Enable MVCC engine using command-line option

Tarantool 2.6 includes MVCC support [1]. When option `--mvcc`
is specified in a command-line options option
`memtx_use_mvcc_engine = true` passed to `box.cfg`
on Tarantool initialization.

1. tarantool/tarantool#4897

Closes #41

Author: ligurio

resources/tarantool/jepsen.lua

@@ -8,6 +8,7 @@ box.cfg {
     too_long_threshold = 0.5;
     custom_proc_title = 'jepsen';
     memtx_memory = 1024*1024*1024;
+    memtx_use_mvcc_engine = %TARANTOOL_MVCC%;
 }
 else
 box.cfg {
@@ -20,7 +21,8 @@ box.cfg {
     log_nonblock = false;
     too_long_threshold = 0.5;
     custom_proc_title = 'jepsen';
-    memtx_memory = 1024*1024*1024,
+    memtx_memory = 1024*1024*1024;
+    memtx_use_mvcc_engine = %TARANTOOL_MVCC%;
 }
 end
 

src/tarantool/db.clj

@@ -214,6 +214,7 @@
     (c/exec :echo (-> "tarantool/jepsen.lua" io/resource slurp
                       (str/replace #"%TARANTOOL_REPLICATION%" (replica-set test))
                       (str/replace #"%TARANTOOL_IS_READ_ONLY%" (boolean-to-str read-only))
+                      (str/replace #"%TARANTOOL_MVCC%" (boolean-to-str (:mvcc test)))
                       (str/replace #"%TARANTOOL_SINGLE_MODE%" (boolean-to-str (is-single-mode? test)))
                       (str/replace #"%TARANTOOL_DATA_ENGINE%" (:engine test)))
             :> "/etc/tarantool/instances.enabled/jepsen.lua")

src/tarantool/runner.clj

@@ -69,6 +69,9 @@
    [["-v" "--version VERSION"
      "What Tarantool version should we test?"
      :default "2.6"]
+    [nil "--mvcc"
+     "Enable MVCC engine"
+     :default false]
     ["-w" "--workload NAME" "Test workload to run"
      :parse-fn keyword
      :missing (str "--workload " (cli/one-of workloads))
@@ -131,6 +134,7 @@
             :os        ubuntu/os
             :db        (db/db (:version opts))
             :engine    (:engine opts)
+            :mvcc      (:mvcc opts)
             :pure-generators true
             :generator gen
             :checker   (checker/compose {:perf        (checker/perf)