Files
LambdaMail/services/protocols/internal/e2e/ports_test.go
T

108 lines
3.4 KiB
Go

package e2e
import (
"os"
"path/filepath"
"regexp"
"strconv"
"strings"
"testing"
)
// Every embedded Postgres in this package binds a fixed port, and those ports
// must sit below the kernel's ephemeral range.
//
// They did not. All sixteen were inside 32768-60999, which is the range Linux
// draws source ports from for outgoing connections. Nothing in this repository
// was listening on them - the kernel simply handed one out to some unrelated
// connection at the moment a test tried to bind it, and that test died with
// "process already listening on port 54340". It is a race, so it failed rarely
// and never in the same place twice, which is exactly what makes it expensive.
//
// This test reads the ports out of the source rather than from a list someone
// has to remember to update: the next person adding an e2e test gets told here
// instead of by a red build a week later.
// ephemeralFloor is the lowest port Linux will hand out as a source port
// (net.ipv4.ip_local_port_range). Staying below it means the kernel will never
// allocate one of these behind our back.
const ephemeralFloor = 32768
var portPattern = regexp.MustCompile(`Port\((\d+)\)`)
func TestEmbeddedPostgresPortsAreOutsideTheEphemeralRange(t *testing.T) {
entries, err := filepath.Glob("*_test.go")
if err != nil {
t.Fatalf("glob: %v", err)
}
found := 0
for _, name := range entries {
source, err := os.ReadFile(name)
if err != nil {
t.Fatalf("read %s: %v", name, err)
}
for _, match := range portPattern.FindAllStringSubmatch(string(source), -1) {
port, err := strconv.Atoi(match[1])
if err != nil {
continue
}
found++
if port >= ephemeralFloor {
t.Errorf("%s binds port %d, which is inside the kernel's ephemeral "+
"range (>= %d): the kernel can hand it to an unrelated connection "+
"and this test will fail intermittently with "+
"\"process already listening\". Pick a port below %d.",
name, port, ephemeralFloor, ephemeralFloor)
}
}
}
if found == 0 {
t.Fatal("no embedded Postgres ports found; this test is no longer checking anything")
}
}
// Two tests sharing a port would collide every time rather than intermittently.
func TestEmbeddedPostgresPortsAreUnique(t *testing.T) {
entries, _ := filepath.Glob("*_test.go")
seen := map[int]string{}
for _, name := range entries {
source, err := os.ReadFile(name)
if err != nil {
t.Fatalf("read %s: %v", name, err)
}
for _, match := range portPattern.FindAllStringSubmatch(string(source), -1) {
port, _ := strconv.Atoi(match[1])
if previous, taken := seen[port]; taken {
t.Errorf("port %d is bound by both %s and %s", port, previous, name)
}
seen[port] = name
}
}
}
// The port in the connection string has to be the one the server was started
// on, or the test connects to whatever else happens to be there.
func TestEachTestConnectsToThePortItStarted(t *testing.T) {
entries, _ := filepath.Glob("*_test.go")
for _, name := range entries {
source, err := os.ReadFile(name)
if err != nil {
t.Fatalf("read %s: %v", name, err)
}
text := string(source)
matches := portPattern.FindAllStringSubmatch(text, -1)
if len(matches) != 1 {
continue
}
port := matches[0][1]
if strings.Contains(text, "postgres://") && !strings.Contains(text, "localhost:"+port) {
t.Errorf("%s starts Postgres on port %s but its connection string points "+
"somewhere else", name, port)
}
}
}