STRLCPY/cdebug

Port forwarding WiP
Ivan Velichko committed 2 years ago

8bb5d5f9

1 parent f20510b6

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cmd/portforward/portforward.go

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2	2
3	3		import (
4	4		"context"
	5	+	"errors"
5	6		"fmt"
6	7		"io"
	8	+	"strings"
7	9
8	10		"github.com/docker/docker/api/types"
9	11		"github.com/docker/docker/api/types/container"
		skipped 15 lines
25	27		// Possible options (kinda sorta as in ssh -L):
26	28		// - TARGET_PORT # binds TARGET_IP:TARGET_PORT to a random port on localhost
27	29		// - TARGET_IP:TARGET_PORT # The second form is needed to:
28		-	// # 1) allow target's localhost ports expose
29		-	// # 2) specify a concrete IP if a multi-network target listens on 0.0.0.0
	30	+	// # 1) allow exposing target's localhost ports
	31	+	// # 2) specify a concrete IP for a multi-network target
30	32		//
31	33		// - LOCAL_PORT:TARGET_PORT # binds TARGET_IP:TARGET_PORT to LOCAL_PORT on localhost
32	34		// - LOCAL_PORT:TARGET_IP:TARGET_PORT
33	35		//
34		-	// - LOCAL_IP:LOCAL_PORT:TARGET_PORT # binds TARGET_IP:TARGET_PORT to LOCAL_PORT on LOCAL_IP
	36	+	// - LOCAL_IP:LOCAL_PORT:TARGET_PORT # similar to LOCAL_PORT:TARGET_PORT but LOCAL_IP is used instead of localhost
35	37		// - LOCAL_IP:LOCAL_PORT:TARGET_IP:TARGET_PORT
36	38
37	39		const (
38		-	helperImage = "nixery.dev/socat:latest"
	40	+	helperImage = "nixery.dev/shell/socat:latest"
39	41		)
40	42
41	43		type options struct {
42		-	target string
43		-	address string
44		-	ports []string
	44	+	target string
	45	+	forwardings []string
45	46		}
46	47
47	48		func NewCommand(cli cmd.CLI) *cobra.Command {
48	49		var opts options
49	50
50	51		cmd := &cobra.Command{
51		-	Use: "port-forward [OPTIONS] CONTAINER [LOCAL_PORT:]TARGET_PORT [...[LOCAL_PORT_N:]TARGET_PORT_N]",
52		-	Short: "Publish a port of an already running container (kind of)",
	52	+	Use: "port-forward CONTAINER [[LOCAL_IP:]LOCAL_PORT:]TARGET_PORT [...]",
	53	+	Short: `"Publish" one or more ports of an already running container`,
53	54		Args: cobra.MinimumNArgs(2),
54	55		RunE: func(cmd *cobra.Command, args []string) error {
55	56		opts.target = args[0]
56		-	if len(args) > 1 {
57		-	opts.ports = args[1:]
58		-	}
	57	+	opts.forwardings = args[1:]
59	58		return runPortForward(context.Background(), cli, &opts)
60	59		},
61	60		}
62	61
63		-	flags := cmd.Flags()
64		-	flags.SetInterspersed(false) // Instead of relying on --
65		-
66		-	flags.StringVar(
67		-	&opts.address,
68		-	"address",
69		-	"127.0.0.1",
70		-	"Host's interface address to bind the port to",
71		-	)
72		-
73	62		return cmd
74	63		}
75	64
		skipped 15 lines
91	80		return err
92	81		}
93	82
94		-	ports, portBindings, err := nat.ParsePortSpecs([]string{"8080:80"})
	83	+	forwardings, err := prepareForwardings(target, opts.forwardings)
95	84		if err != nil {
96	85		return err
97	86		}
98	87
99		-	contIP := target.NetworkSettings.Networks["bridge"].IPAddress
	88	+	exposedPorts, portBindings, err := nat.ParsePortSpecs(forwardings.toDockerPortSpecs())
	89	+	if err != nil {
	90	+	return err
	91	+	}
	92	+
	93	+	// TODO: Iterate over all forwardings.
