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Rendering Jinja templates

Infrahub can natively render any Jinja templates dynamically. Internally it's referred to as Jinja2 Transform.

Please refer to Transform to learn more about it.

Generate the configuration of a device​

The rendered configuration is available via the REST API under /api/transform/jinja2/<transform_name> followed by any additional parameters expected in the GraphQL query.

The Jinja2 transform, device_startup, present in the repository expects the name of the device as a parameter /api/transform/jinja2/<transform_name>?device=<device_name>. As an example, below is the URL for couple of devices:

In these examples device_startup is the name of an transform defined in the infrahub-demo-edge repository. The query string ?device=atl1-edge2 includes all the arguments that are required by the GraphQL query associated with this transform.

Create a new branch, then change the data AND the template​

Next, we'll create a new branch and make modifications both in the data and in the template to explore the integration between the Jinja Template Renderer and the storage engine.

1. Create a new branch update-ethernet1​

From the frontend, create a new branch named update-ethernet1 and be sure to uncheck the toggle Is data only in the UI.

Create a new branch (not with Data Only)

2. Update the interface Ethernet 1 for atl1-edge1​

Now we'll make a change in the branch update-ethernet1 that will be reflected in the rendered template, like updating the documentation.

  1. Navigate to the device atl1-edge1 in the frontend
  2. Navigate to the list of its interfaces in the Interfaces Tab
  3. Select the interface Ethernet1
  4. Edit the interface Ethernet
  5. Update its description to New description in the branch
  6. Save your change

Update the description for the interface Ethernet1

3. Update the Jinja2 template in GitHub​

The final step is to modify the Jinja template directly from GitHub

In GitHub:

  1. Navigate to your clone
  2. Select the new branch in the branch menu dropdown
  3. Select the file templates / device_startup_config.tpl.j2
  4. Edit the file with the pen in the top right corner
  5. Delete the lines 77 and 78 (i.e. the last two lines of ip prefix-list BOGON-Prefixes)
  6. Commit your changes in the branch update-ethernet1 directly from GitHub

Update the template in GitHub

Validate that everything is correct

After making these changes, you should be able to render the transform for the branch update-ethernet1 and see the changes made to the data AND to the schema at the same time at the address /api/transform/jinja2/device_startup?device=atl1-edge1&branch=update-ethernet1

4. Merge the Branch update-ethernet1​

After merging the branch update-ethernet1, regenerate the configuration for atl1-edge1 in main and validate that the 2 changes are now available in main.