postgres

Overview ¶

Package postgres is the PostgreSQL provider for the database package: it constructs the connection pool over pgx's database/sql adapter and supplies the postgres dialect. The pgx dependency lives in this sub-module's go.mod, so it enters a consumer's graph only when this package is imported — once, at the composition root.

Construction ¶

New builds the pool from a finalized database.Config without I/O: it composes a postgres:// URL with net/url from the host, port (defaulting to 5432), name, user, and Options, parses it eagerly with pgx.ParseConfig — a malformed config is a construction error, not a first-query surprise — and then sets the password and connect timeout as fields on the parsed config. The password never enters the composed URL, so no character in it can break or leak through the connection string. An empty user falls back to pgx's default, the OS username. Options keys that name connection fields (host, port, user, password, dbname, database, connect_timeout) are rejected; values pgx cannot parse, such as an invalid sslmode, fail with the parse error.

The result is a *database.DB: lifecycle wiring, readiness, and the query surface come from the base package, and the Provider constant supports typed selection at the composition root.

Dialect ¶

The dialect names itself "postgres", renders bind placeholders as $1, $2, …, and maps errors as the identity at the connectivity slice — classification of constraint violations arrives with the write surface.