chore: cleanup error output for "coder sh" (#214)

Author: cmoog

Diff for: internal/cmd/ceapi.go

@@ -58,29 +58,37 @@ func getEnvs(ctx context.Context, client *coder.Client, email string) ([]coder.E
 	return allEnvs, nil
 }
 
-// findEnv returns a single environment by name (if it exists.).
-func findEnv(ctx context.Context, client *coder.Client, envName, userEmail string) (*coder.Environment, error) {
+// searchForEnv searches a user's environments to find the specified envName. If none is found, the haystack of
+// environment names is returned.
+func searchForEnv(ctx context.Context, client *coder.Client, envName, userEmail string) (_ *coder.Environment, haystack []string, _ error) {
 	envs, err := getEnvs(ctx, client, userEmail)
 	if err != nil {
-		return nil, xerrors.Errorf("get environments: %w", err)
+		return nil, nil, xerrors.Errorf("get environments: %w", err)
 	}
 
 	// NOTE: We don't know in advance where we will find the env, so we can't pre-alloc.
-	var found []string
 	for _, env := range envs {
 		if env.Name == envName {
-			return &env, nil
+			return &env, nil, nil
 		}
 		// Keep track of what we found for the logs.
-		found = append(found, env.Name)
+		haystack = append(haystack, env.Name)
 	}
+	return nil, haystack, coder.ErrNotFound
+}
 
-	return nil, clog.Fatal(
-		"failed to find environment",
-		fmt.Sprintf("environment %q not found in %q", envName, found),
-		clog.BlankLine,
-		clog.Tipf("run \"coder envs ls\" to view your environments"),
-	)
+// findEnv returns a single environment by name (if it exists.).
+func findEnv(ctx context.Context, client *coder.Client, envName, userEmail string) (*coder.Environment, error) {
+	env, haystack, err := searchForEnv(ctx, client, envName, userEmail)
+	if err != nil {
+		return nil, clog.Fatal(
+			"failed to find environment",
+			fmt.Sprintf("environment %q not found in %q", envName, haystack),
+			clog.BlankLine,
+			clog.Tipf("run \"coder envs ls\" to view your environments"),
+		)
+	}
+	return env, nil
 }
 
 type findImgConf struct {

Diff for: internal/cmd/shell.go

@@ -41,12 +41,33 @@ func getEnvsForCompletion(user string) func(cmd *cobra.Command, args []string, t
 	}
 }
 
+// special handling for the common case of "coder sh" input without a positional argument.
+func shValidArgs(cmd *cobra.Command, args []string) error {
+	ctx := cmd.Context()
+	if err := cobra.MinimumNArgs(1)(cmd, args); err != nil {
+		client, err := newClient(ctx)
+		if err != nil {
+			return clog.Error("missing [environment_name] argument")
+		}
+		_, haystack, err := searchForEnv(ctx, client, "", coder.Me)
+		if err != nil {
+			return clog.Error("missing [environment_name] argument",
+				fmt.Sprintf("specify one of %q", haystack),
+				clog.BlankLine,
+				clog.Tipf("run \"coder envs ls\" to view your environments"),
+			)
+		}
+		return clog.Error("missing [environment_name] argument")
+	}
+	return nil
+}
+
 func shCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:                "sh [environment_name] [<command [args...]>]",
 		Short:              "Open a shell and execute commands in a Coder environment",
 		Long:               "Execute a remote command on the environment\\nIf no command is specified, the default shell is opened.",
-		Args:               cobra.MinimumNArgs(1),
+		Args:               shValidArgs,
 		DisableFlagParsing: true,
 		ValidArgsFunction:  getEnvsForCompletion(coder.Me),
 		RunE:               shell,