Mas d31 i413 (#415)

* Allow snapshots to be reused in queries

Allow for a full bookie snapshot to be re-used for multiple queries, not just KV fetches.

* Reduce log noise

The internal dummy tag is expected so should not prompt a log on reload

* Snapshot should have same status of active db

wrt head_only and head_lookup

* Allow logging to specified on snapshots

* Shutdown snapshot bookie is primary goes down

Inker and Penciller already will shut down based on `erlang:monitor/2`

* Review feedback

Formatting and code readability fixes

src/leveled_penciller.erl

@@ -628,16 +628,16 @@ init([LogOpts, PCLopts]) ->
             %% exits
 	        BookieMonitor = 
                 erlang:monitor(process, PCLopts#penciller_options.bookies_pid),
-
-            {ok, State} = pcl_registersnapshot(SrcPenciller, 
-                                                self(), 
-                                                Query, 
-                                                BookiesMem, 
-                                                LongRunning),
+            {ok, State} =
+                pcl_registersnapshot(
+                    SrcPenciller, self(), Query, BookiesMem, LongRunning),
             leveled_log:log(p0001, [self()]),
-            {ok, State#state{is_snapshot = true,
-			     bookie_monref = BookieMonitor,
-			     source_penciller = SrcPenciller}};
+            {ok,
+                State#state{
+                    is_snapshot = true,
+                    clerk = undefined,
+                    bookie_monref = BookieMonitor,
+                    source_penciller = SrcPenciller}};
         {_RootPath, _Snapshot=false, _Q, _BM} ->
             start_from_file(PCLopts)
     end.    
@@ -1131,22 +1131,21 @@ handle_cast({fetch_levelzero, Slot, ReturnFun}, State) ->
     ReturnFun(lists:nth(Slot, State#state.levelzero_cache)),
     {noreply, State};
 handle_cast({log_level, LogLevel}, State) ->
-    PC = State#state.clerk,
-    ok = leveled_pclerk:clerk_loglevel(PC, LogLevel),
-    ok = leveled_log:set_loglevel(LogLevel),
+    update_clerk(
+        State#state.clerk, fun leveled_pclerk:clerk_loglevel/2, LogLevel),
     SSTopts = State#state.sst_options,
     SSTopts0 = SSTopts#sst_options{log_options = leveled_log:get_opts()},
     {noreply, State#state{sst_options = SSTopts0}};
 handle_cast({add_logs, ForcedLogs}, State) ->
-    PC = State#state.clerk,
-    ok = leveled_pclerk:clerk_addlogs(PC, ForcedLogs),
+    update_clerk(
+        State#state.clerk, fun leveled_pclerk:clerk_addlogs/2, ForcedLogs),
     ok = leveled_log:add_forcedlogs(ForcedLogs),
     SSTopts = State#state.sst_options,
     SSTopts0 = SSTopts#sst_options{log_options = leveled_log:get_opts()},
     {noreply, State#state{sst_options = SSTopts0}};
 handle_cast({remove_logs, ForcedLogs}, State) ->
-    PC = State#state.clerk,
-    ok = leveled_pclerk:clerk_removelogs(PC, ForcedLogs),
+    update_clerk(
+        State#state.clerk, fun leveled_pclerk:clerk_removelogs/2, ForcedLogs),
     ok = leveled_log:remove_forcedlogs(ForcedLogs),
     SSTopts = State#state.sst_options,
     SSTopts0 = SSTopts#sst_options{log_options = leveled_log:get_opts()},
@@ -1224,6 +1223,12 @@ sst_filename(ManSQN, Level, Count) ->
 %%% Internal functions
 %%%============================================================================
 
+-spec update_clerk(pid()|undefined, fun((pid(), term()) -> ok), term()) -> ok.
+update_clerk(undefined, _F, _T) ->
+    ok;
+update_clerk(Clerk, F, T) when is_pid(Clerk) ->
+    F(Clerk, T).
+
 -spec start_from_file(penciller_options()) -> {ok, pcl_state()}.
 %% @doc
 %% Normal start of a penciller (i.e. not a snapshot), needs to read the