How Europe might react to a communist Spain in 1909

What if Spain experienced a communist revolt in 1909 on the scale of the later Spanish Civil War?

German involvement is expected, with a multinational intervention like the Boxer campaign also suggested.

A communist revolt on the scale of the later Spanish Civil War is expected to attract German involvement. A wider intervention resembling the response to the Boxer Rebellion is another possibility. The comparison imagines an assembled army from several powers under a common commander. It reflects those powers' presumed hostility to the revolution and does not establish which states would join or how the campaign would unfold.