Is she entitled to alimony or spousal support. And is it mandatory or not?

She might be, if she earns less than you. It will be mandatory if she asks for it and a court orders it, during the proceedings.

If she has been residing in California for 6 month or more and in San Diego for 3 months and more, she can file for divorce in California. There might be an argument over personal jurisdiction of California court over you to force you to pay spousal support.

There are jurisdiction requirements which your wife must meet to file in California (3 months in the County where she filed and 6 months in the State of California). She may be entitled to spousal support. Temporary spousal support is based on the income of both of you.

Entltled is not the right question. CA law allows a spouse to request spousal support if indeed there were the lesser earning spouse and the support is needed to maintain the marital standard of living. As to mandatory, the parties can agree to no spousal support. Or if the court perceives that spousal support is not warranted under FC 4320 then the court can set it at zero. Get legal assistance on this from a family law attorney.

Alimony is called Spousal Support under the California Family Code. If your wife has filled for a divorce in San Diego and meets minimum residency requirements she may request that she receive spousal support from you in San Diego. The question will then become does California have personal jurisdiction over you?