v1.17.0 - PostgresPool and Unix Socket support

What's new

PostgresPool

A new pgmoon.pool module provides a connection pool that matches the Postgres interface, so it can be used as a drop-in replacement when you need to issue queries from multiple coroutines concurrently.

local PostgresPool = require("pgmoon.pool").PostgresPool
local pool = PostgresPool({
  host = "127.0.0.1", database = "mydb", user = "postgres",
  max_pool_size = 10
})
assert(pool:connect())
local res = assert(pool:query("select * from users limit 10"))

For multi-query transactions, pool:reserve() / pool:release(pg) give you exclusive access to a single connection. Releasing a connection that's still in a transaction will automatically issue a ROLLBACK to keep the pool clean. See the README's PostgresPool section for the full API.

Unix socket connections (socket_path)

You can now connect over a Unix domain socket by passing socket_path to Postgres.new:

local pg = pgmoon.new({
  socket_path = "/var/run/postgresql/.s.PGSQL.5432",
  database = "mydb", user = "postgres",
})

In OpenResty this uses the cosocket unix: syntax. Outside OpenResty it requires luaposix (luarocks install luaposix).

transaction_status

The Postgres object now exposes a transaction_status field that reflects the server's reported transaction state after each query: "I" (idle), "T" (in transaction), or "E" (failed transaction, awaiting ROLLBACK). This is also used by keepalive to auto-ROLLBACK dirty connections before returning them to the OpenResty pool.

Connection busy tracking

connect, query, disconnect, keepalive, and wait_for_notification now raise "pgmoon: connection is busy" if invoked while the connection is already mid-operation (e.g. from another coroutine that yielded mid-query) rather than silently corrupting the protocol stream. If you need concurrent access, use PostgresPool.

Other changes

• Add deserializer for inet[] arrays (oid 1041)
• More descriptive error message when the server requests a password but none was provided
• Doc fix for pool_name config option (#142)
• Numerous README typo and example fixes