pgconf is a simple Go package for reading/writing to PostgreSQL config file (postgresql.conf) that:
- Preseves existing whitespace and comments
- Supports single quoted and backslash-quoted values (eg.
search_path = '''$user'', \'public\'') - Supports values with optional equal sign (eg.
logconnections yes) - Works with ASCII and UTF-8
.conffiles
To read or update postgresql.conf files use the pgconf/conf package:
import (
"fmt"
"github.com/quasoft/pgconf/conf"
)
func main() {
c, err := conf.Open("/data/postgresql.conf")
if err != nil {
panic("Could not open conf file: " err.Error())
}
// StringK automatically dequotes values
dest, err := c.StringK("log_destination")
if err != nil || dest != "syslog" {
// If key was not set or has the wrong value
fmt.Println("log_destination value is not what we want, changing it now")
c.SetStringK("log_destination", "syslog") // SetStringK automatically quotes values if necessary
}
err = c.WriteFile("/data/postgresql.conf", 0644)
if err != nil {
panic("Could not save file: " err.Error())
}
}To read or update pg_hba.conf files use the pgconf/hba package:
package main
import (
"fmt"
"github.com/quasoft/pgconf/hba"
)
func main() {
conf, err := hba.Open("../../hba/testdata/sample.conf") // pg_hba.conf
if err != nil {
panic(fmt.Errorf("Failed opening file pg_hba.conf: %s", err))
}
// Find all rows for replication host-based authentication
rows, err := conf.LookupAll(hba.Database, "replication")
if err != nil {
panic(fmt.Errorf("Failed looking up for replication rows: %s", err))
}
fmt.Printf("Found %d replication rows with addresses as follows:\n", len(rows))
for _, row := range rows {
// Get and print value for ADDRESS column
address, err := conf.String(row, hba.Address)
if err != nil {
panic(fmt.Errorf("Could not read address value: %s", err))
}
fmt.Println(" - " address)
}
}outputs:
Found 3 replication rows with addresses as follows:
- 127.0.0.1/32
- ::1/128
- 10.0.0.3/32Usually it's safer to write changes to a temp file and once that writing is over to rename the temp file to the actual configuration file:
...
err = c.WriteFile("/data/postgresql.conf.tmp", 0644)
if err != nil {
panic("Could not save file: " err.Error())
}
err = os.Rename("/data/postgresql.conf.tmp", "/data/postgresql.conf")
if err != nil {
panic("Could not rename tmp file to conf: " err.Error())
}
...
}If you use this approach make sure to store the temp file in a secure location (eg. the data
dir) with restricted permissions and not inside the /tmp directory.