When working with a model, it may sometimes be helpful to print out the design variables, constraints, and objectives as the Driver iterates. OpenMDAO provides options on the Driver to let you do that.
This example shows how to use the Driver debug printing options. The debug_print option is a list of strings. The only valid strings are 'desvars','ln_cons','nl_cons',and 'objs'.
openmdao.drivers.tests.test_scipy_optimizer.TestScipyOptimizerFeatures.test_debug_print_option