open-consul/agent/translate_addr.go

63 lines
2.4 KiB
Go

package agent
import (
"fmt"
"github.com/hashicorp/consul/agent/structs"
)
// TranslateAddress is used to provide the final, translated address for a node,
// depending on how the agent and the other node are configured. The dc
// parameter is the dc the datacenter this node is from.
func (a *Agent) TranslateAddress(dc string, addr string, taggedAddresses map[string]string) string {
if a.config.TranslateWANAddrs && (a.config.Datacenter != dc) {
wanAddr := taggedAddresses["wan"]
if wanAddr != "" {
addr = wanAddr
}
}
return addr
}
// TranslateAddresses translates addresses in the given structure into the
// final, translated address, depending on how the agent and the other node are
// configured. The dc parameter is the datacenter this structure is from.
func (a *Agent) TranslateAddresses(dc string, subj interface{}) {
// CAUTION - SUBTLE! An agent running on a server can, in some cases,
// return pointers directly into the immutable state store for
// performance (it's via the in-memory RPC mechanism). It's never safe
// to modify those values, so we short circuit here so that we never
// update any structures that are from our own datacenter. This works
// for address translation because we *never* need to translate local
// addresses, but this is super subtle, so we've piped all the in-place
// address translation into this function which makes sure this check is
// done. This also happens to skip looking at any of the incoming
// structure for the common case of not needing to translate, so it will
// skip a lot of work if no translation needs to be done.
if !a.config.TranslateWANAddrs || (a.config.Datacenter == dc) {
return
}
// Translate addresses in-place, subject to the condition checked above
// which ensures this is safe to do since we are operating on a local
// copy of the data.
switch v := subj.(type) {
case structs.CheckServiceNodes:
for _, entry := range v {
entry.Node.Address = a.TranslateAddress(dc, entry.Node.Address, entry.Node.TaggedAddresses)
}
case *structs.Node:
v.Address = a.TranslateAddress(dc, v.Address, v.TaggedAddresses)
case structs.Nodes:
for _, node := range v {
node.Address = a.TranslateAddress(dc, node.Address, node.TaggedAddresses)
}
case structs.ServiceNodes:
for _, entry := range v {
entry.Address = a.TranslateAddress(dc, entry.Address, entry.TaggedAddresses)
}
default:
panic(fmt.Errorf("Unhandled type passed to address translator: %#v", subj))
}
}