Castling in the French Defense? How do you decide which way to castle?

It seems castling kingside can be dangerous because of white's extra kingside space he often gets in the French Defense. Also most of my pieces are naturally on the queenside making it difficult if they're needed for defense on the kingside.  I'm curious about if castling queenside is good or not, since you use your pawns to expand on the queenside its feels like a lack of a pawn cover for your king?

Sometimes I end up not castling at all in the French because of this. I understand that the answer is rather situational but can someone explain the theory on this?
If you can block the pawn structure on the queenside then you can consider castling queenside, for example in this line

  [StartPly "12"]
  [White "White"]
  [Black "Black"]
  [FEN ""]

  1. e4 e6 2. d4 d5 3. e5 c5 4. c3 Nc6 5. Nf3 Qb6 6. a3 c4


Also in the Winawer poisoned pawn black often castles queenside in the middlegame because kingside castling is not possible and to bring the a8 rook into play eg.

  [StartPly "32"]
  [White "White"]
  [Black "Black"]
  [FEN ""]

  1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3 6. bxc3 Ne7 7. Qg4        Qc7 8. Qxg7 Rg8 9. Qxh7 cxd4 10. Ne2 Nbc6 11. f4 Bd7 12. Qd3 dxc3 13. Nxc3 a6 14. Rb1 Na5 15. h4 Nf5 16. Rh3 O-O-O  


Otherwise you generally castle kingside. Sometimes Kf8 is played to defend a pawn on g7 eg after Qg4 but that depends on the specifics.