blob: 31934a2a127a45edca25f8b1d066326ff2c8e24b [file] [log] [blame]
// Copyright 2017 The LUCI Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package policy
import (
"context"
"fmt"
"sync"
"time"
"github.com/golang/protobuf/proto"
"go.chromium.org/luci/common/logging"
"go.chromium.org/luci/config"
"go.chromium.org/luci/config/cfgclient"
)
// luciConfigFetcher implements ConfigFetcher interface via LUCI Config client.
//
// It fetches all config files at a single revision: the first config file
// is fetched at HEAD, and the rest of them are fetched at the same revision.
type luciConfigFetcher struct {
m sync.Mutex
rev string
}
func (f *luciConfigFetcher) Revision() string {
f.m.Lock()
defer f.m.Unlock()
return f.rev
}
func (f *luciConfigFetcher) FetchTextProto(c context.Context, path string, out proto.Message) error {
logging.Infof(c, "Reading %q", path)
c, cancel := context.WithTimeout(c, 40*time.Second) // URL fetch deadline
defer cancel()
var meta config.Meta
if err := cfgclient.Get(c, "services/${appid}", path, cfgclient.ProtoText(out), &meta); err != nil {
return err
}
f.m.Lock()
defer f.m.Unlock()
switch {
case f.rev == "":
f.rev = meta.Revision
case f.rev != meta.Revision:
// TODO(vadimsh): Lock all subsequent 'FetchTextProto' calls to the revision
// we fetched during the first call. Unfortunately cfgclient doesn't support
// fetching a specific revision. So we just fail if a wrong revision is
// fetched, assuming the state will "normalize" later.
return fmt.Errorf(
"expected config %q to be at rev %s, but got %s",
path, f.rev, meta.Revision)
}
return nil
}