0dfb7da610
We have seen test flakes caused by 'concurrent map read and map write', and the race detector reports the problem as well (prevent us from running some tests with -race). The root of the problem is the grpc expects resolvers to be registered at init time before any requests are made, but we were using a separate resolver for each test. This commit introduces a resolver registry. The registry is registered as the single resolver for the consul scheme. Each test uses the Authority section of the target (instead of the scheme) to identify the resolver that should be used for the test. The scheme is used for lookup, which is why it can no longer be used as the unique key. This allows us to use a lock around the map of resolvers, preventing the data race.
55 lines
1.4 KiB
Go
55 lines
1.4 KiB
Go
package resolver
|
|
|
|
import (
|
|
"fmt"
|
|
"sync"
|
|
|
|
"google.golang.org/grpc/resolver"
|
|
)
|
|
|
|
// registry of ServerResolverBuilder. This type exists because grpc requires that
|
|
// resolvers are registered globally before any requests are made. This is
|
|
// incompatible with our resolver implementation and testing strategy, which
|
|
// requires a different Resolver for each test.
|
|
type registry struct {
|
|
lock sync.RWMutex
|
|
byAuthority map[string]*ServerResolverBuilder
|
|
}
|
|
|
|
func (r *registry) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
|
|
r.lock.RLock()
|
|
defer r.lock.RUnlock()
|
|
res, ok := r.byAuthority[target.Authority]
|
|
if !ok {
|
|
return nil, fmt.Errorf("no resolver registered for %v", target.Authority)
|
|
}
|
|
return res.Build(target, cc, opts)
|
|
}
|
|
|
|
func (r *registry) Scheme() string {
|
|
return "consul"
|
|
}
|
|
|
|
var _ resolver.Builder = (*registry)(nil)
|
|
|
|
var reg = ®istry{byAuthority: make(map[string]*ServerResolverBuilder)}
|
|
|
|
func init() {
|
|
resolver.Register(reg)
|
|
}
|
|
|
|
// Register a ServerResolverBuilder with the global registry.
|
|
func Register(res *ServerResolverBuilder) {
|
|
reg.lock.Lock()
|
|
defer reg.lock.Unlock()
|
|
reg.byAuthority[res.Authority()] = res
|
|
}
|
|
|
|
// Deregister the ServerResolverBuilder associated with the authority. Only used
|
|
// for testing.
|
|
func Deregister(authority string) {
|
|
reg.lock.Lock()
|
|
defer reg.lock.Unlock()
|
|
delete(reg.byAuthority, authority)
|
|
}
|