Tutorial – Add Inputs to Kestra Workflows

Inputs make your flows more dynamic and reusable.

Instead of hardcoding values in your flow, use inputs to make your workflows more adaptable to change.

Make Flows dynamic with Inputs

Defining inputs

Similar to tasks, inputs is defined as a list of key-value pairs. Each input must have an id and a type. You can also set defaults for each input. Setting default values is recommended, especially when running on a schedule. An input might be a user you’d like to send an autogenerated message to, for example taking the following flow:

id: inputs_demo
namespace: company.team

inputs:
  - id: user
    type: STRING
    defaults: Zoyd Wheeler

tasks:
  - id: hello
    type: io.kestra.plugin.core.log.Log
    message: Hey there, {{ inputs.user }}

In the Log task, you’ll notice inputs.user. To retrieve an input value, you need to identify the input in an expression. In Kestra, bracket notation {{ }} is used to wrap an expression. For an input, follow this general {{ inputs.input_id }} syntax.

In the example above, the input id is set to user, and it’s referenced in the task message as {{ inputs.user }}. Leverage autocompletion in the flow editor to use expressions; they can be tricky at first, let Kestra do the hard work.

Try running the above flow with different values for the user input. You can do this by clicking on the Execute button and then typing a new string value in the prompt for whatever name you’d like.

Input types

Here are the most common input types:

This is a very basic list to get started. Check the Inputs documentation for an extensive list of supported input types and properties.

Parameterize your flow

Now with basic Inputs in our grasp, we can parameterize the flow created earlier in Fundamentals. In our example below, we provide the URL of the API as an input rather than hardcoded into the Request task’s uri property. This allows you to change the URL at execution time without modifying the flow itself.

id: getting_started
namespace: company.team

inputs:
  - id: api_url
    type: STRING
    defaults: https://dummyjson.com/products

tasks:
  - id: api
    type: io.kestra.plugin.core.http.Request
    uri: "{{ inputs.api_url }}"

To learn more about input types, properties, and more advanced uses, check out the full Inputs documentation. Next, we check out flow results and how they can be used.