camacq

Python project to control microscope through client-server program.

Install

• Install the camacq package. Python version 3.6+ is supported.

  # Check python version.
  python --version
  # Install package.
  pip install camacq
  # Test that program is callable and show help.
  camacq -h
  

Run

camacq

Configure

camacq uses a yaml configuration file, config.yml, for configuring almost all settings in the app. The configuration file is found in the configuration directory. The default configuration directory is located in the home directory and called .camacq.

The location of the configuration directory can be overridden when starting camacq.

camacq --config /my_custom_config_dir

When camacq is started it checks the configuration directory for the configuration file, and if none is found creates a default configuration file. See below for an example of how to configure the leica api and a simple automation, in the configuration yaml file.

leica:
  host: localhost
  port: 8895
  imaging_dir: '/imaging_dir'

automations:
  - name: start
    trigger:
      - type: event
        id: camacq_start_event
    action:
      - type: command
        id: start_imaging

API

To interact with a microscope camacq needs to connect to an API from a microscope vendor, which in turn will control the microscope. Currently camacq can connect to the Computer Aided Microscopy (CAM) interface of Leica Microsystems' microscopes that have that feature activated. The design of camacq is built to be able to easily extend to APIs of other microscope vendors in the future. We welcome pull requests for this and other improvements. The API interface should be contained within a separate Python library, that instantiates a client object which camacq can use.

leica:
  host: localhost
  port: 8895
  imaging_dir: '/imaging_dir'

Automations

To tell the microscope what to do, camacq uses automations. Automations are blocks of yaml consisting of triggers, optional conditions and actions. A trigger is the notification of an event in camacq, eg a new image is saved. An action is what camacq should do when the trigger triggers, eg go to the next well. A condition is a criteria that has to be true to allow the action to execute, when a trigger has triggered.

As events happen, camacq checks the configured automations to see if any automation trigger matches the event. If there is a match, it also checks for possible conditions and if they are true. If both trigger and conditions matches and resolves to true, the corresponding action(s) will be executed.

For each automation block, it is possible to have multiple triggers, multiple conditions and multiple actions. Eg we can configure an automation with two triggers and two actions. If any of the triggers matches an event, both actions will be executed, in sequence.

automations:
  name: image_next_well
  trigger:
    - type: event
      id: camacq_start_event
    - type: event
      id: well_event
      data:
        well_img_ok: true
  action:
    - type: sample
      id: set_sample
      data:
        plate_name: plate_1
        well_x: 1
        well_y: >
          {{ trigger.event.well_y + 1 }}
    - type: command
      id: start_imaging

Trigger

Let us look more closely at the trigger section of the above automation.

trigger:
  - type: event
    id: camacq_start_event
  - type: event
    id: well_event
    data:
      well_img_ok: true

This section now holds a sequence of two trigger items, where each has a type and an id. The second item also has a data key. The type key tells camacq what type of trigger it should configure. Currently only triggers of type event are available. See the documentation for all available event ids. The id key sets the trigger id which will be the first part of the matching criteria for the trigger. The second part is optional and is the value of the data key. This key can hold key-value pairs with event data that should match the attributes of the event for the trigger to trigger. So for the second item we want the event to have id well_event and to have an attribute called well_img_ok which should return True, for the event to trigger our trigger.

Action

Looking at the action section of our example automation, we see that it also has two items. And exactly as for the triggers, each action has a type and an id, and can optionally specify a data key. Actions can have different types, eg sample or command. You will find all of the action types in the documentation. For an action, the data key sets the keyword arguments that should be provided to the action handler function that executes the action.

action:
  - type: sample
    id: set_sample
    data:
      plate_name: plate_1
      well_x: 1
      well_y: >
        {{ trigger.event.well_y + 1 }}
  - type: command
    id: start_imaging

In our example we want to do two things, first set a well, and then start the imaging. To not have to define this automation for each well we want to image, automations allow for dynamic rendering of the value of a data key, via use of the Jinja2 template language. You can recognize this part by the curly brackets. See the template section below for further details.

Template

Using templates in automations allows us to build powerful and flexible pieces of automation configuration code to control the microscope. Besides having all the standard Jinja2 features, we also have the trigger event and the full sample state data available as variables when the template is rendered. Eg if a well event triggered the automation we can use trigger.event.container inside the template and have access to all the attributes of the well container that triggered the event. Useful sample attributes are also directly available on the trigger.event eg trigger.event.well_x.

well_y: >
  {% if trigger.event.container is defined %}
    {{ trigger.event.well_y + 1 }}
  {% else %}
    1
  {% endif %}

If we need access to some sample state that isn't part of the trigger, we can use samples directly in the template. Via this variable the whole sample state data is accessible from inside a template. See below for the sample attribute structure. Note that only condition and action values in key-value pairs support rendering a template. Templates are not supported in the keys of key-value pairs and not in trigger sections.

