From d70a02e7415caccd13fad8dda417d0d18a112a83 Mon Sep 17 00:00:00 2001
From: Anders Svensson
Date: Sun, 24 Feb 2013 17:39:46 +0100
Subject: More flexible distribution config
Allow both share_peers and use_shared_peers to be a list of nodes, or a
function that returns a list of nodes.
---
lib/diameter/doc/src/diameter.xml | 75 ++++++++++++++++++++++++-----------
lib/diameter/doc/src/diameter_app.xml | 8 ++--
2 files changed, 56 insertions(+), 27 deletions(-)
(limited to 'lib/diameter/doc/src')
diff --git a/lib/diameter/doc/src/diameter.xml b/lib/diameter/doc/src/diameter.xml
index df9e03b2da..8ad4af85a3 100644
--- a/lib/diameter/doc/src/diameter.xml
+++ b/lib/diameter/doc/src/diameter.xml
@@ -43,7 +43,7 @@ under the License.
-%VSN%
+
diameter.xml
@@ -774,8 +774,8 @@ Application-Id AVP's in particular.
| evaluable()}
-
-Specifies the degree to which multiple transport connections to the
-same peer are accepted by the service.
+Specifies the degree to which the service allows multiple transport
+connections to the same peer.
If type [node()] then a connection is rejected if another already
@@ -831,40 +831,60 @@ outgoing requests.
-{share_peers, boolean()}
+{share_peers, boolean() | [node()] | evaluable()}
-
-Specifies whether or not peer connections on the local Erlang node
-are shared with services on visible nodes (as returned by &nodes;).
-Peers shared from remote nodes become available in the candidates list
-passed as the second argument to &app_pick_peer; callbacks.
+Specifies nodes to which peer connections established on the local
+Erlang node are communicated.
+Shared peers become available in the remote candidates list passed to
+&app_pick_peer; callbacks on remote nodes whose services are
+configured to use them: see use_shared_peers below.
-Defaults to false.
+If false then peers are not shared.
+If [node()] then peers are shared with the specified list of
+nodes.
+If evaluable() then peers are shared with the nodes returned
+by the specified function, evaluated whenever a peer connection
+becomes available or a remote service requests information about local
+connections.
+The value true is equivalent to fun &nodes;.
+The value node() in a node list is ignored, so a collection of
+services can all be configured to share with the same list of
+nodes.
-
-Peers are only shared with other services of the same name.
-Since the value of the &application_opt; alias is the handle
-for identifying a peer, both local and remote, as a candidate for an
-outgoing request, services that share peers should use the same
-aliases for identifying their supported applications.
-
+Defaults to false.
-Services that share peers can do so in order to distribute the
-implementation of a Diameter node across multiple Erlang nodes, in
-which case the participating services should typically be configured
-with identical &capabilities;.
+Peers are only shared with services of the same name for the purpose
+of sending outgoing requests.
+Since the value of the &application_opt; alias, passed to
+&call;, is the handle for identifying a peer as a suitable
+candidate, services that share peers must use the same aliases to
+identify their supported applications.
+They should typically also configure identical &capabilities;, since
+by sharing peer connections they are distributing the implementation
+of a single Diameter node across multiple Erlang nodes.
-{use_shared_peers, boolean()}
+{use_shared_peers, boolean() | [node()] | evaluable()}
-
-Specifies whether or not the service makes use of peer connections
-shared by identically named services on other Erlang nodes.
+Specifies nodes from which communicated peers are made available in
+the remote candidates list of &app_pick_peer; callbacks.
+
+
+If false then remote peers are not used.
+If [node()] then only peers from the specified list of nodes
+are used.
+If evaluable() then only peers returned by the specified
+function are used, evaluated whenever a remote service communicates
+information about an available peer connection.
+The value true is equivalent to fun &nodes;.
+The value node() in a node list is ignored.
Defaults to false.
@@ -874,6 +894,15 @@ Defaults to false.
A service that does not use shared peers will always pass the empty
list as the second argument of &app_pick_peer; callbacks.
+
+
+
+Sending a request over a peer connection on a remote node is less
+efficient than sending it over a local connection.
+It may be preferable to make use of the &service_opt;
+restrict_connections and maintain a dedicated connection on
+each node from which requests are sent.
+
diff --git a/lib/diameter/doc/src/diameter_app.xml b/lib/diameter/doc/src/diameter_app.xml
index d094e1bade..d4fb792787 100644
--- a/lib/diameter/doc/src/diameter_app.xml
+++ b/lib/diameter/doc/src/diameter_app.xml
@@ -37,7 +37,7 @@ under the License.
-%REV%
+
diameter_app.xml
@@ -297,9 +297,9 @@ The return values false and {false, State} (that is,
-RemoteCandidates is the empty list if the service has been
-configured with the (default) &mod_service_opt;
-{use_shared_peers, false}.
+The &mod_service_opt; use_shared_peers determines whether or
+not a service uses peers shared from other nodes.
+If not then RemoteCandidates is the empty list.
--
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