consul: use the Near field instead of PreferLocal

This commit is contained in:
Ryan Uber 2016-06-21 12:39:40 -07:00
parent 89fe991ab7
commit 114e57fff1
6 changed files with 58 additions and 33 deletions

View File

@ -531,13 +531,7 @@ func (s *HTTPServer) parseToken(req *http.Request, token *string) {
// DC in the request, if given, or else the agent's DC.
func (s *HTTPServer) parseSource(req *http.Request, source *structs.QuerySource) {
s.parseDC(req, &source.Datacenter)
if node := req.URL.Query().Get("near"); node != "" {
if node == "_agent" {
source.Node = s.agent.config.NodeName
} else {
source.Node = node
}
}
source.Node = req.URL.Query().Get("near")
}
// parse is a convenience method for endpoints that need

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@ -382,18 +382,6 @@ func TestParseSource(t *testing.T) {
if source.Datacenter != "foo" || source.Node != "bob" {
t.Fatalf("bad: %v", source)
}
// The magic "_agent" node name will use the agent's local node name.
req, err = http.NewRequest("GET",
"/v1/catalog/nodes?near=_agent", nil)
if err != nil {
t.Fatalf("err: %v", err)
}
source = structs.QuerySource{}
srv.parseSource(req, &source)
if source.Datacenter != "dc1" || source.Node != srv.agent.config.NodeName {
t.Fatalf("bad: %v", source)
}
}
func TestParseWait(t *testing.T) {

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@ -279,6 +279,7 @@ func TestPreparedQuery_Execute(t *testing.T) {
m.executeFn = func(args *structs.PreparedQueryExecuteRequest, reply *structs.PreparedQueryExecuteResponse) error {
expected := &structs.PreparedQueryExecuteRequest{
Origin: srv.agent.config.NodeName,
Datacenter: "dc1",
QueryIDOrName: "my-id",
Limit: 5,
@ -350,6 +351,7 @@ func TestPreparedQuery_Explain(t *testing.T) {
m.explainFn = func(args *structs.PreparedQueryExecuteRequest, reply *structs.PreparedQueryExplainResponse) error {
expected := &structs.PreparedQueryExecuteRequest{
Origin: srv.agent.config.NodeName,
Datacenter: "dc1",
QueryIDOrName: "my-id",
Limit: 5,

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@ -368,12 +368,35 @@ func (p *PreparedQuery) Execute(args *structs.PreparedQueryExecuteRequest,
// Shuffle the results in case coordinates are not available if they
// requested an RTT sort.
reply.Nodes.Shuffle()
if err := p.srv.sortNodesByDistanceFrom(args.Source, reply.Nodes); err != nil {
// Get the source to sort by. This can be passed in by the requestor, or
// pre-defined using the Near parameter in the prepared query. If the
// near parameter was defined, that will be preferred.
sortFrom := args.Source
if query.Service.Near != "" {
sortFrom = structs.QuerySource{
Datacenter: args.Datacenter,
Node: query.Service.Near,
}
}
// Respect the magic "_agent" flag.
preferLocal := false
if sortFrom.Node == "_agent" {
preferLocal = true
sortFrom.Node = args.Origin
}
// Perform the distance sort
if err := p.srv.sortNodesByDistanceFrom(sortFrom, reply.Nodes); err != nil {
return err
}
// Prefer the local service if it exists and is in the set.
if query.Service.PreferLocal {
// Nodes cannot be any "closer" than localhost, so this special case ensures
// the local node is returned first if it is present in the result. This
// allows the local agent to be preferred even when network coordinates are
// not enabled.
if preferLocal {
for i, node := range reply.Nodes {
if node.Node.Node == args.Origin {
remote := append(reply.Nodes[:i], reply.Nodes[i+1:]...)

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@ -1609,7 +1609,7 @@ func TestPreparedQuery_Execute(t *testing.T) {
// Set the query to prefer a colocated service
query.Op = structs.PreparedQueryUpdate
query.Query.Service.PreferLocal = true
query.Query.Service.Near = "_agent"
if err := msgpackrpc.CallWithCodec(codec1, "PreparedQuery.Apply", &query, &query.Query.ID); err != nil {
t.Fatalf("err: %v", err)
}
@ -1630,7 +1630,6 @@ func TestPreparedQuery_Execute(t *testing.T) {
if err := msgpackrpc.CallWithCodec(codec1, "PreparedQuery.Execute", &req, &reply); err != nil {
t.Fatalf("err: %v", err)
}
if n := len(reply.Nodes); n != 10 {
t.Fatalf("expect 10 nodes, got: %d", n)
}
@ -1640,8 +1639,27 @@ func TestPreparedQuery_Execute(t *testing.T) {
}
}
// Falls back to remote nodes if service is not available locally
{
req := structs.PreparedQueryExecuteRequest{
Origin: "not-in-result",
Datacenter: "dc1",
QueryIDOrName: query.Query.ID,
QueryOptions: structs.QueryOptions{Token: execToken},
}
var reply structs.PreparedQueryExecuteResponse
if err := msgpackrpc.CallWithCodec(codec1, "PreparedQuery.Execute", &req, &reply); err != nil {
t.Fatalf("err: %v", err)
}
if n := len(reply.Nodes); n != 10 {
t.Fatalf("expect 10 nodes, got: %d", n)
}
}
// Remove local preference.
query.Query.Service.PreferLocal = false
query.Query.Service.Near = ""
if err := msgpackrpc.CallWithCodec(codec1, "PreparedQuery.Apply", &query, &query.Query.ID); err != nil {
t.Fatalf("err:% v", err)
}

View File

@ -34,10 +34,10 @@ type ServiceQuery struct {
// discarded)
OnlyPassing bool
// If PreferLocal is true, the local agent will be checked for a local
// copy of the service before continuing to remote machines. This is
// useful to prefer colocated services but fall back when unavailable.
PreferLocal bool
// Near allows the query to always prefer the node nearest the given
// node. If the node does not exist, results are returned in their
// normal randomly-shuffled order.
Near string
// Tags are a set of required and/or disallowed tags. If a tag is in
// this list it must be present. If the tag is preceded with "!" then
@ -168,10 +168,6 @@ func (q *PreparedQuerySpecificRequest) RequestDatacenter() string {
// PreparedQueryExecuteRequest is used to execute a prepared query.
type PreparedQueryExecuteRequest struct {
// Origin is used to carry around a reference to the node which
// is executing the query on behalf of the client.
Origin string
// Datacenter is the target this request is intended for.
Datacenter string
@ -182,6 +178,10 @@ type PreparedQueryExecuteRequest struct {
// Limit will trim the resulting list down to the given limit.
Limit int
// Origin is used to carry around a reference to the node which
// is executing the query on behalf of the client.
Origin string
// Source is used to sort the results relative to a given node using
// network coordinates.
Source QuerySource