Add ability to gracefully terminate existing changes feeds Calling fabric:end_changes() will cause all current changes feeds to gracefully exit without preventing new changes requests from starting (unlike maintenance_mode).
BugzID: 45762 This is a cherry-pick of: https://github.com/cloudant/fabric/commit/1b45cede8f11e209f28e3d06b9fda4cbdcd719cc Conflicts: src/fabric.erl src/fabric_view_changes.erl Project: http://git-wip-us.apache.org/repos/asf/couchdb-fabric/repo Commit: http://git-wip-us.apache.org/repos/asf/couchdb-fabric/commit/383f8f4d Tree: http://git-wip-us.apache.org/repos/asf/couchdb-fabric/tree/383f8f4d Diff: http://git-wip-us.apache.org/repos/asf/couchdb-fabric/diff/383f8f4d Branch: refs/heads/merge-diff-from-cloudant-fork Commit: 383f8f4dc46737fac646a6d90ff03b64c0d94109 Parents: d7d6be8 Author: Robert Newson <rnew...@apache.org> Authored: Sun Mar 29 13:38:38 2015 +0100 Committer: Mike Wallace <mikewall...@apache.org> Committed: Wed Jun 3 15:00:56 2015 +0100 ---------------------------------------------------------------------- src/fabric.erl | 6 +++++- src/fabric_view_changes.erl | 17 ++++++++++++++++- 2 files changed, 21 insertions(+), 2 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/couchdb-fabric/blob/383f8f4d/src/fabric.erl ---------------------------------------------------------------------- diff --git a/src/fabric.erl b/src/fabric.erl index 25205f8..26b9f62 100644 --- a/src/fabric.erl +++ b/src/fabric.erl @@ -29,7 +29,7 @@ % Views -export([all_docs/4, all_docs/5, changes/4, query_view/3, query_view/4, - query_view/6, get_view_group_info/2]). + query_view/6, get_view_group_info/2, end_changes/0]). % miscellany -export([design_docs/1, reset_validation_funs/1, cleanup_index_files/0, @@ -362,6 +362,10 @@ query_view(DbName, DDoc, ViewName, Callback, Acc0, QueryArgs0) -> get_view_group_info(DbName, DesignId) -> fabric_group_info:go(dbname(DbName), design_doc(DesignId)). +-spec end_changes() -> ok. +end_changes() -> + fabric_view_changes:increment_changes_epoch(). + %% @doc retrieve all the design docs from a database -spec design_docs(dbname()) -> {ok, [json_obj()]}. design_docs(DbName) -> http://git-wip-us.apache.org/repos/asf/couchdb-fabric/blob/383f8f4d/src/fabric_view_changes.erl ---------------------------------------------------------------------- diff --git a/src/fabric_view_changes.erl b/src/fabric_view_changes.erl index 92d08e7..7e6666c 100644 --- a/src/fabric_view_changes.erl +++ b/src/fabric_view_changes.erl @@ -13,6 +13,7 @@ -module(fabric_view_changes). -export([go/5, pack_seqs/1, unpack_seqs/2]). +-export([increment_changes_epoch/0]). %% exported for upgrade purposes. -export([keep_sending_changes/8]). @@ -37,6 +38,7 @@ go(DbName, Feed, Options, Callback, Acc0) when Feed == "continuous" orelse UpdateListener = {spawn_link(fabric_db_update_listener, go, [Parent, Ref, DbName, Timeout]), Ref}, + put(changes_epoch, get_changes_epoch()), try keep_sending_changes( DbName, @@ -86,8 +88,9 @@ keep_sending_changes(DbName, Args, Callback, Seqs, AccIn, Timeout, UpListen, T0) } = Collector, LastSeq = pack_seqs(NewSeqs), MaintenanceMode = config:get("couchdb", "maintenance_mode"), + NewEpoch = get_changes_epoch() > erlang:get(changes_epoch), if Limit > Limit2, Feed == "longpoll"; - MaintenanceMode == "true"; MaintenanceMode == "nolb" -> + MaintenanceMode == "true"; MaintenanceMode == "nolb"; NewEpoch -> Callback({stop, LastSeq, pending_count(Offset)}, AccOut); true -> WaitForUpdate = wait_db_updated(UpListen), @@ -459,6 +462,18 @@ validate_start_seq(DbName, Seq) -> {error, {bad_request, Reason}} end. +get_changes_epoch() -> + case application:get_env(fabric, changes_epoch) of + undefined -> + increment_changes_epoch(), + get_changes_epoch(); + {ok, Epoch} -> + Epoch + end. + +increment_changes_epoch() -> + application:set_env(fabric, changes_epoch, os:timestamp()). + unpack_seqs_test() -> meck:new(mem3), meck:new(fabric_view),
