Get ntfy messages¤

What it does¤

Reads the messages a topic holds and hands them on as entities, so a workflow can act on what arrived through ntfy.

What flows through the ports¤

The task consumes nothing and reads from the server itself. Its output port carries one entity per message, with the paths id, time, time_iso, topic, title, message, priority, tags, click, icon, the four attachment_* paths, and json holding the message verbatim - so a field this task does not model can still be read downstream. tags is the only path that may carry several values; every other path carries one or none. A message that was sent without a priority carries 3, the default ntfy applies to it and leaves out of its answer.

Where it sits¤

It is the reading half of this package. Get ntfy attachments fetches the files of those messages, and Send ntfy message sends in the other direction.

Caveats¤

• A run either returns everything or only what is new. Returning only new ones makes the task write the position it reached into a file in the project and continue from it next time. Each task has its own entry there, so two tasks reading one topic never take each other’s messages - but the file is written whole, so two of them finishing in the same moment can lose one of the two positions, and that task reads its window again.
• The position only advances over messages a consumer asked past. Taking an entity is not proof that it was processed, so the position follows the last message the rest of the workflow came back from. A run failing halfway leaves everything after that to be read again: a message is delivered at least once, duplicates are possible, and a lost message is not. A worker killed outright writes no position at all.
• A message published a moment ago may not be there yet. A busy server writes its message cache in batches - ntfy.sh is configured for one second - so a workflow that publishes to a topic and reads it back in the same run can come away with nothing. Reading what another run published is reliable; reading what this run published is not.
• A message id that the server has forgotten cannot be resumed from. ntfy keeps messages for twelve hours by default, so a task that has not run for longer starts from the whole window again - duplicates rather than loss.
• The preview shows what the starting point names, not the position a run would continue from, because a task action is not told which task it belongs to. Resetting the position has the same limitation and clears the position of every task reading this topic in this project.
• An unprotected topic is public, and anybody may write to it. A topic needs no sign-up and carries no password of its own, so on a server without access control anybody who guesses the name can read what is on it and publish to it - and this task hands a stranger’s message to the workflow as readily as its own. Give the topic a long random suffix rather than a word like alerts, and protect it with the server’s own access control where that is available.

Parameter¤

Server¤

The base URL of the ntfy server. The default is the public service; a self-hosted ntfy is named here instead, for example https://ntfy.example.org - see installing ntfy.

• ID: server
• Datatype: string
• Default Value: https://ntfy.sh

Access token¤

The access token to authenticate with. A public topic needs none, so this can be left empty. See access tokens.

• ID: access_token
• Datatype: password
• Default Value: None

Topic¤

The topic whose messages are read. A topic needs no sign-up and has no password of its own, so give it a long random suffix nobody can guess rather than a plain word - see picking a topic.

• ID: topic
• Datatype: string
• Default Value: None

Messages to return¤

Which of a topic’s messages a run returns.

• ID: read_mode
• Datatype: string
• Default Value: stateless

Starting point¤

How far back a run reaches: a duration such as 10m, a Unix timestamp, a message id, or all for everything the server still holds. A task set to return only new messages reads this on its first run only, and continues from its remembered position afterwards. See fetching cached messages.

• ID: since
• Datatype: string
• Default Value: all

Advanced Parameter¤

Priority filter¤

Return only messages of these priorities, as a comma separated list - each one a number from 1 to 5 or one of ntfy’s names, from min to max. A message matching any of them is returned. Empty returns every priority. See filtering messages.

• ID: priority_filter
• Datatype: string
• Default Value: None

Tag filter¤

Return only messages carrying these tags, as a comma separated list. A message must carry all of them. Empty returns every message. See filtering messages.

• ID: tags_filter
• Datatype: string
• Default Value: None

Position file¤

The project file the read positions are kept in. One file holds the positions of every task in the project and is written whole, so give a task its own file when it may finish at the same moment as another one reading the same project.

• ID: cursor_file
• Datatype: string
• Default Value: ntfy-cursors.json

Comments