set up proxies for cluster nodes that are themselves proxied via a remote

When there are multiple gateways to a cluster, this sets up proxying
for nodes that are accessed via a remote gateway.

Eg, when running in nyc and amsterdam is the remote gateway,
and it has node1 and node2, this sets up proxying for
amsterdam-node1 and amsterdam-node2. A client that has nyc as a remote
will see proxied remotes nyc-amsterdam-node1 and nyc-amsterdam-node2.

Command/UpdateCluster.hs

@@ -50,7 +50,7 @@ start = startingCustomOutput (ActionItemOther Nothing) $ do
 		let mynodes = S.map (ClusterNodeUUID . R.uuid) mynodesremotes
 		let recordednodes = fromMaybe mempty $ M.lookup cu $
 			clusterUUIDs recordedclusters
-		proxiednodes <- findProxiedNodes recordednodes 
+		proxiednodes <- findProxiedClusterNodes recordednodes 
 		let allnodes = S.union mynodes proxiednodes
 		if recordednodes == allnodes
 			then liftIO $ putStrLn $ safeOutput $
@@ -74,8 +74,8 @@ start = startingCustomOutput (ActionItemOther Nothing) $ do
 					"Removed node " ++ desc ++ " from cluster: " ++ clustername
 
 -- Finds nodes that are proxied by other cluster gateways.
-findProxiedNodes :: S.Set ClusterNodeUUID -> Annex (S.Set ClusterNodeUUID)
-findProxiedNodes recordednodes =
+findProxiedClusterNodes :: S.Set ClusterNodeUUID -> Annex (S.Set ClusterNodeUUID)
+findProxiedClusterNodes recordednodes =
 	(S.fromList . map asclusternode . filter isproxynode) <$> R.remoteList
   where
 	isproxynode r = 

Command/UpdateProxy.hs

@@ -10,11 +10,11 @@ module Command.UpdateProxy where
 import Command
 import qualified Annex
 import Logs.Proxy
+import Logs.Cluster
 import Annex.UUID
 import qualified Remote as R
 import qualified Types.Remote as R
 import Utility.SafeOutput
-import Types.Cluster
 
 import qualified Data.Map as M
 import qualified Data.Set as S
@@ -32,10 +32,8 @@ start = startingCustomOutput (ActionItemOther Nothing) $ do
 	rs <- R.remoteList
 	let remoteproxies = S.fromList $ map mkproxy $
 		filter (isproxy . R.gitconfig) rs
-	clusterproxies <-
-		(S.fromList . map mkclusterproxy . M.toList . annexClusters)
-		<$> Annex.getGitConfig
-	let proxies = remoteproxies <> clusterproxies
+	clusterproxies <- getClusterProxies
+	let proxies = S.union remoteproxies clusterproxies
 	u <- getUUID
 	oldproxies <- fromMaybe mempty . M.lookup u <$> getProxies
 	if oldproxies == proxies
@@ -60,5 +58,38 @@ start = startingCustomOutput (ActionItemOther Nothing) $ do
 	
 	mkproxy r = Proxy (R.uuid r) (R.name r)
 
+-- Automatically proxy nodes of any cluster this repository is configured
+-- to serve as a gateway for. Also proxy other cluster nodes that are
+-- themselves proxied via other remotes.
+getClusterProxies :: Annex (S.Set Proxy)
+getClusterProxies = do
+	mynodes <- (map mkclusterproxy . M.toList . annexClusters)
+		<$> Annex.getGitConfig
+	remoteproxiednodes <- findRemoteProxiedClusterNodes
+	let mynodesuuids = S.fromList $ map proxyRemoteUUID mynodes
+	-- filter out nodes we proxy for from the remote proxied nodes
+	-- to avoid cycles
+	let remoteproxiednodes' = filter
+		(\n -> proxyRemoteUUID n `S.notMember` mynodesuuids)
+		remoteproxiednodes
+	return (S.fromList (mynodes ++ remoteproxiednodes'))
+  where
 	mkclusterproxy (remotename, cu) = 
 		Proxy (fromClusterUUID cu) remotename
+
+findRemoteProxiedClusterNodes :: Annex [Proxy]
+findRemoteProxiedClusterNodes = do
+	myclusters <- (S.fromList . M.elems . annexClusters)
+		<$> Annex.getGitConfig
+	clusternodes <- clusterNodeUUIDs <$> getClusters
+	let isproxiedclusternode r
+		| remoteAnnexProxied (R.gitconfig r) =
+			case M.lookup (ClusterNodeUUID (R.uuid r)) clusternodes of
+				Nothing -> False
+				Just s -> not $ S.null $ 
+					S.intersection s myclusters
+		| otherwise = False
+	(map asproxy . filter isproxiedclusternode)
+		<$> R.remoteList
+  where
+	asproxy r = Proxy (R.uuid r) (R.name r)

doc/git-annex-extendcluster.mdwn

@@ -17,8 +17,8 @@ The `clustername` parameter is the name of the cluster.
 
 The next step after running this command is to configure
 any additional cluster nodes that this gateway serves to the cluster,
-then run [[git-annex-updatecluster]]. See the documentation of
-that command for details about configuring nodes.
+then run [[git-annex-updatecluster]] on each gateway. 
+See the documentation of that command for details about configuring nodes.
 
 # OPTIONS
 

doc/git-annex-updatecluster.mdwn

@@ -9,8 +9,8 @@ git-annex updatecluster
 # DESCRIPTION
 
 This command is used to record the nodes of a cluster in the git-annex
-branch. It should be run in the repository that will serve as a gateway
-to the cluster.
+branch, and set up proxying to the nodes. It should be run in the
+repository that will serve as a gateway to the cluster.
 
 It looks at the git config `remote.name.annex-cluster-node` of
 each remote. When that is set to the name of a cluster that has been