44"database/sql"
55"fmt"
66"io/ioutil"
7+ "net"
78"os"
89"time"
910
@@ -22,6 +23,13 @@ func Open() (string, func(), error) {
2223if err != nil {
2324return "" ,nil ,xerrors .Errorf ("create tempdir: %w" ,err )
2425}
26+ // Pick an explicit port on the host to connect to 5432.
27+ // This is necessary so we can configure the port to only use ipv4.
28+ port ,err := getFreePort ()
29+ if err != nil {
30+ return "" ,nil ,xerrors .Errorf ("Unable to get free port: %w" ,err )
31+ }
32+
2533resource ,err := pool .RunWithOptions (& dockertest.RunOptions {
2634Repository :"postgres" ,
2735Tag :"11" ,
@@ -33,6 +41,15 @@ func Open() (string, func(), error) {
3341"PGDATA=/tmp" ,
3442"listen_addresses = '*'" ,
3543},
44+ PortBindings :map [docker.Port ][]docker.PortBinding {
45+ "5432/tcp" : {{
46+ // Manually specifying a host IP tells Docker just to use an IPV4 address.
47+ // If we don't do this, we hit a fun bug:
48+ // https://github.com/moby/moby/issues/42442
49+ // where the ipv4 and ipv6 ports might be _different_ and collide with other running docker containers.
50+ HostIP :"0.0.0.0" ,
51+ HostPort :fmt .Sprintf ("%d" ,port )}},
52+ },
3653Mounts : []string {
3754// The postgres image has a VOLUME parameter in it's image.
3855// If we don't mount at this point, Docker will allocate a
@@ -76,3 +93,16 @@ func Open() (string, func(), error) {
7693_ = os .RemoveAll (tempDir )
7794},nil
7895}
96+
97+ // getFreePort asks the kernel for a free open port that is ready to use.
98+ func getFreePort () (port int ,err error ) {
99+ // Binding to port 0 tells the OS to grab a port for us:
100+ // https://stackoverflow.com/questions/1365265/on-localhost-how-do-i-pick-a-free-port-number
101+ listener ,err := net .Listen ("tcp" ,"localhost:0" )
102+ if err != nil {
103+ return 0 ,err
104+ }
105+
106+ defer listener .Close ()
107+ return listener .Addr ().(* net.TCPAddr ).Port ,nil
108+ }