GCODE Scripts 

Contents

GCODE Scripts

OctoPrint allows you to define custom GCODE scripts to be executed on specified occasions, e.g. when a print starts, when OctoPrint connects to a printer, or when a button defined as a custom control is clicked.

Unless configured otherwise, OctoPrint expects scripts to be located in the scripts/gcode folder in OctoPrint configuration directory (per default ~/.octoprint on Linux, %APPDATA%\OctoPrint on Windows and ~/Library/Application Support/OctoPrint on macOS).

These GCODE scripts are backed by the templating engine Jinja2, allowing more than just simple “send-as-is” scripts but making use of a full blown templating language in order to create your scripts. To this end, OctoPrint injects some variables into the template rendering context as described below.

You can find the docs on the Jinja templating engine as used in OctoPrint here.

Predefined Scripts 

The following GCODE scripts are sent by OctoPrint automatically:

afterPrinterConnected: Sent after OctoPrint successfully connected to a printer. Defaults to an empty script.

beforePrinterDisconnected: Sent just before OctoPrint (actively) closes the connection to the printer. Defaults to an empty script. Note that this will not be sent for unexpected connection cut offs, e.g. in case of errors on the serial line, only when the user clicks the “Disconnect” button or the printer requests a disconnect via an action command .

beforePrintStarted: Sent just before a print job is started. Defaults to an empty script.

afterPrintCancelled: Sent just after a print job was cancelled. Defaults to the bundled script listed below.

afterPrintDone: Sent just after a print job finished. Defaults to an empty script.

afterPrintPaused: Sent just after a print job was paused. Defaults to an empty script.

beforePrintResumed: Sent just before a print job is resumed. Defaults to an empty script.

beforeToolChange: Sent just before a tool change command (Tn) is issued.

afterToolChange: Sent just after a tool change command (Tn) is issued

Note

Plugins may extend these scripts through a hook.

Events 

Every GCODE script that is executed will emit two events. The event name will start with ‘GcodeScript’ followed by the capitalized name of the script. When afterPrintDone has started the event will be GcodeScriptAfterPrintDoneRunning and once it has completed the last event will be GcodeScriptAfterPrintDoneFinished. You can find more details in the Events documentation.

Snippets 

For making small GCODE snippets reusable in a template (e.g. for disabling all hotends) there’s an additional Jinja template command {% snippet '<snippet name>' %} available which allows including snippets stored under scripts/gcode/snippets in OctoPrint’s configuration directory. They fully support the whole spectrum of the Jinja2 templating language (that includes including other snippets).

Context 

All GCODE scripts have access to the following template variables through the template context:

printer_profile: The currently selected Printer Profile, including information such as the extruder count, the build volume size, the filament diameter etc. The individual properties follow the common data model for printer profiles.

last_position: Last position reported by the printer via M114 (might be unset if no M114 was sent so far!). Consists of x, y, z and e coordinates as received by the printer and tracked values for f and current tool t taken from commands sent through OctoPrint. All of these coordinates might be None if no position could be retrieved from the printer or the values could not be tracked (in case of f and t)!

last_temperature: Last actual and target temperature reported for all available tools and if available the heated bed. This is a dictionary of key-value pairs. The keys are the indices of the available tools (0, 1, …) and b for the heated bed. The values are a dictionary consisting of actual and target keys mapped to the corresponding temperature in degrees Celsius. Note that not all tools your printer has must necessarily be present here, neither must the heated bed - it depends on whether OctoPrint has values for a tool or the bed. Also note that actual and target might be None.

last_fanspeed: Last fan speed set. It contains the value taken from command (M106 and M107) sent through OctoPrint. The value might be None if no fan speed has been set.

script: An object wrapping the script’s type (gcode) and name (e.g. afterPrintCancelled) as script.type and script.name respectively.

plugins: An object containing variables provided by plugins (e.g plugins.myplugin.myvariable)

There are a few additional template variables available for the following specific scripts:

afterPrintPaused and beforePrintResumed

pause_position: Position reported by the printer via M114 immediately before the print was paused. See last_position above for the structure to expect here.

Please note: This will not be available if you disable “Log position on pause” under Settings > Serial > Advanced options!

pause_temperature: Last known temperature values when the print was paused. See last_temperature above for the structure to expect here.

pause_fanspeed: Last known fan speed value when the print was paused. See last_fanspeed above for the structure to expect here.

afterPrintCancelled

cancel_position: Position reported by the printer via M114 immediately before the print was cancelled. See last_position above for the structure to expect here.

