Render template with message as variables

[Splint77]

I'm trying to use a render template to genere a text based on the template and variables I pass along to it. I'm not sure if it should be possible.
I assume the input message is / can be passed along to the Home Assistant Websocket or rest api call as variables under the hood.

I see indications in the home assistant core api that variables can be passed along to template api.
https://github.com/home-assistant/core/blob/19c26b79afb08268286c5fdc93d0d00a8c6d52e2/homeassistant/components/api/__init__.py#L441-L457

I have put together a small basic example where a json object with a property named myname is injected into the render template. The returned message is not 'Name: Donald Dock' as I had hoped.

[{"id":"737c0e77a1107c7d","type":"inject","z":"0572ae7acecd5102","name":"Inject myname","props":[{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"myname\":\"Donald Duck\"}","payloadType":"json","x":240,"y":1240,"wires":[["4b450bc6e2be2eaf"]]},{"id":"4b450bc6e2be2eaf","type":"api-render-template","z":"0572ae7acecd5102","name":"Render template with myname variable","server":"","version":0,"template":"Name: {{myname}}","resultsLocation":"payload.message","resultsLocationType":"msg","templateLocation":"","templateLocationType":"none","x":510,"y":1240,"wires":[["9ed7fe6f2c6a90b9"]]},{"id":"9ed7fe6f2c6a90b9","type":"debug","z":"0572ae7acecd5102","name":"Rendered template message","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":840,"y":1240,"wires":[]}]

My end goal is to apply code in Node-Red like the following from the Alarmo project where the trigger.event.data.sensors is used inside the Jinja2 code to generate the message:

trigger:
  - platform: event
    event_type: alarmo_failed_to_arm
condition:
  - condition: template
    value_template: '{{ trigger.event.data.reason == ''open_sensors'' }}'
action:
  - service: notify.mobile_app_my_phone
    data:
      message: >
        Could not arm because of the following problems:
        {% for entity_id in trigger.event.data.sensors %}
          - {{ state_attr(entity_id, 'friendly_name') }} is {{ states(entity_id) }}
        {% endfor %}
      title: test

Source: https://github.com/nielsfaber/alarmo/tree/main

[zachowj]

[{"id":"f93d5df49593be3c","type":"api-current-state","z":"c89d915bdff0f798","name":"","server":"","version":3,"outputs":1,"halt_if":"","halt_if_type":"str","halt_if_compare":"is","entity_id":"{{payload.event.sensors}}","state_type":"str","blockInputOverrides":false,"outputProperties":[{"property":"data","propertyType":"msg","value":"","valueType":"entity"}],"for":"0","forType":"num","forUnits":"minutes","override_topic":false,"state_location":"payload","override_payload":"msg","entity_location":"data","override_data":"msg","x":608,"y":1040,"wires":[["cbf8960180ae2d8b"]]},{"id":"1ffb43c867e0eafd","type":"server-events","z":"c89d915bdff0f798","name":"","server":"","version":3,"exposeAsEntityConfig":"","eventType":"alarmo_failed_to_arm","eventData":"{\"reason\": \"open_sensors\"}","waitForRunning":true,"outputProperties":[{"property":"payload","propertyType":"msg","value":"","valueType":"eventData"}],"x":170,"y":1040,"wires":[["003cbaa76fa7e95c"]]},{"id":"25996b75552a56f8","type":"api-call-service","z":"c89d915bdff0f798","name":"","server":"","version":5,"debugenabled":false,"domain":"notify","service":"mobile_app_my_phone","areaId":[],"deviceId":[],"entityId":[],"data":"{\t   \"title\": \"test\",\t   \"message\": \"Could not arm because of the following problems:\\n\" & payload.event.sensors\t}\t        \t        ","dataType":"jsonata","mergeContext":"","mustacheAltTags":false,"outputProperties":[],"queue":"none","x":1220,"y":1040,"wires":[[]]},{"id":"003cbaa76fa7e95c","type":"split","z":"c89d915bdff0f798","name":"","splt":"\\n","spltType":"str","arraySplt":1,"arraySpltType":"len","stream":false,"addname":"","property":"payload.event.sensors","x":372,"y":1040,"wires":[["f93d5df49593be3c"]]},{"id":"cbf8960180ae2d8b","type":"template","z":"c89d915bdff0f798","name":"","field":"payload.event.sensors","fieldType":"msg","format":"handlebars","syntax":"mustache","template":"{{data.attributes.friendly_name}} is {{data.state}}","output":"str","x":862,"y":1040,"wires":[["509f7eec64955f88"]]},{"id":"509f7eec64955f88","type":"join","z":"c89d915bdff0f798","name":"","mode":"custom","build":"string","property":"payload.event.sensors","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","useparts":true,"accumulate":false,"timeout":"","count":"","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":1008,"y":1040,"wires":[["25996b75552a56f8"]]}]

You can also do this with just the events: all and call-service using JSONata to format the string call-service node data field.

