Name: ibm-cloud-functions-cloudant-trigger
Owner: International Business Machines
Description: IBM Cloud Functions building block - Cloudant Trigger - This project provides a starting point for handling events from Cloudant with IBM Cloud Functions powered by Apache OpenWhisk.
Created: 2017-03-06 21:36:05.0
Updated: 2018-02-13 23:59:11.0
Pushed: 2018-01-28 15:23:40.0
Size: 84
Language: JavaScript
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Create Cloudant data processing apps with IBM Cloud Functions powered by Apache OpenWhisk. This tutorial should take about 5 minutes to complete. After this, move on to more complex serverless applications such as those tagged openwhisk-hands-on-demo.
If you're not familiar with the Cloud Functions/OpenWhisk programming model try the action, trigger, and rule sample first. You'll need an IBM Cloud account and the latest OpenWhisk (wsk) or IBM Cloud command line plugin (bx wsk).
This example shows how to create an action that can be integrated with the built in Cloudant changes trigger and read action to execute logic when new data is added.
Log into Bluemix, create a Cloudant database instance, and name it openwhisk-cloudant. Launch the Cloudant web console and create a database named cats. Set the corresponding names as environment variables in a terminal window:
rt CLOUDANT_INSTANCE="openwhisk-cloudant"
rt CLOUDANT_DATABASE="cats"
We will make use of the built-in OpenWhisk Cloudant package, which contains a set of actions and feeds that integrate with the Cloudant Database-as-a-Service.
With Cloud Functions on the IBM Cloud, this package can be automatically configured with the credentials and connection information from the Cloudant instance we provisioned above. We make it available by refreshing our list of packages.
sures the Cloudant credentials are available to Cloud Functions.
package refresh
Triggers can be explicitly fired by a user or fired on behalf of a user by an external event source, such as a feed. Use the code below to create a trigger to fire events when data is inserted into the cats database using the changes feed provided in the Cloudant package.
trigger create data-inserted-trigger \
feed Bluemix_${CLOUDANT_INSTANCE}_Credentials-1/changes \
param dbname "$CLOUDANT_DATABASE"
Create a file named process-change.js. This file will define an action written as a JavaScript function. This function will print out data that is written to Cloudant. For this example, we are expecting a cat with fields name and color.
tion main(params) {
turn new Promise(function(resolve, reject) {
console.log(params.name);
console.log(params.color);
if (!params.name) {
console.error('name parameter not set.');
reject({
'error': 'name parameter not set.'
});
return;
} else {
var message = 'A ' + params.color + ' cat named ' + params.name + ' was added.';
console.log(message);
resolve({
change: message
});
return;
}
;
Deploy an IBM Cloud Function from the JavaScript file.
action create process-change process-change.js
To verify the creation of our action and unit test its logic, invoke the action explicitly using the code below and pass the parameters using the --param command line arguments.
action invoke \
blocking \
param name Tahoma \
param color Tabby \
ocess-change
We now chain together multiple actions using a sequence. Here we will connect the packaged Cloudant read action with the process-change action we just created. The parameters (name and color) output from the cloudant read action will be passed automatically to our process-change action.
action create process-change-cloudant-sequence \
sequence Bluemix_${CLOUDANT_INSTANCE}_Credentials-1/read,process-change
Rules map triggers to actions. Create a rule that maps the database change trigger to the sequence we just created. Once this rule is created, the actions (or sequence of actions) will be executed whenever the trigger is fired in response to new data inserted into the Cloudant database.
rule create log-change-rule data-inserted-trigger process-change-cloudant-sequence
Begin streaming the OpenWhisk activation log in a second terminal window.
activation poll
In the Cloudant dashboard linked from the Bluemix console, create a new document in the cats database.
ame": "Tarball",
olor": "Black"
View the Cloud Functions activation log to look for the change notification. You should see activation records for the rule, the trigger, the sequence, and the actions.
move rule
rule disable log-change-rule
rule delete log-change-rule
move trigger
trigger delete data-inserted-trigger
move actions
action delete process-change-cloudant-sequence
action delete process-change
move package
package delete Bluemix_${CLOUDANT_INSTANCE}_Credentials-1
You can use the wskdeploy deployment automation tool to automate deployment of this Cloudant Trigger. Please refer to README file.
Check for errors first in the Cloud Functions activation log. Tail the log on the command line with wsk activation poll or drill into details visually with the Cloud Functions monitoring console.
If the error is not immediately obvious, make sure you have the latest version of the wsk CLI installed. If it's older than a few weeks, download an update.
property get --cliversion