Define a Procedure
Once you have defined a problem and identified the Operations that will be used to accomplish the desired data transformation, a Procedure can be created. It is important to know about the concepts of a Procedure. Specifically, inputs, outputs, and parameters are the key topics that need to be understood.
Common Procedure Definition
Goal
Turn a raster image into XYZ tiles so that they can be viewed in a web browser. The source data is stored in a Data Ocean account, and the tiles should also be stored in Data Ocean after they have been created.
Identify the Operations
Read Source Data
dataocean_download_path
Create XYZ Tiles
raster_tiler_xyz
Write Output Data
dataocean_upload_path
Link the Operations
At this point, all the building blocks have been identified, and now they need to be connected to create the data flow. The output of the Data Ocean Read Operation should be connected with the input of the Raster Tiler XYZ Operation and the output of that should be connected to the input of the Data Ocean Write Operation.
Practical Example
Request
curl -X POST \ --data @"procedure.json" \ --header "Content-Type: application/json" \ --header 'Authorization: Bearer {TID Access Token}' \ {{ pf_api }}/api/proceduresYou can find the value for procedure.json here
Response
{ "procedure": { "account_id": "00000000-0000-0000-0000-000000000000", "client_id": "00000000-0000-0000-0000-000000000000", "identifier": "raster_tiler_xyz", "id": "abe58ec1-84a3-464a-8a1e-afe8dd00d8c7", "version": 4, "name": "Raster Tiler XYZ", "description": "Perform the raster-to-tile Operation and write to a multifile.", "status": "EXECUTABLE", "execution_status": "READY", "tags": [ "Tiles", "Raster" ], "documentation_url": null, "retired_after": null, "shared_with": [], "public": true, "regions": [ "aws-us1" ], "default_region": "aws-us1", "operations": { "dataocean_upload": { "id": "eb18f5ce-e3e3-4c45-8a34-658b8f30256f", "identifier": "dataocean_upload_path", "version": 4, "engine_name": "DataOceanOperations", "dynamic_output": false, "encrypted_parameters": [], "parameters": { "output_path": { "source": "output_path" }, "metadata": { "source": "metadata" }, "recursive": { "source": "recursive" }, "restricted_access": { "source": "restricted_access" } }, "inputs": { "input": { "sources": [ "raster_tiler_xyz:out_data" ] } }, "outputs": { "flow_control": { "data_type": "*", "description": "Other operations can use this as an input for the purpose of defining operation execution order", "name": null } } }, "raster_tiler_xyz": { "id": "ea38e5d1-3cb2-451e-a77b-c2dec296b6f7", "identifier": "raster_tiler_xyz", "version": 1, "engine_name": "fme", "dynamic_output": false, "encrypted_parameters": [], "parameters": { "tile_crs": { "source": "tile_crs" }, "tile_order": { "source": "tile_order" }, "out_format": { "source": "tile_output_format" }, "tile_export_format": { "source": "tile_export_format" } }, "inputs": { "in_data": { "sources": [ "dataocean_download:output" ] } }, "outputs": { "out_data": { "data_type": "data:other", "description": "The tilepack that will be exported.", "name": "Output Data" } } }, "dataocean_download": { "id": "b12306ae-6cb4-49ac-940a-ea041527fa54", "identifier": "dataocean_download_path", "version": 4, "engine_name": "DataOceanOperations", "dynamic_output": false, "encrypted_parameters": [], "parameters": { "source_path": { "source": "source_path" } }, "inputs": {}, "outputs": { "output": { "data_type": "*", "description": "The file or directory downloaded from Data Ocean." } } } }, "parameters": { "tile_crs": { "name": "Tile Coordinate System", "description": "The CRS of the tilepack. Either EPSG:3857 or EPSG:4326." }, "tile_order": { "name": "Tile Order", "description": "The desired tile order schema of the tilepack. This can either be YX or XY" }, "tile_output_format": { "name": "Tile File Format", "description": "The desired output file format for the tiles. This must be a valid FME format shortname." }, "tile_export_format": { "name": "Exported Tile Format", "description": "The desired style of tiles to output. This can either be XYZ or OGC GeoPackage." }, "source_path": { "name": "Data Ocean: Source Path", "description": "The desired input path of the Data Ocean file." }, "output_path": { "name": "Data Ocean: Output Path", "description": "The desired output path of the Data Oceaan file." }, "metadata": { "name": "Data Ocean: Metadata", "description": "JSON-encoded string of metadata to add to the File object." }, "recursive": { "name": "Data Ocean: Recursive", "description": "Whether or not to upload the output recursively. When false, a singe output file is expected." }, "restricted_access": { "default_value": "false", "name": "Data Ocean: Restricted Access", "description": "Whether the Data Ocean File object is to be public or not." } } }}Additional Information
Operation Parameters v. Procedure Parameters
It is important to understand the difference between the parameters that an Operation has and subsequently the parameters that a Procedure exposes to the client. This distinction is important because an Operation may have required and/or optional parameters. This will influence the parameters exposed in the context of a Procedure.
Default Values
Procedure parameters support the ability to define default values. This is offered as a convenience to the Procedure author if they want to provide an interface to their user and allow them to omit some parameters. If the client omits the parameter, then the default value will be used.
Fixed Values
Fixed value parameters are a useful feature of the Procedure that allows the author to explicitly set the value to be used without allowing for any ability to set a different value at the Execution. This simplifies the parameter interface for the Procedure consumer and also provides control to the author to lock in a desired value so it can not be modified.
Output Parameters
Some Operations provide the ability to pass information between Operations in JSON format. These are called Output Parameters. The author of an Operation will have defined content that will be found in the output parameters section of a Procedure Execution. This data can subsequently be used by a consuming application or as an input to a downstream Operation.
Control Flow
Processing Framework provides a “Switcher” Operation which allows for conditional control flow within a Procedure. The Switcher evaluates condition expressions at execution time and determines which downstream Operations get executed. For full details, supported operators, and examples, see Control Flow.