Generate HTML output and send it to Slack, make output files downloadable in the web UI

README.md

@@ -10,6 +10,8 @@
 - [argo-jupyter-scheduler](#argo-jupyter-scheduler)
   - [Installation](#installation)
   - [What is it?](#what-is-it)
+  - [Optional features](#optional-features)
+    - [Sending to Slack](#sending-to-slack)
   - [A deeper dive](#a-deeper-dive)
     - [`Job`](#job)
     - [`Job Definition`](#job-definition)
@@ -52,6 +54,29 @@ If you want to run your Jupyter Notebook on a schedule, you need to be assured t
 
 The solution is Argo-Jupyter-Scheduler: Jupyter-Scheduler front-end with an Argo-Workflows back-end.
 
+## Optional features
+
+### Sending to Slack
+
+Argo-Jupyter-Scheduler allows sending HTML output of an executed notebook to a
+Slack channel:
+
+- See the Slack API docs on how to create a bot token (starts with `xoxb`)
+- Invite your bot to a Slack channel which will be used for sending output
+- When scheduling a notebook (as described above):
+  - Select a conda environment that has `papermill` installed
+  - Add the following `Parameters`:
+    - name: `SLACK_TOKEN`, value: `xoxb-<Slack bot token>`
+    - name: `SLACK_CHANNEL`, value: `<Slack channel name>` (without leading `#`, like `scheduled-jobs`).
+
+Create job:
+
+<img src="./assets/create-job-slack.png" alt="Create job Slack" width="400"/>
+
+Slack output:
+
+<img src="./assets/slack-output.png" alt="Slack output" width="800"/>
+
 ## A deeper dive
 
 In the Jupyter-Scheduler lab extension, you can create two things, a `Job` and a `Job Definition`.