account: use dwshell with more than one DWService account

README.md

@@ -160,7 +160,8 @@ the session without any of this. To supply a code non-interactively, see
 | Command | Description |
 |---|---|
 | `dwshell login [--user U] [--no-trusted]` | Authenticate and persist the session (and, by default, a trusted device). |
-| `dwshell logout` | Deregister the trusted device and forget local credentials. |
+| `dwshell logout [--all]` | Deregister the trusted device and forget local credentials. |
+| `dwshell account list\|default\|rm` | Manage accounts, once you log in with more than one. |
 | `dwshell list [--json]` | List machines with OS, online state, and owned/shared. |
 | `dwshell <agent>` | Open an interactive shell. |
 | `dwshell <agent> -c "cmd"` | Run a command non-interactively; exit code is propagated. |
@@ -247,6 +248,38 @@ the download page is where the licence is accepted. The agent's unattended mode
 it — an install attempted that way answers *"Silent installation forbidden.
 Please contact the support."*
 
+### More than one account
+
+Log in twice with different emails and dwshell keeps both. Until you do, nothing
+changes: with a single account there is no default to think about and no flag to
+pass, and an existing configuration is carried over the first time dwshell saves
+anything.
+
+```sh
+$ dwshell login --user [email protected]     # the email is the account's identity
+$ dwshell account list
+[email protected]  (default)
+[email protected]
+
+$ dwshell list                              # the default account
+$ dwshell list --account [email protected]   # the other one
+$ [email protected] dwshell list      # for a whole session
+```
+
+The first account you log in with becomes the default; change it with
+`dwshell account default <email>`. Logging in again with an email already
+registered just refreshes that account.
+
+`dwshell logout` forgets the selected account, `--all` forgets every one, and
+`dwshell account rm <email>` forgets a named one — each deregistering that
+account's trusted device, and each asking for confirmation unless you pass
+`--yes`. Remove the default and, if a single account is left, it takes over; if
+several remain, dwshell asks you to pick one rather than choosing for you.
+
+Flags follow their subcommand — `dwshell list --account …`, not
+`dwshell --account … list` — except in the shell shortcut, where
+`dwshell --account … myserver` works too.
+
 #### Agent name vs subcommand
 
 `dwshell <agent>` is a convenience shortcut: the first argument is treated as an

cmd/dwshell/account.go

@@ -0,0 +1,172 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/porech/dwshell/internal/client"
+	"github.com/porech/dwshell/internal/config"
+	"github.com/porech/dwshell/internal/term"
+)
+
+// cmdAccount dispatches `dwshell account <verb>`, which exists only for people
+// who log in with more than one account. With a single account there is nothing
+// here worth running.
+func cmdAccount(ctx context.Context, args []string) int {
+	if len(args) == 0 {
+		return fail("usage: dwshell account <list|default|rm>")
+	}
+	switch args[0] {
+	case "list":
+		return cmdAccountList(args[1:])
+	case "default":
+		return cmdAccountDefault(args[1:])
+	case "rm":
+		return cmdAccountRemove(ctx, args[1:])
+	default:
+		return fail("unknown account subcommand %q", args[0])
+	}
+}
+
+// accountJSON is the --json shape of one registered account.
+type accountJSON struct {
+	User    string `json:"user"`
+	Default bool   `json:"default"`
+}
+
+func cmdAccountList(args []string) int {
+	fs := newFlags("account list")
+	var configPath string
+	asJSON := false
+	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.BoolVar(&asJSON, "json", false, "machine-readable output")
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	cfg, err := config.Load(configPath)
+	if err != nil {
+		return fail("%v", err)
+	}
+	if len(cfg.Accounts) == 0 {
+		return fail("%v", config.ErrNoAccounts)
+	}
+	if asJSON {
+		out := make([]accountJSON, 0, len(cfg.Accounts))
+		for _, a := range cfg.Accounts {
+			out = append(out, accountJSON{User: a.User, Default: a.User == cfg.Default})
+		}
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		_ = enc.Encode(out)
+		return 0
+	}
+	for _, a := range cfg.Accounts {
+		name := a.User
+		if name == "" {
+			name = "(unnamed)"
+		}
+		if a.User == cfg.Default {
+			fmt.Printf("%s  (default)\n", name)
+			continue
+		}
+		fmt.Println(name)
+	}
+	return 0
+}
+
+func cmdAccountDefault(args []string) int {
+	fs := newFlags("account default")
+	var configPath string
+	fs.StringVar(&configPath, "config", "", "config file path")
+	if err := fs.Parse(args); err != nil {
+		return 2
+	}
+	if fs.NArg() != 1 {
+		return fail("usage: dwshell account default <email>")
+	}
+	cfg, err := config.Load(configPath)
+	if err != nil {
+		return fail("%v", err)
+	}
+	if err := cfg.SetDefault(fs.Arg(0)); err != nil {
+		return fail("%v", err)
+	}
+	if err := cfg.Save(); err != nil {
+		return fail("%v", err)
+	}
+	fmt.Fprintf(os.Stderr, "default account is now %s\n", fs.Arg(0))
+	return 0
+}
+
+func cmdAccountRemove(ctx context.Context, args []string) int {
+	fs := newFlags("account rm")
+	var configPath string
+	assumeYes := false
+	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.BoolVar(&assumeYes, "yes", false, "do not ask for confirmation")
+	email, flagArgs := extractPositional(args)
+	if err := fs.Parse(flagArgs); err != nil {
+		return 2
+	}
+	if email == "" {
+		return fail("usage: dwshell account rm <email> [--yes]")
+	}
+	if err := confirm(fmt.Sprintf("remove account %q and deregister its trusted device?", email),
+		assumeYes, term.IsTTY()); err != nil {
+		return fail("%v", err)
+	}
+	// Selecting the account being removed is what lets the client deregister its
+	// trusted device server-side before forgetting it locally.
+	c, err := client.New(configPath, email)
+	if err != nil {
+		return fail("%v", err)
+	}
+	if err := c.Logout(ctx); err != nil {
+		return fail("%v", err)
+	}
+	fmt.Fprintf(os.Stderr, "account %s removed\n", email)
+	return 0
+}
+
+// extractPositional pulls the first non-flag token out of a subcommand's args,
+// returning it with the flags that surrounded it. Go's flag package stops at
+// the first positional, so `account rm a@b --yes` would otherwise drop --yes;
+// this mirrors what extractAgent does for the shell shortcut.
+func extractPositional(args []string) (pos string, flagArgs []string) {
+	i := 0
+	for i < len(args) {
+		a := args[i]
+		if len(a) > 0 && a[0] == '-' {
+			flagArgs = append(flagArgs, a)
+			if !containsEq(a) && valueFlags[trimDashes(a)] && i+1 < len(args) {
+				i++
+				flagArgs = append(flagArgs, args[i])
+			}
+			i++
+			continue
+		}
+		return a, append(flagArgs, args[i+1:]...)
+	}
+	return "", flagArgs
+}
+
+// confirm gates a change that cannot be undone. With a terminal it asks; with
+// none — a script, a CI job — it refuses unless the caller passed --yes, so
+// automation cannot drop an account by accident.
+func confirm(prompt string, assumeYes, interactive bool) error {
+	if assumeYes {
+		return nil
+	}
+	if !interactive {
+		return fmt.Errorf("%s refusing without a terminal; pass --yes to proceed", prompt)
+	}
+	fmt.Fprintf(os.Stderr, "%s [y/N] ", prompt)
+	var answer string
+	_, _ = fmt.Fscanln(os.Stdin, &answer)
+	if answer != "y" && answer != "Y" {
+		return fmt.Errorf("cancelled")
+	}
+	return nil
+}

