Plugin showcase

Here is a showcase file which constitutes a FlexMeasures plugin called our_client.

  • We demonstrate adding a view, which can be rendered using the FlexMeasures base templates.

  • We also showcase a CLI function which has access to the FlexMeasures app object. It can be called via flexmeasures our-client test.

We first create the file <some_folder>/our_client/ This means that our_client is the plugin folder and becomes the plugin name.

With the below, plus the custom Jinja2 template, our_client is a complete plugin.

__version__ = "2.0"

from flask import Blueprint, render_template, abort

from flask_security import login_required
from flexmeasures.ui.utils.view_utils import render_flexmeasures_template

our_client_bp = Blueprint('our-client', __name__,

# Showcase: Adding a view

def my_page():
    msg = "I am a FlexMeasures plugin !"
    # Note that we render via the in-built FlexMeasures way
    return render_flexmeasures_template(

# Showcase: Adding a CLI command

import click
from flask import current_app
from flask.cli import with_appcontext = "Our client commands"

def our_client_test():
    print(f"I am a CLI command, part of FlexMeasures: {current_app}")


You can overwrite FlexMeasures routing in your plugin. In our example above, we are using the root route /. FlexMeasures registers plugin routes before its own, so in this case visiting the root URL of your app will display this plugged-in view (the same you’d see at /my-page).


The __version__ attribute on our module is being displayed in the standard FlexMeasures UI footer, where we show loaded plugins. Of course, it can also be useful for your own maintenance.

The template would live at <some_folder>/our_client/templates/my_page.html, which works just as other FlexMeasures templates (they are Jinja2 templates):

{% extends "base.html" %}

{% set active_page = "my-page" %}

{% block title %} Our client dashboard {% endblock %}

{% block divs %}

    <!-- This is where your custom content goes... -->

    {{ message }}

{% endblock %}


Plugin views can also be added to the FlexMeasures UI menu ― just name them in the config setting FLEXMEASURES_MENU_LISTED_VIEWS. In this example, add my-page. This also will make the active_page setting in the above template useful (highlights the current page in the menu).

Starting the template with {% extends "base.html" %} integrates your page content into the FlexMeasures UI structure. You can also extend a different base template. For instance, we find it handy to extend base.html with a custom base template, to extend the footer, as shown below:

{% extends "base.html" %}

{% block copyright_notice %}

Created by <a href="">Seita Energy Flexibility</a>,
in cooperation with <a href="">Our Client</a>
<script>var CurrentYear = new Date().getFullYear(); document.write(CurrentYear)</script>.

{% endblock copyright_notice %}

We’d name this file our_client_base.html. Then, we’d extend our page template from our_client_base.html, instead of base.html.

Using other code files in your non-package plugin

Say you want to include other Python files in your plugin, importing them in your file. With this file-only version of loading the plugin (if your plugin isn’t imported as a package), this is a bit tricky.

But it can be achieved if you put the plugin path on the import path. Do it like this in your

import os
import sys

HERE = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(0, HERE)

from my_other_file import my_function

Notes on writing tests for your plugin

Good software practice is to write automatable tests. We encourage you to also do this in your plugin. We do, and our CookieCutter template for plugins (see above) has simple examples how that can work for the different use cases (i.e. UI, API, CLI).

However, there are two caveats to look into:

  • Your tests need a FlexMeasures app context. FlexMeasure’s app creation function provides a way to inject a list of plugins directly. The following could be used for instance in your app fixture within the top-level if you are using pytest:

from import create as create_flexmeasures_app
from .. import __name__

test_app = create_flexmeasures_app(env="testing", plugins=[f"../"{__name__}])
  • Test frameworks collect tests from your code and therefore might import your modules. This can interfere with the registration of routes on your Blueprint objects during plugin registration. Therefore, we recommend reloading your route modules, after the Blueprint is defined and before you import them. For example:

my_plugin_ui_bp: Blueprint = Blueprint(
# Now, before we import this dashboard module, in which the "/dashboard" route is attached to my_plugin_ui_bp,
# we make sure it's being imported now, *after* the Blueprint's creation.
from my_plugin.ui.views import dashboard

The packaging path depends on your plugin’s package setup, of course.