[GitHub] iilyak commented on a change in pull request #470: Scheduling Replicator

[gi...@git.apache.org]

iilyak commented on a change in pull request #470: Scheduling Replicator
URL: https://github.com/apache/couchdb/pull/470#discussion_r110995368
 
 

 ##########
 File path: src/couch_replicator/src/couch_replicator_scheduler.erl
 ##########
 @@ -0,0 +1,1380 @@
+% Licensed under the Apache License, Version 2.0 (the "License"); you may not
+% use this file except in compliance with the License. You may obtain a copy of
+% the License at
+%
+%   http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+% License for the specific language governing permissions and limitations under
+% the License.
+
+-module(couch_replicator_scheduler).
+-behaviour(gen_server).
+-behaviour(config_listener).
+-vsn(1).
+
+-include("couch_replicator_scheduler.hrl").
+-include("couch_replicator.hrl").
+-include("couch_replicator_api_wrap.hrl").
+-include_lib("couch/include/couch_db.hrl").
+
+%% public api
+-export([start_link/0, add_job/1, remove_job/1, reschedule/0]).
+-export([rep_state/1, find_jobs_by_dbname/1, find_jobs_by_doc/2]).
+-export([job_summary/2, health_threshold/0]).
+-export([jobs/0, job/1]).
+
+%% gen_server callbacks
+-export([init/1, terminate/2, code_change/3]).
+-export([handle_call/3, handle_cast/2, handle_info/2]).
+-export([format_status/2]).
+
+%% config_listener callback
+-export([handle_config_change/5, handle_config_terminate/3]).
+
+%% types
+-type event_type() :: added | started | stopped | {crashed, any()}.
+-type event() :: {Type:: event_type(), When :: erlang:timestamp()}.
+-type history() :: nonempty_list(event()).
+
+%% definitions
+-define(MAX_BACKOFF_EXPONENT, 10).
+-define(BACKOFF_INTERVAL_MICROS, 30 * 1000 * 1000).
+-define(DEFAULT_HEALTH_THRESHOLD_SEC, 2 * 60).
+-define(RELISTEN_DELAY, 5000).
+
+-define(DEFAULT_MAX_JOBS, 500).
+-define(DEFAULT_MAX_CHURN, 20).
+-define(DEFAULT_MAX_HISTORY, 20).
+-define(DEFAULT_SCHEDULER_INTERVAL, 60000).
+-record(state, {interval, timer, max_jobs, max_churn, max_history}).
+-record(job, {
+          id :: job_id() | '$1' | '_',
+          rep :: #rep{} | '_',
+          pid :: undefined | pid() | '$1' | '_',
+          monitor :: undefined | reference() | '_',
+          history :: history() | '_'}).
+
+-record(stats_acc, {
+          now  :: erlang:timestamp(),
+          pending_t = 0 :: non_neg_integer(),
+          running_t = 0 :: non_neg_integer(),
+          crashed_t = 0 :: non_neg_integer(),
+          pending_n = 0 :: non_neg_integer(),
+          running_n = 0 :: non_neg_integer(),
+          crashed_n = 0 :: non_neg_integer()}).
+
+
+%% public functions
+
+-spec start_link() -> {ok, pid()} | ignore | {error, term()}.
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+
+-spec add_job(#rep{}) -> ok.
+add_job(#rep{} = Rep) when Rep#rep.id /= undefined ->
+    Job = #job{
+        id = Rep#rep.id,
+        rep = Rep,
+        history = [{added, os:timestamp()}]},
+    gen_server:call(?MODULE, {add_job, Job}, infinity).
+
+
+-spec remove_job(job_id()) -> ok.
+remove_job(Id) ->
+    gen_server:call(?MODULE, {remove_job, Id}, infinity).
+
+
+-spec reschedule() -> ok.
+% Trigger a manual reschedule. Used for testing and/or ops.
+reschedule() ->
+    gen_server:call(?MODULE, reschedule, infinity).
+
+
+-spec rep_state(rep_id()) -> #rep{} | nil.
+rep_state(RepId) ->
+    case (catch ets:lookup_element(?MODULE, RepId, #job.rep)) of
+        {'EXIT',{badarg, _}} ->
+            nil;
+        Rep ->
+            Rep
+    end.
+
+
+-spec job_summary(job_id(), non_neg_integer()) -> [_] | nil.
+job_summary(JobId, HealthThreshold) ->
 
 Review comment:
   What is the context in which this function is called? In my understanding it is a public API function therefore it could be called from anywhere at any time. Since `job_by_id` doesn't use `catch` the call to job_summary can fail with `badarg` if `ets` table doesn't exists. Which violates the spec.
 
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services