Path: | lib/sequel/extensions/server_block.rb |
Last Update: | Fri Oct 06 03:25:23 +0000 2017 |
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The server_block extension adds the Database#with_server method, which takes a shard argument and a block, and makes it so that access inside the block will use the specified shard by default.
First, you need to enable it on the database object:
DB.extension :server_block
Then you can call with_server:
DB.with_server(:shard1) do DB[:a].all # Uses shard1 DB[:a].server(:shard2).all # Uses shard2 end DB[:a].all # Uses default
You can nest calls to with_server:
DB.with_server(:shard1) do DB[:a].all # Uses shard1 DB.with_server(:shard2) do DB[:a].all # Uses shard2 end DB[:a].all # Uses shard1 end DB[:a].all # Uses default
Note that if you pass the nil, :default, or :read_only server/shard names to Dataset#server inside a with_server block, they will be ignored and the server/shard given to with_server will be used:
DB.with_server(:shard1) do DB[:a].all # Uses shard1 DB[:a].server(:shard2).all # Uses shard2 DB[:a].server(nil).all # Uses shard1 DB[:a].server(:default).all # Uses shard1 DB[:a].server(:read_only).all # Uses shard1 end
If you pass two separate shards to with_server, the second shard will be used instead of the :read_only shard, and the first shard will be used instead of the :default shard:
DB.with_server(:shard1, :shard2) do DB[:a].all # Uses shard2 DB[:a].delete # Uses shard1 DB[:a].server(:shard3).all # Uses shard3 DB[:a].server(:shard3).delete # Uses shard3 DB[:a].server(:default).all # Uses shard1 DB[:a].server(:read_only).delete # Uses shard2 end
Related modules: Sequel::ServerBlock, Sequel::UnthreadedServerBlock, Sequel::ThreadedServerBlock