Learn Expression syntax and tiny math, where?

Elastic Stack Kibana
1

Hi!

Is there an online course that teaches this? I struggle to understand the syntax and how to use it to change things in the Canvas.

The expression syntax, is that unique to Kibana, or is it a “real” language used outside of Kibana? I want to get an overview, like how everything is connected, the essql query and the expression syntax afterwards.

I have red the function reference but struggle to apply it to my canvases.

/Jens

2

Hi @JensHaglof . Sorry to hear about your trouble with Canvas expressions.

The expression syntax, is that unique to Kibana, or is it a “real” language used outside of Kibana?

It is unique to Kibana. But it uses pipe-able expressions which is a construct used in some other languages.

I want to get an overview, like how everything is connected, the essql query and the expression syntax afterwards.

When using the Function Reference it can be helpful to see what argument(s) the function accepts and what it returns. For example, the essql function accepts a kibana_context and returns a datatable. And the pointseries function can accept a datatable and return a pointseries. The plot function accepts a pointseries and returns a render. The render function accepts the render returned from the plot function and draws the chart on the screen.

There are a few helpful examples that demonstrate this in the function reference like this one under axisConfig.

Also, I’ve found many complex examples of expressions from the community here on Discuss. And if you run into a specific issue, you can always create a new post in Discuss and ask the community for help.

3

Hi Nick! Thanks for the answer. :slight_smile:

I just find it hard to know how to write the syntax. From the reference:
```

| staticColumn name="totalA" value={var "logs" | getCell "a"}

| alterColumn column="totalA" type="number"

```

Sometimes you use “{“ sometimes not. And sometimes you need to put a pipe in there. If I understand it correctly, when you put a pipe in the code you change which variable you affect with your code?

4

Hi Jens. I believe the syntax for using brackets is {some-expression} which is what your staticColumn example is doing. The value is being constructed via some expression where the “logs” var is being passed into the getCell function. In the alterColumn example, the column and type properties are literals, not expressions.

5

Ok, thank you, Nick! It’s still a bit confusing, but I’ll post here if I run into any issues.

I have another question:
On the Canvas page under My Workpads, is it possible to organize workpads into folders? We currently have a lot—close to 40—including ones used in production, test workpads, and bug check dashboards. And the list is increasing. Is there a way to group them, or do we just have to scroll through the full list every time?