The precursor of the quark-gluon plasma produced in high energy heavy-ion collisions is, according to the Color Glass Condensate effective theory, a classical color field called Glasma. The Glasma is completely determined by the classical Yang-Mills equations, in which the color charges of the colliding nuclei appear as sources. We solve the Yang-Mills equations analytically in the weak-field limit, which reduces the field strength tensor components to three-dimensional integrals, that can then be evaluated numerically for different nuclear models. Specifically, we allow the nuclei to have finite extent in the longitudinal direction, which gives access to the non-trivial rapidity dependence of the energy-momentum tensor of the Glasma.