cmd/dwshell/agent.go

@@ -62,32 +62,6 @@ func printAgentJSON(a agentJSON) {
 	_ = enc.Encode(a)
 }
 
-// agentValueFlags are the `agent` subcommand flags that consume a following
-// value token, so a positional can be pulled out from among them.
-var agentValueFlags = map[string]bool{"config": true, "description": true, "group": true}
-
-// extractPositional pulls the first non-flag token out of a subcommand's args,
-// returning it with the flags that surrounded it. Go's flag package stops at
-// the first positional, so `agent create NAME --json` would otherwise silently
-// drop --json; this mirrors what extractAgent does for the shell shortcut.
-func extractPositional(args []string) (pos string, flagArgs []string) {
-	i := 0
-	for i < len(args) {
-		a := args[i]
-		if len(a) > 0 && a[0] == '-' {
-			flagArgs = append(flagArgs, a)
-			if !containsEq(a) && agentValueFlags[trimDashes(a)] && i+1 < len(args) {
-				i++
-				flagArgs = append(flagArgs, args[i])
-			}
-			i++
-			continue
-		}
-		return a, append(flagArgs, args[i+1:]...)
-	}
-	return "", flagArgs
-}
-
 // cmdAgentManage dispatches the `dwshell agent <verb>` family. It is separate
 // from cmdAgent, which is the shell shortcut for `dwshell <agent>`.
 func cmdAgentManage(ctx context.Context, args []string) int {
@@ -112,9 +86,11 @@ func cmdAgentManage(ctx context.Context, args []string) int {
 
 func cmdAgentCreate(ctx context.Context, args []string) int {
 	fs := newFlags("agent create")
+	var account string
 	var configPath, description, group string
 	asJSON := false
 	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.StringVar(&account, "account", "", "account to use when several are logged in")
 	fs.StringVar(&description, "description", "", "free-text description")
 	fs.StringVar(&group, "group", "", "existing group to place the agent in")
 	fs.BoolVar(&asJSON, "json", false, "machine-readable output")
@@ -126,7 +102,7 @@ func cmdAgentCreate(ctx context.Context, args []string) int {
 		return fail("usage: dwshell agent create <name> [--group G] [--description D] [--json]")
 	}
 
