DB client libs really should have this built in. Even the heavy-handed things wrapping them don't. I have my own that I copy into every new project with things

DB client libs really should have this built in. Even the heavy-handed things wrapping them don't. I have my own that I copy into every new project with things like xactReadWrite(innerFunc) and xactReadOnly(innerFunc), where the read-only randomly picks from a pool of connections to read replicas.