windmill/system_prompts/base/triggers.md

Windmill Triggers

Triggers allow external events to invoke your scripts and flows.

File Naming

Trigger configuration files use the pattern: {path}.{trigger_type}_trigger.yaml

Examples:

• u/user/webhook.http_trigger.yaml
• f/data/kafka_consumer.kafka_trigger.yaml
• f/sync/postgres_cdc.postgres_trigger.yaml
• f/inbound/orders.email_trigger.yaml

Email Triggers

An email trigger routes incoming emails to a script or flow. Each trigger reserves a local-part: emails sent to <local_part>@<windmill_email_domain> are delivered to the configured runnable. Set workspaced_local_part: true to namespace it per workspace (the actual recipient becomes <workspace_id>-<local_part>@…); on Windmill Cloud this is required.

Senders may append URL-style extras to the local-part with +: mytrigger+foo=bar+baz=qux@…. They flow through to the script as email_extra_args (see below).

Payload

The runnable receives:

• parsed_email — { headers, text_body, html_body, attachments[] }. Each attachment has { headers, body }.
• raw_email — the raw RFC 822 message as a string, or an S3 object ({ s3: "windmill_emails/<job_id>/raw.eml" }) if the message exceeds 1 MiB.
• email_extra_args (optional, only when sender appended +key=value extras) — a flat object of the parsed extras.

With a preprocessor, all of the above are nested under event along with event.kind = "email" and event.trigger_path (the trigger's path). Without a preprocessor, trigger_path is not exposed — add a preprocessor if you need it.

Attachments are S3 objects

Binary attachments are uploaded to the workspace S3 bucket and surface in parsed_email.attachments[i].body as:

{ "s3": "windmill_emails/<job_id>/attachments/<filename>" }

To read the bytes inside a script, use the wmill SDK:

// TypeScript
import * as wmill from "windmill-client"
const file = await wmill.loadS3File(parsed_email.attachments[0].body)

# Python
import wmill
data = wmill.load_s3_file(parsed_email["attachments"][0]["body"])

If the workspace has no S3 resource configured (Workspace Settings → Object storage), body falls back to the string "configure s3 in the workspace settings to handle attachments". The same applies to large raw_email bodies. Email attachment storage requires the server to be built with the parquet feature.

Text/HTML/inline parts are placed inline in body as strings.

CLI Commands

Deploying local changes to the workspace can be destructive to remote state — only suggest/run a deploy when the user explicitly asks to deploy/publish/push, not when they say "run", "try", or "test". Deploy via git push or wmill sync push depending on how the repo is wired (see the Deploying section in AGENTS.wmill.md). sync pull is safe to run yourself — it never mutates remote state, though it does overwrite local files to match the remote (use sync pull --dry-run to only preview).

# Push trigger configuration — only when the user explicitly asks to deploy
wmill sync push

# Pull triggers from Windmill
wmill sync pull