forked from purpleidea/mgmt
/
strmap.go
115 lines (104 loc) · 4.52 KB
/
strmap.go
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// Mgmt
// Copyright (C) 2013-2017+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package etcd
import (
"fmt"
"strings"
"github.com/purpleidea/mgmt/util"
etcd "github.com/coreos/etcd/clientv3"
errwrap "github.com/pkg/errors"
)
// WatchStrMap returns a channel which spits out events on key activity.
// FIXME: It should close the channel when it's done, and spit out errors when
// something goes wrong.
func WatchStrMap(obj *EmbdEtcd, key string) chan error {
// new key structure is /$NS/strings/$key/$hostname = $data
path := fmt.Sprintf("/%s/strings/%s", NS, key)
ch := make(chan error, 1)
// FIXME: fix our API so that we get a close event on shutdown.
callback := func(re *RE) error {
// TODO: is this even needed? it used to happen on conn errors
//log.Printf("Etcd: Watch: Path: %v", path) // event
if re == nil || re.response.Canceled {
return fmt.Errorf("watch is empty") // will cause a CtxError+retry
}
if len(ch) == 0 { // send event only if one isn't pending
ch <- nil // event
}
return nil
}
_, _ = obj.AddWatcher(path, callback, true, false, etcd.WithPrefix()) // no need to check errors
return ch
}
// GetStrMap collects all of the strings which match a namespace in etcd.
func GetStrMap(obj *EmbdEtcd, hostnameFilter []string, key string) (map[string]string, error) {
// old key structure is /$NS/strings/$hostname/$key = $data
// new key structure is /$NS/strings/$key/$hostname = $data
// FIXME: if we have the $key as the last token (old key structure), we
// can allow the key to contain the slash char, otherwise we need to
// verify that one isn't present in the input string.
path := fmt.Sprintf("/%s/strings/%s", NS, key)
keyMap, err := obj.Get(path, etcd.WithPrefix(), etcd.WithSort(etcd.SortByKey, etcd.SortAscend))
if err != nil {
return nil, errwrap.Wrapf(err, "could not get strings in: %s", key)
}
result := make(map[string]string)
for key, val := range keyMap {
if !strings.HasPrefix(key, path) { // sanity check
continue
}
str := strings.Split(key[len(path):], "/")
if len(str) != 2 {
return nil, fmt.Errorf("unexpected chunk count of %d", len(str))
}
_, hostname := str[0], str[1]
if hostname == "" {
return nil, fmt.Errorf("unexpected chunk length of %d", len(hostname))
}
// FIXME: ideally this would be a server side filter instead!
if len(hostnameFilter) > 0 && !util.StrInList(hostname, hostnameFilter) {
continue
}
//log.Printf("Etcd: GetStr(%s): (Hostname, Data): (%s, %s)", key, hostname, val)
result[hostname] = val
}
return result, nil
}
// SetStrMap sets a key and hostname pair to a certain value. If the value is
// nil, then it deletes the key. Otherwise the value should point to a string.
// TODO: TTL or delete disconnect?
func SetStrMap(obj *EmbdEtcd, hostname, key string, data *string) error {
// key structure is /$NS/strings/$key/$hostname = $data
path := fmt.Sprintf("/%s/strings/%s/%s", NS, key, hostname)
ifs := []etcd.Cmp{} // list matching the desired state
ops := []etcd.Op{} // list of ops in this transaction (then)
els := []etcd.Op{} // list of ops in this transaction (else)
if data == nil { // perform a delete
// TODO: use https://github.com/coreos/etcd/pull/7417 if merged
//ifs = append(ifs, etcd.KeyExists(path))
ifs = append(ifs, etcd.Compare(etcd.Version(path), ">", 0))
ops = append(ops, etcd.OpDelete(path))
} else {
data := *data // get the real value
ifs = append(ifs, etcd.Compare(etcd.Value(path), "=", data)) // desired state
els = append(els, etcd.OpPut(path, data))
}
// it's important to do this in one transaction, and atomically, because
// this way, we only generate one watch event, and only when it's needed
_, err := obj.Txn(ifs, ops, els) // TODO: do we need to look at response?
return errwrap.Wrapf(err, "could not set strings in: %s", key)
}