constant process not supported

[ElienVandermaesenVITO]

[400] BadRequest: java.lang.IllegalArgumentException: Unsupported operation: constant (arguments: [x]) (ref: r-2412044031e84b1e9ada557ecc1d9115)
Process graph from Open-EO/openeo-community-examples#58 (comment)

[jdries]

The 'constant' process needs to be added to this switch statement:

openeo-geotrellis-extensions/openeo-geotrellis/src/main/scala/org/openeo/geotrellis/OpenEOProcessScriptBuilder.scala

Line 1116 in bb509dc

case "date_difference" => dateDifferenceProcess(arguments)

The actual implementation for numbers already exists, and can be found here:

openeo-geotrellis-extensions/openeo-geotrellis/src/main/scala/org/openeo/geotrellis/OpenEOProcessScriptBuilder.scala

Line 1030 in bb509dc

def constantArrayElement(value: Number):Unit = {

So the work here is to add one line of code, and a test.
For the test, we could in fact make a slight modification to an existing one, which now often uses constants but not via this process, e.g.:

openeo-geotrellis-extensions/openeo-geotrellis/src/test/java/org/openeo/geotrellis/TestOpenEOProcessScriptBuilder.java

Line 266 in d7e317d

builder.constantArgument("y", 10);