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Use Iter8 to send a message to a Slack channel

Iter8 provides a slack task that sends a message to a Slack channel using a webhook.

Example

In this example, you will run the Your First Experiment but at the end of the experiment, Iter8 will send a message on Slack.

The message will simply contain the experiment report in text form. However, you can easily construct a more sophisticated message by providing your own payload template.

This task could provide important updates on an experiment over Slack, for example a summary at the end of an experiment.

To summarize what will happen, you will create a new channel on Slack and configure a webhook, set up and run an experiment, and check if a message was sent to the channel.

The slack task requires the URL of the Slack webhook. To see a full list of the github task parameters, see here.

  1. Create a new channel in your Slack organization.
  2. Create a Slack app, enable incoming webhooks, and create a new incoming webhook. See here.
  3. Ensure that you have a Kubernetes cluster and the kubectl CLI. You can create a local Kubernetes cluster using tools like Kind or Minikube.
  4. Deploy the sample HTTP service in the Kubernetes cluster. 
    kubectl create deploy httpbin --image=kennethreitz/httpbin --port=80
kubectl expose deploy httpbin --port=80
  5. Launch the experiment with the slack task with the appropriate values. 
    iter8 k launch \
--set "tasks={http,assess,slack}" \
--set http.url=http://httpbin.default/get \
--set assess.SLOs.upper.http/latency-mean=50 \
--set assess.SLOs.upper.http/error-count=0 \
--set slack.url=<Slack webhook> \
--set slack.method=POST \
--set runner=job
  6. Verify that the message has been sent after the experiment has completed.
Some variations and extensions of the slack task

The default slack task payload sends the entirety of the experiment report.

However, you do not need to use the default payload. You can provide your own payload by overriding the default of the `payloadTemplateURL`.

For example, you can create a payload that selectively print out parts of the experiment report instead of the whole thing.

You can also use Slack's [Block Kit](https://api.slack.com/block-kit/building) in order to make your message more sophisticated. You can use markdown, create different sections, or add interactivity, such as buttons.

  1. Try a multi-loop experiment with an if parameter to control when the slack task is run.

    A multi-loop experiment will allow you to run the tasks on a recurring basis, allowing you to monitor your app over a course of time. For example:

    iter8 k launch \
--set "tasks={http,assess,slack}" \
--set http.url=http://httpbin.default/get \
--set assess.SLOs.upper.http/latency-mean=50 \
--set assess.SLOs.upper.http/error-count=0 \
--set slack.url=<Slack webhook> \
--set slack.method=POST \
--set runner=cronjob \
--set cronjobSchedule="*/1 * * * *"

    This will run http, assess, and slack tasks every minute. If you would like to run the slack task only during the 10th loop, use the if parameter.

      iter8 k launch \
  --set "tasks={http,assess,slack}" \
  --set http.url=http://httpbin.default/get \
  --set assess.SLOs.upper.http/latency-mean=50 \
  --set assess.SLOs.upper.http/error-count=0 \
  --set slack.url=<Slack webhook> \
  --set slack.method=POST \
  --set slack.if="Result.NumLoops == 10"
  --set runner=cronjob \
  --set cronjobSchedule="*/1 * * * *"