Test of Actions in QGIS 3

InverseDirection.py

from qgis.utils import iface
#iface.activeLayer().id()
# https://gis.stackexchange.com/questions/91011/how-to-select-and-zoom-in-features-from-a-qgis-python-plugin
layer = iface.mapCanvas().layers()[0]
#layer = QgsProject.instance().mapLayer('waterways20171005162048981')
filter='"osm_id"=' + str([%osm_id%])

r = QgsFeatureRequest().setFilterExpression(filter)

features = layer.getFeatures(r)

features = [feature for feature in features]
print(features)

ids = [i.id() for i in features]

feature = features[0]

print(feature.geometry().asWkt())

geometry = feature.geometry()

lines = geometry.asMultiPolyline()

print(lines[0])

lines[0].reverse()

new_geometry = QgsGeometry.fromMultiPolylineXY(lines)

with edit(layer):
    layer.changeGeometry(feature.id(), new_geometry)
    layer.select(ids)
    iface.mapCanvas().zoomToSelected()
    iface.mapCanvas().refresh()
    print('finished')