open-consul/sdk/freeport/freeport_test.go

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package freeport
import (
"fmt"
"io"
"net"
"testing"
"github.com/hashicorp/consul/sdk/testutil/retry"
)
func TestTakeReturn(t *testing.T) {
// NOTE: for global var reasons this cannot execute in parallel
// t.Parallel()
// Since this test is destructive (i.e. it leaks all ports) it means that
// any other test cases in this package will not function after it runs. To
// help out we reset the global state after we run this test.
defer reset()
// OK: do a simple take/return cycle to trigger the package initialization
func() {
ports, err := Take(1)
if err != nil {
t.Fatalf("err: %v", err)
}
defer Return(ports)
if len(ports) != 1 {
t.Fatalf("expected %d but got %d ports", 1, len(ports))
}
}()
waitForStatsReset := func() (numTotal int) {
t.Helper()
numTotal, numPending, numFree := stats()
if numTotal != numFree+numPending {
t.Fatalf("expected total (%d) and free+pending (%d) ports to match", numTotal, numFree+numPending)
}
retry.Run(t, func(r *retry.R) {
numTotal, numPending, numFree = stats()
if numPending != 0 {
r.Fatalf("pending is still non zero: %d", numPending)
}
if numTotal != numFree {
r.Fatalf("total (%d) does not equal free (%d)", numTotal, numFree)
}
})
return numTotal
}
// Reset
numTotal := waitForStatsReset()
// --------------------
// OK: take the max
func() {
ports, err := Take(numTotal)
if err != nil {
t.Fatalf("err: %v", err)
}
defer Return(ports)
if len(ports) != numTotal {
t.Fatalf("expected %d but got %d ports", numTotal, len(ports))
}
}()
// Reset
numTotal = waitForStatsReset()
expectError := func(expected string, got error) {
t.Helper()
if got == nil {
t.Fatalf("expected error but was nil")
}
if got.Error() != expected {
t.Fatalf("expected error %q but got %q", expected, got.Error())
}
}
// --------------------
// ERROR: take too many ports
func() {
ports, err := Take(numTotal + 1)
defer Return(ports)
expectError("freeport: block size too small", err)
}()
// --------------------
// ERROR: invalid ports request (negative)
func() {
_, err := Take(-1)
expectError("freeport: cannot take -1 ports", err)
}()
// --------------------
// ERROR: invalid ports request (zero)
func() {
_, err := Take(0)
expectError("freeport: cannot take 0 ports", err)
}()
// --------------------
// OK: Steal a port under the covers and let freeport detect the theft and compensate
leakedPort := peekFree()
func() {
leakyListener, err := net.ListenTCP("tcp", tcpAddr("127.0.0.1", leakedPort))
if err != nil {
t.Fatalf("err: %v", err)
}
defer leakyListener.Close()
func() {
ports, err := Take(3)
if err != nil {
t.Fatalf("err: %v", err)
}
defer Return(ports)
if len(ports) != 3 {
t.Fatalf("expected %d but got %d ports", 3, len(ports))
}
for _, port := range ports {
if port == leakedPort {
t.Fatalf("did not expect for Take to return the leaked port")
}
}
}()
newNumTotal := waitForStatsReset()
if newNumTotal != numTotal-1 {
t.Fatalf("expected total to drop to %d but got %d", numTotal-1, newNumTotal)
}
numTotal = newNumTotal // update outer variable for later tests
}()
// --------------------
// OK: sequence it so that one Take must wait on another Take to Return.
func() {
mostPorts, err := Take(numTotal - 5)
if err != nil {
t.Fatalf("err: %v", err)
}
type reply struct {
ports []int
err error
}
ch := make(chan reply, 1)
go func() {
ports, err := Take(10)
ch <- reply{ports: ports, err: err}
}()
Return(mostPorts)
r := <-ch
if r.err != nil {
t.Fatalf("err: %v", r.err)
}
defer Return(r.ports)
if len(r.ports) != 10 {
t.Fatalf("expected %d ports but got %d", 10, len(r.ports))
}
}()
// Reset
numTotal = waitForStatsReset()
// --------------------
// ERROR: Now we end on the crazy "Ocean's 11" level port theft where we
// orchestrate a situation where all ports are stolen and we don't find out
// until Take.
func() {
// 1. Grab all of the ports.
allPorts := peekAllFree()
// 2. Leak all of the ports
leaked := make([]io.Closer, 0, len(allPorts))
defer func() {
for _, c := range leaked {
c.Close()
}
}()
for i, port := range allPorts {
ln, err := net.ListenTCP("tcp", tcpAddr("127.0.0.1", port))
if err != nil {
t.Fatalf("%d err: %v", i, err)
}
leaked = append(leaked, ln)
}
// 3. Request 1 port which will detect the leaked ports and fail.
_, err := Take(1)
expectError("freeport: impossible to satisfy request; there are no actual free ports in the block anymore", err)
// 4. Wait for the block to zero out.
newNumTotal := waitForStatsReset()
if newNumTotal != 0 {
t.Fatalf("expected total to drop to %d but got %d", 0, newNumTotal)
}
}()
}
func TestIntervalOverlap(t *testing.T) {
cases := []struct {
min1, max1, min2, max2 int
overlap bool
}{
{0, 0, 0, 0, true},
{1, 1, 1, 1, true},
{1, 3, 1, 3, true}, // same
{1, 3, 4, 6, false}, // serial
{1, 4, 3, 6, true}, // inner overlap
{1, 6, 3, 4, true}, // nest
}
for _, tc := range cases {
t.Run(fmt.Sprintf("%d:%d vs %d:%d", tc.min1, tc.max1, tc.min2, tc.max2), func(t *testing.T) {
if tc.overlap != intervalOverlap(tc.min1, tc.max1, tc.min2, tc.max2) { // 1 vs 2
t.Fatalf("expected %v but got %v", tc.overlap, !tc.overlap)
}
if tc.overlap != intervalOverlap(tc.min2, tc.max2, tc.min1, tc.max1) { // 2 vs 1
t.Fatalf("expected %v but got %v", tc.overlap, !tc.overlap)
}
})
}
}