syncthing/vendor/gopkg.in/urfave/cli.v1/altsrc/map_input_source.go
Jakob Borg 916ec63af6 cmd/stdiscosrv: New discovery server (fixes #4618)
This is a new revision of the discovery server. Relevant changes and
non-changes:

- Protocol towards clients is unchanged.

- Recommended large scale design is still to be deployed nehind nginx (I
  tested, and it's still a lot faster at terminating TLS).

- Database backend is leveldb again, only. It scales enough, is easy to
  setup, and we don't need any backend to take care of.

- Server supports replication. This is a simple TCP channel - protect it
  with a firewall when deploying over the internet. (We deploy this within
  the same datacenter, and with firewall.) Any incoming client announces
  are sent over the replication channel(s) to other peer discosrvs.
  Incoming replication changes are applied to the database as if they came
  from clients, but without the TLS/certificate overhead.

- Metrics are exposed using the prometheus library, when enabled.

- The database values and replication protocol is protobuf, because JSON
  was quite CPU intensive when I tried that and benchmarked it.

- The "Retry-After" value for failed lookups gets slowly increased from
  a default of 120 seconds, by 5 seconds for each failed lookup,
  independently by each discosrv. This lowers the query load over time for
  clients that are never seen. The Retry-After maxes out at 3600 after a
  couple of weeks of this increase. The number of failed lookups is
  stored in the database, now and then (avoiding making each lookup a
  database put).

All in all this means clients can be pointed towards a cluster using
just multiple A / AAAA records to gain both load sharing and redundancy
(if one is down, clients will talk to the remaining ones).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
2018-01-14 08:52:31 +00:00

263 lines
7.2 KiB
Go

package altsrc
import (
"fmt"
"reflect"
"strings"
"time"
"gopkg.in/urfave/cli.v1"
)
// MapInputSource implements InputSourceContext to return
// data from the map that is loaded.
type MapInputSource struct {
valueMap map[interface{}]interface{}
}
// nestedVal checks if the name has '.' delimiters.
// If so, it tries to traverse the tree by the '.' delimited sections to find
// a nested value for the key.
func nestedVal(name string, tree map[interface{}]interface{}) (interface{}, bool) {
if sections := strings.Split(name, "."); len(sections) > 1 {
node := tree
for _, section := range sections[:len(sections)-1] {
if child, ok := node[section]; !ok {
return nil, false
} else {
if ctype, ok := child.(map[interface{}]interface{}); !ok {
return nil, false
} else {
node = ctype
}
}
}
if val, ok := node[sections[len(sections)-1]]; ok {
return val, true
}
}
return nil, false
}
// Int returns an int from the map if it exists otherwise returns 0
func (fsm *MapInputSource) Int(name string) (int, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(int)
if !isType {
return 0, incorrectTypeForFlagError(name, "int", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(int)
if !isType {
return 0, incorrectTypeForFlagError(name, "int", nestedGenericValue)
}
return otherValue, nil
}
return 0, nil
}
// Duration returns a duration from the map if it exists otherwise returns 0
func (fsm *MapInputSource) Duration(name string) (time.Duration, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(time.Duration)
if !isType {
return 0, incorrectTypeForFlagError(name, "duration", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(time.Duration)
if !isType {
return 0, incorrectTypeForFlagError(name, "duration", nestedGenericValue)
}
return otherValue, nil
}
return 0, nil
}
// Float64 returns an float64 from the map if it exists otherwise returns 0
func (fsm *MapInputSource) Float64(name string) (float64, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(float64)
if !isType {
return 0, incorrectTypeForFlagError(name, "float64", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(float64)
if !isType {
return 0, incorrectTypeForFlagError(name, "float64", nestedGenericValue)
}
return otherValue, nil
}
return 0, nil
}
// String returns a string from the map if it exists otherwise returns an empty string
func (fsm *MapInputSource) String(name string) (string, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(string)
if !isType {
return "", incorrectTypeForFlagError(name, "string", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(string)
if !isType {
return "", incorrectTypeForFlagError(name, "string", nestedGenericValue)
}
return otherValue, nil
}
return "", nil
}
// StringSlice returns an []string from the map if it exists otherwise returns nil
func (fsm *MapInputSource) StringSlice(name string) ([]string, error) {
otherGenericValue, exists := fsm.valueMap[name]
if !exists {
otherGenericValue, exists = nestedVal(name, fsm.valueMap)
if !exists {
return nil, nil
}
}
otherValue, isType := otherGenericValue.([]interface{})
if !isType {
return nil, incorrectTypeForFlagError(name, "[]interface{}", otherGenericValue)
}
var stringSlice = make([]string, 0, len(otherValue))
for i, v := range otherValue {
stringValue, isType := v.(string)
if !isType {
return nil, incorrectTypeForFlagError(fmt.Sprintf("%s[%d]", name, i), "string", v)
}
stringSlice = append(stringSlice, stringValue)
}
return stringSlice, nil
}
// IntSlice returns an []int from the map if it exists otherwise returns nil
func (fsm *MapInputSource) IntSlice(name string) ([]int, error) {
otherGenericValue, exists := fsm.valueMap[name]
if !exists {
otherGenericValue, exists = nestedVal(name, fsm.valueMap)
if !exists {
return nil, nil
}
}
otherValue, isType := otherGenericValue.([]interface{})
if !isType {
return nil, incorrectTypeForFlagError(name, "[]interface{}", otherGenericValue)
}
var intSlice = make([]int, 0, len(otherValue))
for i, v := range otherValue {
intValue, isType := v.(int)
if !isType {
return nil, incorrectTypeForFlagError(fmt.Sprintf("%s[%d]", name, i), "int", v)
}
intSlice = append(intSlice, intValue)
}
return intSlice, nil
}
// Generic returns an cli.Generic from the map if it exists otherwise returns nil
func (fsm *MapInputSource) Generic(name string) (cli.Generic, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(cli.Generic)
if !isType {
return nil, incorrectTypeForFlagError(name, "cli.Generic", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(cli.Generic)
if !isType {
return nil, incorrectTypeForFlagError(name, "cli.Generic", nestedGenericValue)
}
return otherValue, nil
}
return nil, nil
}
// Bool returns an bool from the map otherwise returns false
func (fsm *MapInputSource) Bool(name string) (bool, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(bool)
if !isType {
return false, incorrectTypeForFlagError(name, "bool", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(bool)
if !isType {
return false, incorrectTypeForFlagError(name, "bool", nestedGenericValue)
}
return otherValue, nil
}
return false, nil
}
// BoolT returns an bool from the map otherwise returns true
func (fsm *MapInputSource) BoolT(name string) (bool, error) {
otherGenericValue, exists := fsm.valueMap[name]
if exists {
otherValue, isType := otherGenericValue.(bool)
if !isType {
return true, incorrectTypeForFlagError(name, "bool", otherGenericValue)
}
return otherValue, nil
}
nestedGenericValue, exists := nestedVal(name, fsm.valueMap)
if exists {
otherValue, isType := nestedGenericValue.(bool)
if !isType {
return true, incorrectTypeForFlagError(name, "bool", nestedGenericValue)
}
return otherValue, nil
}
return true, nil
}
func incorrectTypeForFlagError(name, expectedTypeName string, value interface{}) error {
valueType := reflect.TypeOf(value)
valueTypeName := ""
if valueType != nil {
valueTypeName = valueType.Name()
}
return fmt.Errorf("Mismatched type for flag '%s'. Expected '%s' but actual is '%s'", name, expectedTypeName, valueTypeName)
}