Condition

A condition can be used to check the current sample state and only execute the action if some criteria is met. Say eg we want to make sure that channel 3 of well 1:1 of plate 1 is green and that gain is set to 800.

condition:
  type: AND
  conditions:
    - condition: >
        {% if samples.leica.data['{"name": "channel", "plate_name": "plate_1", "well_x": 1, "well_y": 1, "channel_id": 3}'].values['channel_name'] == 'green' %}
          true
        {% endif %}
    - condition: >
        {% if samples.leica.data['{"name": "channel", "plate_name": "plate_1", "well_x": 1, "well_y": 1, "channel_id": 3}'].values['gain'] == 800 %}
          true
        {% endif %}

The trigger event data is also available in the condition template as a variable. Below example will evaluate to true if the well that triggered the event has either 1 or 2 as x coordinate.

condition:
  type: OR
  conditions:
    - condition: >
        {% if trigger.event.well_x == 1 %}
          true
        {% endif %}
    - condition: >
        {% if trigger.event.well_x == 2 %}
          true
        {% endif %}

Currently each condition must be a template that renders to the string true if the condition criteria is met.

Sample

The sample state should represent the sample with a representation that is specific to each implemented microscope api using the ImageContainer api of camacq. An image container has a name, a dictionary of images and a dictionary of values as attributes. The container also fires a specific event on container change.

There are two special cases of the image container. The first is the main sample container of each microscope api, eg the leica container. The main container has an extra attribute data which is a dictionary with all the containers of the sample. The second special case is the image in the dictionary of images of an image container. The image is also a container and has only itself in the images dictionary and a path attribute with the path of the image.

Eg for the leica sample there are plate, well, field, z_slice, channel and image containers under the main leica sample container.

All implemented sample states are available as a variable samples in templates in automations. The leica sample is available as samples.leica.

See below for the leica sample state attribute structure in camacq. The words in all capital letters are example values. Each image container has a name, which is either of plate, well, field, z_slice, channel or image. The different leica containers have different leica specific attributes that aren't all shown below.

samples:
  leica:
    name: leica
    images:
      PATH:
        name: image
        path: PATH
        plate_name: PLATE_NAME
        well_x: WELL_X
        well_y: WELL_Y
        field_x: FIELD_X
        field_y: FIELD_Y
        z_slice_id: Z_SLICE_ID
        channel_id: CHANNEL_ID
        images:
          PATH: self
        values:
          VALUE_KEY: VALUE
    values:
      VALUE_KEY: VALUE
    data:
      CONTAINER_ID:
        name: plate/well/field/z_slice/channel/image
        images:
          PATH:
            name: image
            path: PATH
            plate_name: PLATE_NAME
            well_x: WELL_X
            well_y: WELL_Y
            field_x: FIELD_X
            field_y: FIELD_Y
            z_slice_id: Z_SLICE_ID
            channel_id: CHANNEL_ID
            images:
              PATH: self
            values:
              VALUE_KEY: VALUE
        values:
          VALUE_KEY: VALUE

Plugins

To extend the functionality of camacq and to make it possible to do automated feedback microscopy, camacq supports plugins. A plugin is a module or a package in camacq that provides code for a specific task. It can eg be an image analysis script. See the documentation for all default available plugins.

To install a custom plugin, create a Python package with a setup.py module that implements the entry_points interface with key "camacq.plugins".

setup(
    ...
    entry_points={"camacq.plugins": "plugin_a = package_a.plugin_a"},
    ...
)

See the packaging docs for details.

camacq will automatically load installed modules or packages that implement this entry_point.

Add a setup_module coroutine function in the module or package. This function will be awaited with center and config as arguments.

async def setup_module(center, config):
    """Set up the plugin package."""

Each plugin must have its own configuration section at the root of the config.

example_plugin:
  ...

Development

Install the packages needed for development.

pip install -r requirements_dev.txt

Use the Makefile to run common development tasks.

make

Credits

A lot of the inspiration for the architecture of camacq comes from another open-source Python automation app: Home Assistant. This is also the source for the automations interface in camacq.