88516546fa
The old system with vendor/ and git submodules worked great, unfortunately FUD around git submodules seemed to scare people away and golang moved to a go.mod system that adds a new lock file format instead of using the built-in git version. It's now almost impossible to use modern golang without this, so we've switched. So much for the golang compatibility promise-- turns out it doesn't apply to the useful parts that I actually care about like this. Thanks to frebib for his incredibly valuable contributions to this patch. This snide commit message is mine alone. This patch also mixes in some changes due to legacy golang as we've also bumped the minimum version to 1.16 in the docs and tests. Lastly, we had to disable some tests and fix up a few other misc things to get this passing. We've definitely hot bugs in the go.mod system, and our Makefile tries to workaround those.
98 lines
3.7 KiB
Go
98 lines
3.7 KiB
Go
// Mgmt
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// Copyright (C) 2013-2021+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package str
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import (
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"context"
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"fmt"
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"github.com/purpleidea/mgmt/etcd/interfaces"
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"github.com/purpleidea/mgmt/util/errwrap"
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etcd "go.etcd.io/etcd/client/v3"
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etcdutil "go.etcd.io/etcd/client/v3/clientv3util"
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)
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const (
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ns = "" // in case we want to add one back in
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)
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// WatchStr returns a channel which spits out events on key activity.
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// FIXME: It should close the channel when it's done, and spit out errors when
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// something goes wrong.
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// XXX: since the caller of this (via the World API) has no way to tell it it's
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// done, does that mean we leak go-routines since it might still be running, but
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// perhaps even blocked??? Could this cause a dead-lock? Should we instead
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// return some sort of struct which has a close method with it to ask for a
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// shutdown?
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func WatchStr(ctx context.Context, client interfaces.Client, key string) (chan error, error) {
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// new key structure is $NS/strings/$key = $data
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path := fmt.Sprintf("%s/strings/%s", ns, key)
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return client.Watcher(ctx, path)
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}
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// GetStr collects the string which matches a global namespace in etcd.
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func GetStr(ctx context.Context, client interfaces.Client, key string) (string, error) {
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// new key structure is $NS/strings/$key = $data
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path := fmt.Sprintf("%s/strings/%s", ns, key)
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keyMap, err := client.Get(ctx, path, etcd.WithPrefix())
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if err != nil {
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return "", errwrap.Wrapf(err, "could not get strings in: %s", key)
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}
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if len(keyMap) == 0 {
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return "", interfaces.ErrNotExist
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}
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if count := len(keyMap); count != 1 {
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return "", fmt.Errorf("returned %d entries", count)
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}
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val, exists := keyMap[path]
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if !exists {
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return "", fmt.Errorf("path `%s` is missing", path)
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}
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return val, nil
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}
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// SetStr sets a key and hostname pair to a certain value. If the value is nil,
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// then it deletes the key. Otherwise the value should point to a string.
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// TODO: TTL or delete disconnect?
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func SetStr(ctx context.Context, client interfaces.Client, key string, data *string) error {
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// key structure is $NS/strings/$key = $data
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path := fmt.Sprintf("%s/strings/%s", ns, key)
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ifs := []etcd.Cmp{} // list matching the desired state
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ops := []etcd.Op{} // list of ops in this transaction (then)
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els := []etcd.Op{} // list of ops in this transaction (else)
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if data == nil { // perform a delete
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ifs = append(ifs, etcdutil.KeyExists(path))
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//ifs = append(ifs, etcd.Compare(etcd.Version(path), ">", 0))
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ops = append(ops, etcd.OpDelete(path))
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} else {
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data := *data // get the real value
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ifs = append(ifs, etcd.Compare(etcd.Value(path), "=", data)) // desired state
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els = append(els, etcd.OpPut(path, data))
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}
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// it's important to do this in one transaction, and atomically, because
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// this way, we only generate one watch event, and only when it's needed
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_, err := client.Txn(ctx, ifs, ops, els) // TODO: do we need to look at response?
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return errwrap.Wrapf(err, "could not set strings in: %s", key)
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}
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