Set bone constraints via python API

Question

Is there any way to add bone constraint through python api? For example, I have two armatures:

armature1 = scene.objects['armature1']
armature2 = scene.objects['armature2']

Next, I select bone from each of armatures:

selected_bone = armature1.pose.bones["neck"]
target_bone = armature2.pose.bones["neck"]

And now I need to add a bone constraint for selected_bone to copy rotation of target_bone. Does python API have such method?

Answer 1

Here is a quick example adding a copy rotation constraint to the active pose bone (in your case selected_bone), and giving it as a target the pose bone "Bone" from armature object "Armature.001" (target_bone). Notice you use the bone's name for a subtarget.

import bpy
#context & scene for testing
context = bpy.context
scene = context.scene

#active pose bone as example
bone = context.active_pose_bone
bone2 = None
# other armature other bone
arm2 = scene.objects.get("Armature.001")
if arm2 is not None:
    bone2 = arm2.pose.bones.get("Bone")
# give it a copy rotation constraint
if bone is not None:
    crc = bone.constraints.new('COPY_ROTATION')
    #give it a target bone
    crc.target = arm2
    # note subtarget uses name not object.
    crc.subtarget = bone2.name