Add podman farm remove command

Podman farm remove allows users to remove one or more
existing farms.

Signed-off-by: Urvashi Mohnani <umohnani@redhat.com>

cmd/podman/farm/remove.go

@@ -0,0 +1,99 @@
+package farm
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/podman/v4/cmd/podman/common"
+	"github.com/containers/podman/v4/cmd/podman/registry"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+var (
+	farmRmDescription = `Remove one or more existing farms.`
+	rmCommand         = &cobra.Command{
+		Use:               "remove [options] [FARM...]",
+		Aliases:           []string{"rm"},
+		Short:             "Remove one or more farms",
+		Long:              farmRmDescription,
+		RunE:              rm,
+		ValidArgsFunction: common.AutoCompleteFarms,
+		Example: `podman farm rm myfarm1 myfarm2
+  podman farm rm --all`,
+	}
+
+	// Temporary struct to hold cli values.
+	rmOpts = struct {
+		All bool
+	}{}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: rmCommand,
+		Parent:  farmCmd,
+	})
+	flags := rmCommand.Flags()
+	flags.BoolVarP(&rmOpts.All, "all", "a", false, "Remove all farms")
+}
+
+func rm(cmd *cobra.Command, args []string) error {
+	cfg, err := config.ReadCustomConfig()
+	if err != nil {
+		return err
+	}
+
+	if rmOpts.All {
+		cfg.Farms.List = make(map[string][]string)
+		cfg.Farms.Default = ""
+		if err := cfg.Write(); err != nil {
+			return err
+		}
+		fmt.Println("All farms have been deleted")
+		return nil
+	}
+
+	// If the --all is not set, we require at least one arg
+	if len(args) == 0 {
+		return errors.New("requires at lease 1 arg(s), received 0")
+	}
+
+	if len(cfg.Farms.List) == 0 {
+		return errors.New("no existing farms; nothing to remove")
+	}
+
+	deletedFarms := []string{}
+	for _, k := range args {
+		if _, ok := cfg.Farms.List[k]; !ok {
+			logrus.Warnf("farm %q doesn't exists; nothing to remove", k)
+			continue
+		}
+		delete(cfg.Farms.List, k)
+		deletedFarms = append(deletedFarms, k)
+		if k == cfg.Farms.Default {
+			cfg.Farms.Default = ""
+		}
+	}
+	// Return error if none of the given farms were deleted
+	if len(deletedFarms) == 0 {
+		return fmt.Errorf("failed to delete farms %q", args)
+	}
+
+	// Set a new default farm if the current default farm has been removed
+	if cfg.Farms.Default == "" && cfg.Farms.List != nil {
+		for k := range cfg.Farms.List {
+			cfg.Farms.Default = k
+			break
+		}
+	}
+	if err := cfg.Write(); err != nil {
+		return err
+	}
+
+	for _, k := range deletedFarms {
+		fmt.Printf("Farm %q deleted\n", k)
+	}
+	return nil
+}

docs/source/markdown/podman-farm-remove.1.md

@@ -0,0 +1,30 @@
+% podman-farm-remove 1
+
+## NAME
+podman\-farm\-remove - Delete one or more farms
+
+## SYNOPSIS
+**podman farm remove** [*options*] *name*
+
+**podman farm rm** [*options*] *name*
+
+## DESCRIPTION
+Delete one or more farms.
+
+## OPTIONS
+
+#### **--all**, **-a**
+
+Remove all farms.
+
+## EXAMPLE
+```
+$ podman farm remove farm1
+
+$ podman farm rm --all
+```
+## SEE ALSO
+**[podman(1)](podman.1.md)**, **[podman-farm(1)](podman-farm.1.md)**
+
+## HISTORY
+July 2023, Originally compiled by Urvashi Mohnani (umohnani at redhat dot com)s