Payment Service
The payment service is a service that uses a few communiy-driven activities to build out a Flogo microservice to generate a date when payment is expected. The lab also covers Input/Output mappings and Complex object mapping.
What you’ll need
The Flogo Web UI
This demo makes use of the Flogo Web UI. If you don’t have that one running yet, please check out Getting Started with the Flogo Web UI
Kubernetes demo
This demo builds one of the services of the Kubernetes tutorial. After building this app, you might want to try and deploy it to Kubernetes too!
Need help
If you have any questions, feel free to post an issue on GitHub and tag it as a question or chat with the team and community:
- The project-flogo/Lobby Start here for all things Flogo!
- The project-flogo/developers Developer/contributor focused conversations.
Step 1: Create the app
Open the Flogo Web UI and from there, click “New” to create a new microservice and give your new app a name. Click “Create a Flow” to create a new flow and give it any name that you want. Now click on the flow you just created and to open the canvas where you can design your flow.
Step 2: Add a trigger
Triggers are used to signal a flow to run. In this case you want to receive an HTTP message to generate the date. To add a trigger, click on the “+” icon on the left hand side of the screen and select the Receive HTTP Message trigger.
The invoice ID for which you need to generate a date comes from the HTTP request. To get that parameter into the flow, you’ll need to create an Input parameter which you can do by clicking on the grey “Input Output” bar on your screen. For example, you can call the parameter “invoiceid”, keep the type as “string” and click save.
The response to the HTTP request will be a message and the HTTP status code, and to be able to send data back you’ll need to have Output parameters. You can create them by clicking on the grey “Input Output” bar on your screen. From there, select Output and configure two parameters:
- Parameter name: code
- Type: integer
Now click on the + sign to add a new parameter
- Parameter name: response
- Type: any
Now it is time to configure the trigger to listen to HTTP messages. To start, click on the trigger and a new dialog will open with a bunch of options. In this dialog you’ll have to provide:
- Port: The port on which your app will listen (set this to
9233) - Method: The HTTP method that will trigger this flow (set this to
GET) - Path: The path that will route the messages to this flow (set this to
/api/expected-date/:invoiceId, the:invoiceIdmeans that you can use that as a path parameter in your mappings)
After that, click on “Map to flow inputs” to map the invoiceId from the HTTP trigger to the “invoiceid” parameter we created earlier. The parameter will already be selected because it is the only one. Since the data will come from the PATH parameters, you’ll need to type $.pathParams.invoiceId in the input box, which means the Flogo app will expect a PATH parameter called invoiceId to be present.
With the inputs taken care off, let’s look at the outputs. Click on “Map to flow outputs” to map the output parameters you created earlier to the response of the trigger. The code parameter will already be selected, so click on “123 code” in the Flow Output section to create the mapping. Now click on “response” in the Trigger Response section and select “_* data_” from the Flow Output section to create the mapping. Click “_save_” to make sure everything is, well…, saved. You can click the little X on the top-right (no, not your browser…) to close the dialog window and go back to the flow.
Step 3: Add activities
You’ll have to add some activities to the flow for it to do something. To add an activity click on the large + sign
A list with all the activities the Flogo Web UI knows about will appear. The activity that is needed, to generate a random number, isn’t part of the out-of-the-box activities so you’ll need to import it. Click “Install new activity” and a dialog appears where you can paste (or type) the URL of where the Flogo Web UI can get the sources. For this activity you can use https://github.com/retgits/flogo-components/activity/randomnumber. From the updated list you can pick the “Random number” activity (or use the searchbar to find it) and click it to make sure it is added to the flow. As you hover over the newly added activity, a cog will appear and as you hover over that thing, a menu will appear to configure your activity. In this window you can configure the inputs of the “Random number” activity.
- max:
10(the maximum value the random number will have) - min:
0(the minimum value the random number will have)
In the same way, add a new activity and this time install the “Add to date” activity to add a number of days to the current date. The URL you’ll need to use to install the activity is https://github.com/retgits/flogo-components/activity/addtodate.
From the updated list you can pick the “Add to date” activity (or use the searchbar to find it) and click it to make sure it is added to the flow. As you hover over the newly added activity, a cog will appear and as you hover over that thing, a menu will appear to configure your activity. In this window you can configure the inputs of the “Add to date” activity.
- date:
""(leave this blank, which means using the current date) - units:
"days"(this means you’ll add days. Other possible values are"years"and"months")
For the number you’ll need to perform a mapping. Select the activity input “number” and click on the grey carret next to the Random Number activity in the “Available Data” list. This will display a list of all the outputs from that activity and you’ll need to click on “result” to populate the input box with the value of that field. As your app is running, it will mean the output of that activity will be passed in as the input for this one.
Step 4: Return data
To complete the flow, add a Return activity. Hover over it to see the cog and select configure to bring up the modal to configure the activity. The return activity is always the last activity in a branch and sets the values that are returned to the trigger. Click on “123 code” and type 200 in the input field to set the HTTP Response code to 200.
Now click on “* message” and type (or copy) the structure below. Finally click “Save” to complete the mapping.
{"id":"{{$flow.invoiceid}}","expectedDate":"{{$activity[addtodate_3].result}}"}
The above snippet maps the values from the REST service to fields that are sent back to the trigger. The mapping is done in a JavaScript-like syntax, so $flow.invoiceid means it will get the invoiceId that was used as an input parameter to the flow (the one you configured earlier) and the $activity[addtodate_3].result will get the result from the “Add to date” activity. The double curly braces are used as by Go’s templating engine.
Your final flow should look something like the one below.
Step 5: Build
Those were all the steps needed to design the flow, now let’s build an executable from it. On the main screen of your flow click on the “<” button on the top-left hand side of the screen. That will bring you back to your microservice and from here you can select “Build”. Choose whichever operating system you’re running on to download the executable.
Step 6: Run
To see the results, start your app and run curl --request GET --url http://localhost:9233/api/expected-date/12345. That will give you a result like
{"expectedDate":"2018-10-01","id":12345}