition. We create a source file
`composition.js`:
+
+```javascript
function main(params) {
switch (params.$step || 0) {
case 0: delete params.$step; return { params, action: 'increment',
state: { $step: 1 } }
case 1: delete params.$step; return { params, action: 'increment',
state: { $step: 2 } }
case 2: delete params.$step; return { params }
}
}
-^D
+```
+
+We create the composition action:
-$ wsk action create composition composition.js -a conductor true
+```
+wsk action create composition composition.js -a conductor true
```
The key to making this action a composition is the _conductor_ annotation,
which we discuss in the next section.
This example composition executes two _increment_ actions in a sequence:
```
-$ wsk action invoke composition -br -p value 3
+wsk action invoke composition -br -p value 3
Review comment:
done
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