[Splint77]

Thank you. I'm learning a lot from this example. First time seeing the split and join nodes in action. As well as using JSONata. So a more Node-RED based solution. I'll go this way for now :-)
It would still be cool if it could be possible to extend the render template with the message or payload as variables. More compact in Node-RED and easier to apply Home Assistant code examples to Node-RED.

[Splint77]

I kept on investigating a bit more. I saw you provide an API node as well and tried to make a "raw" post to the template rest api action.
I had success providing a json object with a template and variables properties with the alarmo_failed_to_arm example.

[{"id":"55e7cf1c2c10af3f","type":"server-events","z":"0572ae7acecd5102","name":"","server":"3198f14d.9fd26e","version":3,"exposeAsEntityConfig":"","eventType":"alarmo_failed_to_arm","eventData":"{\"reason\": \"open_sensors\"}","waitForRunning":true,"outputProperties":[{"property":"payload","propertyType":"msg","value":"","valueType":"eventData"}],"x":160,"y":2300,"wires":[["e5befbd0dd1cd169"]]},{"id":"c7adfbf55fc498c8","type":"function","z":"0572ae7acecd5102","name":"Prepare template and variables","func":"msg.payload.for_api = {}\nmsg.payload.for_api.template = msg.payload.template\nmsg.payload.for_api.variables = msg.payload.event\n\nreturn msg;","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":750,"y":2300,"wires":[["62ddd888c4af0602"]]},{"id":"faba1ef032bf2774","type":"debug","z":"0572ae7acecd5102","name":"Show result","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":1350,"y":2300,"wires":[]},{"id":"62ddd888c4af0602","type":"ha-api","z":"0572ae7acecd5102","name":"API template with template and variables","server":"3198f14d.9fd26e","version":1,"debugenabled":true,"protocol":"http","method":"post","path":"template","data":"msg.payload.for_api","dataType":"jsonata","responseType":"json","outputProperties":[{"property":"message","propertyType":"msg","value":"","valueType":"results"}],"x":1080,"y":2300,"wires":[["faba1ef032bf2774"]]},{"id":"e5befbd0dd1cd169","type":"template","z":"0572ae7acecd5102","name":"Define template without format","field":"payload.template","fieldType":"msg","format":"handlebars","syntax":"plain","template":"Could not arm because of the following problems:\n{% for entity_id in sensors %}\n- {{ state_attr(entity_id, 'friendly_name') }} is {{ states(entity_id) }}\n{% endfor %}","output":"str","x":450,"y":2300,"wires":[["c7adfbf55fc498c8"]]},{"id":"3198f14d.9fd26e","type":"server","name":"Home Assistant","version":5,"addon":true,"rejectUnauthorizedCerts":true,"ha_boolean":"y|yes|true|on|home|open","connectionDelay":true,"cacheJson":true,"heartbeat":false,"heartbeatInterval":30,"areaSelector":"friendlyName","deviceSelector":"friendlyName","entitySelector":"friendlyName","statusSeparator":"at: ","statusYear":"hidden","statusMonth":"short","statusDay":"numeric","statusHourCycle":"h23","statusTimeFormat":"h:m","enableGlobalContextStore":true}]

I use a template node to define the Jinja2 template for Home Assistant. Primarily for readablilty reasons. It is not formatted in Node-RED.
The function sets up the template and variables properties next to each other.
These are passed to the API node as the data.
And the Jinja2 is succesfully processed by Home Assistant and returned to Node-RED :-)

So this is proof of concept that variables can be passed along to Home Assistant. I would love to see this addded to your render template :-)

[zachowj]

The ability to pass variables to the render template call would be a nice addition.

I've been in the camp of why use the render template node, which has to make an additional call to HA when most of the data is already available on the NR side. But I am also behind whatever people can make work is also fine. Many ways to accomplish the same task.