Resolve a database connection argument

Centralizes connection handling for functions taking a conn argument. NULL opens a lazy connection that is closed when the calling function exits. An invalid (closed or stale) connection is a loud error, never a silent reconnect. Prior to v0.3.0, a silent reconnect defaulted as connect_creel_db(db_env = "prod") and could reroute a stale test connection inadvertently to prod.

Usage

.resolve_conn(conn = NULL, arg = "conn", call = parent.frame())

Arguments

conn

A DBI connection, or NULL to open one lazily.

arg

Name of the argument being resolved, for error messages.

call

Caller environment; also where the lazy connection's disconnect handler is registered.

Value

A valid DBI connection.