Please note: This will not be available if you disable “Log position on cancel” under Settings > Serial > Advanced options!

cancel_temperature: Last known temperature values when the print was cancelled. See last_temperature above for the structure to expect here.

cancel_fanspeed: Last known fan speed value when the print was cancelled. See last_fanspeed above for the structure to expect here.

beforeToolChange and afterToolChange

tool.old: The number of the previous tool

tool.new: The number of the new tool

Warning

Note that current firmware implementations only report back one E value, the current extrusion value for the current extruder. Retrieving all E values by cycling through all extruders on pause and cancel is something OctoPrint currently does NOT do since it would simply take too long. That means that if you want to write a beforePrintResumed script that basically resets everything back to the point when the printer was paused and you are running with multiple extruders, you’ll have to find some other way to have your E values set correctly for all your available extruders - the data available in pause_position will not suffice. Additionally, most firmwares don’t report the currently selected tool in the M114 response, meaning that the only way OctoPrint can keep track of that is by tracking it itself. Same goes for the current feed rate F. So if you are printing from SD, this data will be wrong. This is also the reason why OctoPrint currently doesn’t bundle a more sophisticated pause and resume script that would actually move the print head out of the way and pause and back to the original position on resume - it might cause issues for the multitude of users out there with multi-extruder setups or for people printing from the printer’s SD, thanks to the lack of information the firmware provides.

The predefined GCODE scripts are also called with the following additional template variables:

event: The payload of the Connected, PrintStarted, PrintCancelled, PrintDone, PrintPaused or PrintResumed event. See the documentation of events for the contained values.

GCODE scripts attached to custom controls are called with the following additional template variables:

parameters: The parameters as defined for the custom control, if it has any inputs.

context: Additional context included in the definition of the custom control.

Bundled Scripts 

Out of the box, OctoPrint defaults to the following script setup for afterPrintCancelled:

Listing 3 Default afterPrintCancelled script

; disable motors
M84

;disable all heaters
{% snippet 'disable_hotends' %}
{% snippet 'disable_bed' %}

;disable fan
M106 S0

The disable_hotends snippet is defined as follows:

Listing 4 Default disable_hotends snippet

{% if printer_profile.extruder.sharedNozzle %}
M104 T0 S0
{% else %}
{% for tool in range(printer_profile.extruder.count) %}
M104 T{{ tool }} S0
{% endfor %}
{% endif %}

The disable_bed snippet is defined as follows:

Listing 5 Default disable_bed snippet

{% if printer_profile.heatedBed %}
M140 S0
{% endif %}

As you can see, the disable_hotends and disable_bed snippets utilize the printer_profile context variable in order to iterate through all available extruders and set their temperature to 0, and to also set the bed temperature to 0 if a heated bed is configured.

Examples 

More nifty pause and resume 

If you do not have a multi-extruder setup, aren’t printing from SD and have “Log position on pause” enabled under Settings > Serial Connection > Behaviour > Pausing, the following afterPrintPaused and beforePrintResumed scripts might be interesting for you. With something like them in place, OctoPrint will move your print head out of the way to a safe rest position (here G1 X0 Y0, you might want to adjust that) on pause and move it back to the persisted pause position on resume, making sure to also reset the extruder and feedrate.

Listing 6 afterPrintPaused script

; (optional) disable stepper inactivity timeout - uncomment if you printer disables steppers during pause and supports this command
;M18 S0

{% if pause_position.x is not none %}
; relative XYZE
G91
M83

; retract filament, move Z slightly upwards
G1 Z+5 E-5 F4500

; absolute XYZE
M82
G90

; move to a safe rest position, adjust as necessary
G1 X0 Y0
{% endif %}

Listing 7 beforePrintResumed script

{% if pause_position.x is not none %}
; relative extruder
M83

; prime nozzle
G1 E-5 F4500
G1 E5 F4500
G1 E5 F4500

; absolute E
M82

; absolute XYZ
G90

; reset E
G92 E{{ pause_position.e }}

; move back to pause position XYZ
G1 X{{ pause_position.x }} Y{{ pause_position.y }} Z{{ pause_position.z }} F4500

; reset to feed rate before pause if available
{% if pause_position.f is not none %}G1 F{{ pause_position.f }}{% endif %}
{% endif %}

Warning

As mentioned in the warning above and the description of the example itself, this will only work if you are not printing from SD and not using multiple extruders since OctoPrint will only then be able to track the necessary position data and print parameters due to firmware limitations.