100	94		resp, err := client.ContainerCreate(
101	95		ctx,
102	96		&container.Config{
103	97		Image: helperImage,
104	98		Entrypoint: []string{"socat"},
105	99		Cmd: []string{
106		-	"TCP-LISTEN:80,fork",
107		-	fmt.Sprintf("TCP-CONNECT:%s:%d", contIP, 80),
	100	+	fmt.Sprintf("TCP-LISTEN:%s,fork", forwardings[0].targetPort),
	101	+	fmt.Sprintf("TCP-CONNECT:%s:%d", forwardings[0].targetIP, forwardings[0].targetPort),
108	102		},
109		-	ExposedPorts: ports,
	103	+	ExposedPorts: exposedPorts,
110	104		},
111	105		&container.HostConfig{
112	106		AutoRemove: true,
		skipped 11 lines
124	118		return fmt.Errorf("cannot start port-forwarder container: %w", err)
125	119		}
126	120
	121	+	// TODO: Handle ctrl + C and other signals.
127	122		forwarderStatusCh, forwarderErrCh := client.ContainerWait(ctx, resp.ID, container.WaitConditionNotRunning)
128	123		// targetStatusCh, targetErrCh := client.ContainerWait(ctx, target.ID, container.WaitConditionNotRunning)
129	124		select {
		skipped 23 lines
153	148		return err
154	149		}
155	150
	151	+	type forwarding struct {
	152	+	localIP string
	153	+	localPort string
	154	+	targetIP string
	155	+	targetPort string
	156	+	}
	157	+
	158	+	type forwardingList []forwarding
	159	+
	160	+	func (list forwardingList) toDockerPortSpecs() []string {
	161	+	// ip:hostPort:containerPort \| ip::containerPort \| hostPort:containerPort \| containerPort
	162	+	var spec []string
	163	+	for _, f := range list {
	164	+	spec = append(spec, fmt.Sprintf("%s:%s:%s", f.localIP, f.localPort, f.targetPort))
	165	+	}
	166	+	return spec
	167	+	}
	168	+
	169	+	func prepareForwardings(
	170	+	target types.ContainerJSON,
	171	+	forwardings []string,
	172	+	) (forwardingList, error) {
	173	+	var list forwardingList
	174	+
	175	+	targetIP := target.NetworkSettings.Networks["bridge"].IPAddress
	176	+
	177	+	for _, f := range forwardings {
	178	+	parts := strings.Split(f, ":")
	179	+	if len(parts) == 1 {
	180	+	// Case 1: TARGET_PORT
	181	+
	182	+	if _, err := nat.ParsePort(parts[0]); err != nil {
	183	+	// TODO: Return a user-friendly error.
	184	+	return nil, err
	185	+	}
	186	+
	187	+	// TODO: if "target has more than 1 IP" return err
	188	+
	189	+	list = append(list, forwarding{
	190	+	localIP: "127.0.0.1",
	191	+	targetPort: parts[0],
	192	+	targetIP: targetIP,
	193	+	})
	194	+	continue
	195	+	}
	196	+
	197	+	if len(parts) == 2 {
	198	+	if _, err := nat.ParsePort(parts[0]); err == nil {
	199	+	// Case 2: LOCAL_PORT:TARGET_PORT
	200	+
	201	+	// TODO: if "target has more than 1 IP" return err
	202	+
	203	+	list = append(list, forwarding{
	204	+	localPort: parts[0],
	205	+	localIP: "127.0.0.1",
	206	+	targetPort: parts[1],
	207	+	targetIP: targetIP,
	208	+	})
	209	+	} else {
	210	+	// Case 3: TARGET_IP:TARGET_PORT
	211	+
	212	+	// TODO: if "parts[0] not in target IP list" return err
	213	+
	214	+	list = append(list, forwarding{
	215	+	localIP: "127.0.0.1",
	216	+	targetPort: parts[1],
	217	+	targetIP: parts[0],
	218	+	})
	219	+	}
	220	+	continue
	221	+	}
	222	+
	223	+	// TODO: other cases
	224	+	return nil, errors.New("implement me")
	225	+	}
	226	+
	227	+	return list, nil
	228	+	}
	229	+

Port forwarding WiP