From 2f885a790668681e123576e93a1de3be31b5bded Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Fri, 28 Aug 2015 14:18:17 +0100
Subject: [PATCH] Reclaim all addresses on restart

---
 ipam/claim.go    |  4 ++++
 site/features.md | 15 ++++++++++++---
 weave            |  4 ++++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/ipam/claim.go b/ipam/claim.go
index 20ec6519..0173af6a 100644
--- a/ipam/claim.go
+++ b/ipam/claim.go
@@ -40,6 +40,9 @@ func (c *claim) Try(alloc *Allocator) bool {
 
 	alloc.establishRing()
 
+	// If we had heard that this container died, resurrect it
+	delete(alloc.dead, c.ident) // (delete is no-op if key not in map)
+
 	switch owner := alloc.ring.Owner(c.addr); owner {
 	case alloc.ourName:
 		// success
@@ -78,6 +81,7 @@ func (c *claim) Try(alloc *Allocator) bool {
 		}
 	case c.ident:
 		// same identifier is claiming same address; that's OK
+		alloc.debugln("Re-Claimed", c.addr, "for", c.ident)
 		c.sendResult(nil)
 	default:
 		// Addr already owned by container on this machine
diff --git a/site/features.md b/site/features.md
index 02a8b2a4..3612a151 100644
--- a/site/features.md
+++ b/site/features.md
@@ -167,12 +167,21 @@ the weave network:
     host1$ weave ps a1
     a1 16:c0:6f:5d:c5:73 10.32.0.3/12
 
-There is also a `weave restart` command, if you are not using the
-weave Docker API proxy:
+It works the same if you stop and immediately restart:
+
+    host1$ docker stop a1
+    host1$ docker start a1
+
+However, additional addresses added with the `weave attach` command
+will not be retained.
+
+There is also a `weave restart` command, which does re-attach all
+current IP addresses:
 
     host1$ weave restart b1
 
-(note that the IP address is held for a limited time - currently five seconds)
+(note that the IP addresses are held for a limited time - currently
+five seconds)
 
 ### <a name="naming-and-discovery"></a>Naming and discovery
 
diff --git a/weave b/weave
index 65172f01..8128bd44 100755
--- a/weave
+++ b/weave
@@ -2036,6 +2036,10 @@ EOF
         create_bridge
         ALL_CIDRS=$(with_container_addresses echo_cidrs $1)
         RES=$(docker restart "$1")
+        CONTAINER=$(container_id $1)
+        for CIDR in $ALL_CIDRS ; do
+            call_weave PUT /ip/$CONTAINER/${CIDR%/*}
+        done
         with_container_netns_or_die $1 attach $ALL_CIDRS
         when_weave_running with_container_fqdn $1 put_dns_fqdn $ALL_CIDRS
         echo $RES