-	c, err := client.New(configPath)
+	c, err := client.New(configPath, account)
 	if err != nil {
 		return fail("%v", err)
 	}
@@ -163,25 +139,6 @@ func cmdAgentCreate(ctx context.Context, args []string) int {
 	return 0
 }
 
-// confirm gates a change that cannot be undone. With a terminal it asks; with
-// none — a script, a CI job — it refuses unless the caller passed --yes, so
-// automation cannot delete a machine or invalidate a code by accident.
-func confirm(prompt string, assumeYes, interactive bool) error {
-	if assumeYes {
-		return nil
-	}
-	if !interactive {
-		return fmt.Errorf("%s refusing without a terminal; pass --yes to proceed", prompt)
-	}
-	fmt.Fprintf(os.Stderr, "%s [y/N] ", prompt)
-	var answer string
-	_, _ = fmt.Fscanln(os.Stdin, &answer)
-	if answer != "y" && answer != "Y" {
-		return fmt.Errorf("cancelled")
-	}
-	return nil
-}
-
 // resolveOwnAgent finds an agent by name or id and refuses anything these
 // commands cannot act on: a share is someone else's agent.
 func resolveOwnAgent(machines []remote.Machine, query string) (*remote.Machine, error) {
@@ -209,8 +166,8 @@ func agentCodeFor(m *remote.Machine) error {
 
 // agentSession resolves an owned agent and hands back a session for acting on
 // the account, which every subcommand below needs.
-func agentSession(ctx context.Context, configPath, query string) (*remote.Machine, *client.Client, *session.Session, int) {
-	c, err := client.New(configPath)
+func agentSession(ctx context.Context, configPath, account, query string) (*remote.Machine, *client.Client, *session.Session, int) {
+	c, err := client.New(configPath, account)
 	if err != nil {
 		return nil, nil, nil, fail("%v", err)
 	}
@@ -231,9 +188,11 @@ func agentSession(ctx context.Context, configPath, query string) (*remote.Machin
 
 func cmdAgentCode(ctx context.Context, args []string) int {
 	fs := newFlags("agent code")
+	var account string
 	var configPath string
 	asJSON := false
 	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.StringVar(&account, "account", "", "account to use when several are logged in")
 	fs.BoolVar(&asJSON, "json", false, "machine-readable output")
 	name, flagArgs := extractPositional(args)
 	if err := fs.Parse(flagArgs); err != nil {
@@ -242,7 +201,7 @@ func cmdAgentCode(ctx context.Context, args []string) int {
 	if name == "" {
 		return fail("usage: dwshell agent code <agent> [--json]")
 	}
-	m, _, _, code := agentSession(ctx, configPath, name)
+	m, _, _, code := agentSession(ctx, configPath, account, name)
 	if m == nil {
 		return code
 	}
@@ -264,9 +223,10 @@ func cmdAgentCode(ctx context.Context, args []string) int {
 // and what they warn about: both are irreversible and both confirm first.
 func cmdAgentLifecycle(ctx context.Context, args []string, verb string) int {
 	fs := newFlags("agent " + verb)
-	var configPath string
+	var configPath, account string
 	assumeYes := false
 	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.StringVar(&account, "account", "", "account to use when several are logged in")
 	fs.BoolVar(&assumeYes, "yes", false, "do not ask for confirmation")
 	name, flagArgs := extractPositional(args)
 	if err := fs.Parse(flagArgs); err != nil {
@@ -275,7 +235,7 @@ func cmdAgentLifecycle(ctx context.Context, args []string, verb string) int {
 	if name == "" {
 		return fail("usage: dwshell agent %s <agent> [--yes]", verb)
 	}
-	m, _, sess, code := agentSession(ctx, configPath, name)
+	m, _, sess, code := agentSession(ctx, configPath, account, name)
 	if m == nil {
 		return code
 	}
@@ -300,7 +260,7 @@ func cmdAgentLifecycle(ctx context.Context, args []string, verb string) int {
 	}
 	// The command acknowledges without echoing the record, so the new code is
 	// read back from the listing.
-	c, err := client.New(configPath)
+	c, err := client.New(configPath, account)
 	if err != nil {
 		return fail("%v", err)
 	}
@@ -318,9 +278,11 @@ func cmdAgentLifecycle(ctx context.Context, args []string, verb string) int {
 
 func cmdAgentGroup(ctx context.Context, args []string) int {
 	fs := newFlags("agent group")
+	var account string
 	var configPath string
 	none := false
 	fs.StringVar(&configPath, "config", "", "config file path")
+	fs.StringVar(&account, "account", "", "account to use when several are logged in")
 	fs.BoolVar(&none, "none", false, "remove the agent from its group")
 	name, flagArgs := extractPositional(args)
 	if err := fs.Parse(flagArgs); err != nil {
@@ -337,7 +299,7 @@ func cmdAgentGroup(ctx context.Context, args []string) int {
 		return fail("usage: dwshell agent group <agent> <group>   (or --none)")
 	}
 
-	m, _, sess, code := agentSession(ctx, configPath, name)
+	m, _, sess, code := agentSession(ctx, configPath, account, name)
 	if m == nil {
 		return code
 	}