From e208d6980c1b3efa1827a3e12d2d1427fca597b8 Mon Sep 17 00:00:00 2001
From: ale <ale@incal.net>
Date: Sun, 28 Dec 2014 11:22:20 +0000
Subject: [PATCH] add versioning to the cluster runtime data in etcd
This change allows us to introduce changes to the inner workings of the
cluster that break backwards compatibility, allowing a smooth transition
to the new format.
---
api.go | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/api.go b/api.go
index 30fd0f1f..0d63f4c6 100644
--- a/api.go
+++ b/api.go
@@ -12,14 +12,26 @@ import (
"time"
)
-var (
- MasterElectionPath = "/icecast/cluster/master"
- MountPrefix = "/icecast/mounts/"
- NodePrefix = "/icecast/nodes/"
+const (
+ // Path to the mount configuration in etcd. This should never
+ // change, upgrades to the configuration format should be
+ // backwards-compatible.
+ MountPrefix = "/icecast/mounts/"
+
+ // Path for the cluster runtime data. Whenever the format of
+ // this data changes, the ABIVersion should be increased. A
+ // rolling restart of the cluster will then seamlessly cause a
+ // transition to the new consensus (the cluster will be
+ // partitioned in the meantime).
+ ABIVersion = "2"
+ MasterElectionPath = "/icecast/" + ABIVersion + "/cluster/master"
+ NodePrefix = "/icecast/" + ABIVersion + "/nodes/"
IcecastPort = 8000
IcecastMountPrefix = "/_stream"
+)
+var (
ErrIsDirectory = errors.New("key is a directory")
ErrIsFile = errors.New("key is a file")
)
--
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