add helpers to config type for hosts

internal/config/config_type.go

@@ -4,7 +4,9 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"sort"
 
+	"github.com/cli/cli/internal/ghinstance"
 	"gopkg.in/yaml.v3"
 )
 
@@ -14,6 +16,8 @@ const defaultGitProtocol = "https"
 type Config interface {
 	Get(string, string) (string, error)
 	Set(string, string, string) error
+	UnsetHost(string)
+	Hosts() ([]string, error)
 	Aliases() (*AliasConfig, error)
 	Write() error
 }
@@ -29,7 +33,7 @@ type HostConfig struct {
 
 // This type implements a low-level get/set config that is backed by an in-memory tree of Yaml
 // nodes. It allows us to interact with a yaml-based config programmatically, preserving any
-// comments that were present when the yaml waas parsed.
+// comments that were present when the yaml was parsed.
 type ConfigMap struct {
 	Root *yaml.Node
 }
@@ -236,6 +240,20 @@ func (c *fileConfig) Set(hostname, key, value string) error {
 	}
 }
 
+func (c *fileConfig) UnsetHost(hostname string) {
+	if hostname == "" {
+		return
+	}
+
+	hostsEntry, err := c.FindEntry("hosts")
+	if err != nil {
+		return
+	}
+
+	cm := ConfigMap{hostsEntry.ValueNode}
+	cm.RemoveEntry(hostname)
+}
+
 func (c *fileConfig) configForHost(hostname string) (*HostConfig, error) {
 	hosts, err := c.hostEntries()
 	if err != nil {
@@ -357,6 +375,23 @@ func (c *fileConfig) hostEntries() ([]*HostConfig, error) {
 	return hostConfigs, nil
 }
 
+// Hosts returns a list of all known hostnames configred in hosts.yml
+func (c *fileConfig) Hosts() ([]string, error) {
+	entries, err := c.hostEntries()
+	if err != nil {
+		return nil, err
+	}
+
+	hostnames := []string{}
+	for _, entry := range entries {
+		hostnames = append(hostnames, entry.Host)
+	}
+
+	sort.SliceStable(hostnames, func(i, j int) bool { return hostnames[i] == ghinstance.Default() })
+
+	return hostnames, nil
+}
+
 func (c *fileConfig) makeConfigForHost(hostname string) *HostConfig {
 	hostRoot := &yaml.Node{Kind: yaml.MappingNode}
 	hostCfg := &HostConfig{