[couchdb] branch master updated: Add new /{db}/_sync_shards endpoint (admin-only) (#1811)

[wo...@apache.org]

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wohali pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/couchdb.git


The following commit(s) were added to refs/heads/master by this push:
     new 6cb0506  Add new /{db}/_sync_shards endpoint (admin-only) (#1811)
6cb0506 is described below

commit 6cb050610abde7a822d340b2652cba36b4f2b287
Author: Joan Touzet <wo...@users.noreply.github.com>
AuthorDate: Fri Jan 18 15:16:19 2019 -0500

    Add new /{db}/_sync_shards endpoint (admin-only) (#1811)
    
    This server admin-only endpoint forces an n-way sync of all shards
    across all nodes on which they are hosted.
    
    This can be useful for an administrator adding a new node to the
    cluster, after updating _dbs so that the new node hosts an existing db
    with content, to force the new node to sync all of that db's shards.
    
    Users may want to bump their `[mem3] sync_concurrency` value to a
    larger figure for the duration of the shards sync.
    
    Closes #1807
---
 src/chttpd/src/chttpd_auth_request.erl |  2 ++
 src/mem3/src/mem3_httpd.erl            | 20 +++++++++++++++++++-
 src/mem3/src/mem3_httpd_handlers.erl   |  1 +
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/chttpd/src/chttpd_auth_request.erl b/src/chttpd/src/chttpd_auth_request.erl
index 9110ed6..f85eb97 100644
--- a/src/chttpd/src/chttpd_auth_request.erl
+++ b/src/chttpd/src/chttpd_auth_request.erl
@@ -70,6 +70,8 @@ authorize_request_int(#httpd{path_parts=[_DbName, <<"_compact">>|_]}=Req) ->
     require_db_admin(Req);
 authorize_request_int(#httpd{path_parts=[_DbName, <<"_view_cleanup">>]}=Req) ->
     require_db_admin(Req);
+authorize_request_int(#httpd{path_parts=[_DbName, <<"_sync_shards">>]}=Req) ->
+    require_admin(Req);
 authorize_request_int(#httpd{path_parts=[_DbName|_]}=Req) ->
     db_authorization_check(Req).
 
diff --git a/src/mem3/src/mem3_httpd.erl b/src/mem3/src/mem3_httpd.erl
index 571f063..c922141 100644
--- a/src/mem3/src/mem3_httpd.erl
+++ b/src/mem3/src/mem3_httpd.erl
@@ -12,7 +12,8 @@
 
 -module(mem3_httpd).
 
--export([handle_membership_req/1, handle_shards_req/2]).
+-export([handle_membership_req/1, handle_shards_req/2,
+    handle_sync_req/2]).
 
 %% includes
 -include_lib("mem3/include/mem3.hrl").
@@ -52,6 +53,16 @@ handle_shards_req(#httpd{path_parts=[_DbName, <<"_shards">>]}=Req, _Db) ->
 handle_shards_req(#httpd{path_parts=[_DbName, <<"_shards">>, _DocId]}=Req, _Db) ->
     chttpd:send_method_not_allowed(Req, "GET").
 
+handle_sync_req(#httpd{method='POST',
+        path_parts=[_DbName, <<"_sync_shards">>]} = Req, Db) ->
+    DbName = mem3:dbname(couch_db:name(Db)),
+    ShardList = [S#shard.name || S <- mem3:ushards(DbName)],
+    [ sync_shard(S) || S <- ShardList ],
+    chttpd:send_json(Req, 202, {[{ok, true}]});
+handle_sync_req(Req, _) ->
+    chttpd:send_method_not_allowed(Req, "POST").
+
+
 %%
 %% internal
 %%
@@ -64,3 +75,10 @@ json_shards([#shard{node=Node, range=[B,E]} | Rest], AccIn) ->
     HexEnd = couch_util:to_hex(<<E:32/integer>>),
     Range = list_to_binary(HexBeg ++ "-" ++ HexEnd),
     json_shards(Rest, dict:append(Range, Node, AccIn)).
+
+sync_shard(ShardName) ->
+    Shards = mem3_shards:for_shard_name(ShardName),
+    [rpc:call(S1#shard.node, mem3_sync, push, [S1, S2#shard.node]) ||
+            S1 <- Shards, S2 <- Shards, S1 =/= S2],
+    ok.
+
diff --git a/src/mem3/src/mem3_httpd_handlers.erl b/src/mem3/src/mem3_httpd_handlers.erl
index d8e138c..7cbd9fe 100644
--- a/src/mem3/src/mem3_httpd_handlers.erl
+++ b/src/mem3/src/mem3_httpd_handlers.erl
@@ -18,6 +18,7 @@ url_handler(<<"_membership">>) -> fun mem3_httpd:handle_membership_req/1;
 url_handler(_) -> no_match.
 
 db_handler(<<"_shards">>) -> fun mem3_httpd:handle_shards_req/2;
+db_handler(<<"_sync_shards">>)   -> fun mem3_httpd:handle_sync_req/2;
 db_handler(_) -> no_match.
 
 design_handler(_) -> no_match.