Function TestDaemonHostGatewayIP

integration/container/daemon_linux_test.go:136–173

TestDaemonHostGatewayIP verifies that when a magic string "host-gateway" is passed to ExtraHosts (--add-host) instead of an IP address, its value is set to 1. Daemon config flag value specified by host-gateway-ip or 2. IP of the default bridge network and is added to the /etc/hosts file

(t *testing.T)

// 2. IP of the default bridge network
// and is added to the /etc/hosts file
func TestDaemonHostGatewayIP(t *testing.T) {
	skip.If(t, testEnv.IsRemoteDaemon)
	skip.If(t, testEnv.DaemonInfo.OSType == "windows")
	t.Parallel()

	ctx := testutil.StartSpan(baseContext, t)

	// Verify the IP in /etc/hosts is same as host-gateway-ip
	d := daemon.New(t)
	// Verify the IP in /etc/hosts is same as the default bridge's IP
	d.StartWithBusybox(ctx, t, "--iptables=false", "--ip6tables=false")
	c := d.NewClientT(t)
	cID := container.Run(ctx, t, c,
		container.WithExtraHost("host.docker.internal:host-gateway"),
	)
	res, err := container.Exec(ctx, c, cID, []string{"cat", "/etc/hosts"})
	assert.NilError(t, err)
	assert.Assert(t, is.Len(res.Stderr(), 0))
	assert.Equal(t, 0, res.ExitCode)
	resp, err := c.NetworkInspect(ctx, "bridge", client.NetworkInspectOptions{})
	assert.NilError(t, err)
	assert.Check(t, is.Contains(res.Stdout(), resp.Network.IPAM.Config[0].Gateway.String()))
	c.ContainerRemove(ctx, cID, client.ContainerRemoveOptions{Force: true})
	d.Stop(t)

	// Verify the IP in /etc/hosts is same as host-gateway-ip
	d.StartWithBusybox(ctx, t, "--iptables=false", "--ip6tables=false", "--host-gateway-ip=6.7.8.9")
	cID = container.Run(ctx, t, c,
		container.WithExtraHost("host.docker.internal:host-gateway"),
	)
	res, err = container.Exec(ctx, c, cID, []string{"cat", "/etc/hosts"})
	assert.NilError(t, err)
	assert.Assert(t, is.Len(res.Stderr(), 0))
	assert.Equal(t, 0, res.ExitCode)
	assert.Check(t, is.Contains(res.Stdout(), "6.7.8.9"))
	c.ContainerRemove(ctx, cID, client.ContainerRemoveOptions{Force: true})
	d.Stop(t)
}

// TestRestartDaemonWithRestartingContainer simulates a case where a container is in "restarting" state when
// dockerd is killed (due to machine reset or something else).