[Tarantool-patches] [PATCH vshard 1/1] recovery: relax recovery messages verbosity

[Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Recovery fiber on the storages used to print messages about
starting recovery even when no recovery was needed yet:

    Starting ... buckets recovery step
    Finish bucket recovery step

It happened a lot during rebalancing even if it worked fine.
Because there appear receiving/sending buckets, and recovery
double-checks if they are really transferring, not stuck.

The patch makes recovery fiber not account the buckets, whose
transfer is actually in progress, as broken. Hence it won't print
the recovery messages anymore unless the transfer was really
interrupted.

Along with that the recovery now prints more details about the
first bucket which triggered the real recovery.

Closes #274
---
Branch: http://github.com/tarantool/vshard/tree/gerold103/gh-274-user-friendly-recovery
Issue: https://github.com/tarantool/vshard/issues/274

 vshard/storage/init.lua | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/vshard/storage/init.lua b/vshard/storage/init.lua
index 7045d91..8a019fa 100644
--- a/vshard/storage/init.lua
+++ b/vshard/storage/init.lua
@@ -736,21 +736,25 @@ local function recovery_step_by_type(type)
     local is_empty = true
     local recovered = 0
     local total = 0
+    local start_format = 'Starting %s buckets recovery step'
     for _, bucket in _bucket.index.status:pairs(type) do
         total = total + 1
         local bucket_id = bucket.id
         if M.rebalancer_transfering_buckets[bucket_id] then
             goto continue
         end
-        if is_empty then
-            log.info('Starting %s buckets recovery step', type)
-        end
-        is_empty = false
         assert(bucket_is_transfer_in_progress(bucket))
-        local destination = M.replicasets[bucket.destination]
+        local peer_uuid = bucket.destination
+        local destination = M.replicasets[peer_uuid]
         if not destination or not destination.master then
             -- No replicaset master for a bucket. Wait until it
             -- appears.
+            if is_empty then
+                log.info(start_format, type)
+                log.error('Can not find for bucket %s its peer %s', bucket_id,
+                          peer_uuid)
+                is_empty = false
+            end
             goto continue
         end
         local remote_bucket, err =
@@ -759,6 +763,15 @@ local function recovery_step_by_type(type)
         -- not be used to recovery anything. Try later.
         if not remote_bucket and (not err or err.type ~= 'ShardingError' or
                                   err.code ~= lerror.code.WRONG_BUCKET) then
+            if is_empty then
+                if err == nil then
+                    err = 'unknown'
+                end
+                log.info(start_format, type)
+                log.error('Error during recovery of bucket %s on replicaset '..
+                          '%s: %s', bucket_id, peer_uuid, err)
+                is_empty = false
+            end
             goto continue
         end
         -- Do nothing until the bucket on both sides stopped
@@ -772,13 +785,20 @@ local function recovery_step_by_type(type)
         if not bucket or not bucket_is_transfer_in_progress(bucket) then
             goto continue
         end
+        if is_empty then
+            log.info(start_format, type)
+        end
         if recovery_local_bucket_is_garbage(bucket, remote_bucket) then
             _bucket:update({bucket_id}, {{'=', 2, consts.BUCKET.GARBAGE}})
             recovered = recovered + 1
         elseif recovery_local_bucket_is_active(bucket, remote_bucket) then
             _bucket:replace({bucket_id, consts.BUCKET.ACTIVE})
             recovered = recovered + 1
+        elseif is_empty then
+            log.info('Bucket %s is %s local and %s on replicaset %s, waiting',
+                     bucket_id, bucket.status, remote_bucket.status, peer_uuid)
         end
+        is_empty = false
 ::continue::
     end
     if not is_empty then
-- 
2.24.3 (Apple Git-128)