af200de3c4
* init * test in frontend * copy files * use in cli * better * add desc to sdks * better * fix ts parsing * add docs to ts client * add docs to python client * use script prompt in frontend * regen * use in flow * rm * use in cli, create AGENTS.md instead of cursor rules * remove apply * better * better * simplify cli * more docs * cleaning * update readme * generate cli file * better folder names * fix ts * fix multiline
107 lines
2.8 KiB
Markdown
107 lines
2.8 KiB
Markdown
# Windmill Flow Building Guide
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The OpenFlow schema (openflow.openapi.yaml) is the source of truth for flow structure. Refer to OPENFLOW_SCHEMA for the complete type definitions.
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## Reserved Module IDs
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- `failure` - Reserved for failure handler module
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- `preprocessor` - Reserved for preprocessor module
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- `Input` - Reserved for flow input reference
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## Module ID Rules
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- Must be unique across the entire flow
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- Use underscores, not spaces (e.g., `fetch_data` not `fetch data`)
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- Use descriptive names that reflect the step's purpose
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## Common Mistakes to Avoid
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- Missing `input_transforms` - Rawscript parameters won't receive values without them
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- Referencing future steps - `results.step_id` only works for steps that execute before the current one
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- Duplicate module IDs - Each module ID must be unique in the flow
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## Data Flow Between Steps
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- `flow_input.property` - Access flow input parameters
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- `results.step_id` - Access output from a previous step
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- `results.step_id.property` - Access specific property from previous step output
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- `flow_input.iter.value` - Current item when inside a for-loop
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- `flow_input.iter.index` - Current index when inside a for-loop
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## Input Transforms
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Every rawscript module needs `input_transforms` to map function parameters to values:
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Static transform (fixed value):
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{"param_name": {"type": "static", "value": "fixed_string"}}
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JavaScript transform (dynamic expression):
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{"param_name": {"type": "javascript", "expr": "results.previous_step.data"}}
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## Resource References
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- For flow inputs: Use type `"object"` with format `"resource-{type}"` (e.g., `"resource-postgresql"`)
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- For step inputs: Use static value `"$res:path/to/resource"`
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## Failure Handler
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Executes when any step fails. Has access to error details:
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- `error.message` - Error message
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- `error.step_id` - ID of failed step
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- `error.name` - Error name
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- `error.stack` - Stack trace
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## S3 Object Operations
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Windmill provides built-in support for S3-compatible storage operations.
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To accept an S3 object as flow input:
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```json
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{
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"type": "object",
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"properties": {
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"file": {
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"type": "object",
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"format": "resource-s3_object",
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"description": "File to process"
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}
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}
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}
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```
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## Using Resources in Flows
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On Windmill, credentials and configuration are stored in resources. Resource types define the format of the resource.
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### As Flow Input
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In the flow schema, set the property type to `"object"` with format `"resource-{type}"`:
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```json
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{
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"type": "object",
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"properties": {
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"database": {
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"type": "object",
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"format": "resource-postgresql",
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"description": "Database connection"
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}
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}
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}
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```
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### As Step Input (Static Reference)
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Reference a specific resource using `$res:` prefix:
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```json
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{
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"database": {
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"type": "static",
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"value": "$res:f/folder/my_database"
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}
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}
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```
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