A container node is expected to have full "get" access to assemble the
object.
A non-container node is expected to forward any request to a container node.
Any token is expected to be issued for an original request sender not for a
node so any new request is invalid by design with that token.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Do not lose meta information of the original requests: cache session and
bearer tokens of the original request b/w a new generated ones. Middle
request wrappers should not contain any meta information, since it is
useless (e.g. ACL service checks only the original tokens).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
After presenting request statuses on the API level, all the errors are
unwrapped before sending to the caller side. It led to a losing invalid
request's context.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
It was needed before we started to flush during transition to
`degraded` mode. Now it is confusing.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Do not use node's local storage if it is clear that an object will be
removed anyway as a redundant. It requires moving the changing local storage
logic from the validation step to the local target implementation.
It allows performing any relations checks (e.g. object locking) only if a
node is considered as a valid container member and is expected to store
(stored previously) all the helper objects (e.g. `LOCK`, `TOMBSTONE`, etc).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
It is not an error: removing virtual object is expected and should be just
skipped. Getting a virtual object with `raw` flag is considered as an
impossible action, all the virtual objects removals will be handled via
their children's removals implicitly.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Currently there is a possibility for modifying operations to fail
because of I/O errors and a new tree to be created on another shard.
This commit adds existence check for modifying operations.
Read operations remain as they are, not to slow things.
`TreeDrop` is an exception, because this is a tree removal and trying
multiple shards is not an unwanted behaviour.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
By default writecache puts the whole object to update storage ID.
This logic comes from the times when we needed to put objects
in the metabase by the writecache itself. Now this is done by the
blobstor at unmarshaling objects during flush only to update storage ID
is an overkill.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
All logic errors are wrapped in `logicerr.Logical` type and do not
affect shard error counter.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
In previous implementation `Shard.Delete` logged writecache's removal
failures in `error` level. There is a need to decrease severity of these
log records since they aren't critical and don't require individual
review.
Change level of the message to `info`.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
From the `Bucket.ForEach` doc:
```
The provided function must not modify the bucket; this will result in undefined behavior.
```
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
After the refactor there are new storage characteristics: a type and
a general storage id (that could be stringified).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
In previous implementation turning to maintenance mode using NeoFS CLI
required NeoFS API endpoint. This was not convenient from the user
perspective. It's worth to move networks settings' check to the server
side.
Add `force_maintenance` field to `SetNetmapStatusRequest.Body` message
of Control API. Add `force` flag to `neofs-cli control set-status`
command which sets corresponding field in the requests body if status is
`maintenance`. Force flag is ignored for any other status.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Iterate over every shard and search for the container's trees. Final result
is a concatenation of shards' results. It is considered that one fixed tree
is placed on one fixed shard but the different trees of a fixed container
could be placed on different shards.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Add `SynchronizeAllTrees` method of the Tree service. It allows fetching
tree IDs and sync all of them. Share common logic b/w the new method and
the `SynchronizeTree`.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Add the node position in a container and the container size to the CID
descriptor that is passed to the `TreeApply`. Previously, `checkValid` does
not allow any log operarations.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
In the 2nd version, there was a database format change: buckets have changed
their keys, so it becomes impossible to check the version in the 1 -> 2+
migrations because of different buckets that store info about the version.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Storage node should not provide NeoFS Object API service when it is
under maintenance.
Declare `Common` service that unifies behavior of all object operations.
The implementation pre-checks if node is under maintenance and returns
`apistatus.NodeUnderMaintenance` if so. Use `Common` service as a first
logical processor in object service pipeline.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
In some scenarios original session can be unrelated to the objects which
are read internally by the node. For example, node requests child
objects when removing the parent one.
Tune internal NeoFS API client used by node's Object API server to
ignore unrelated sessions in `GetObject` / `HeadObject` / `PayloadRange`
ops.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
If shard ID is stored in metabase (it is not the first time boot), read it,
set it, use it (not a generated one) in the metrics writer.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Make it store its internal `zap.Logger`'s level. Also, make all the
components to accept internal `logger.Logger` instead of `zap.Logger`; it
will simplify future refactor.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Current spec allows denying GET_RANGE requests from other storage nodes.
However, GET should always be allowed and it is enough to perform
GET_RANGE locally
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
In previous implementation `ObjectService.Get` RPC handler failed with
`parent address in child object differs` while assembling the "big"
object. This was caused by the child check which required parent
reference to be set in all child objects. The check was impracticable
because not all elements of the split-chain have a link to the parent.
Make `execCtx.isChild` to return `true` if parameterized object has no
parent header in its own header.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Node response with `NODE_UNDER_MAINTENANCE` status signals that the node
was switched to maintenance mode. There is a delay between the actual
switch and the reflection in the network map of up to one epoch. To
speed up the reaction to the maintenance, it is required to recognize
such node responses in the Policer.
Make `Policer.processNodes` to exclude elements with shortage decreasing
on `NODE_UNDER_MAINTENANCE` status response.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Nodes under maintenance SHOULD not respond to object requests. Based on
this, storage node's Policer SHOULD consider such nodes as problem ones.
However, to prevent spam with the new replicas, on the contrary, Policer
should consider them normal.
Make `Policer.processNodes` to exclude elements if `IsMaintenance()`
with shortage decreasing.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Make `replicator.TaskResult` to accept `netmap.NodeInfo` type instead of
uint64 in order to clarify the meaning and prevent passing the random
numbers.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
It doesn't make sense to check object relation in session check of
`ObjectService.Put` RPC which has been spawned by `ObjectService.Delete`
with session. Session issuer can't predict identifier of the tombstone
object to be created.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Currently, when removing shard special care must be taken with respect
to shard numbering. `mode: disabled` allows to leave shard configuration
in place while also ignoring it during initialization. This makes
disk replacement much more convenient.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
In previous implementation of `neofs-node` app object session was not
checked for substitution of the object related to it. Also, for access
checks, the session object was substituted instead of the one from the
request. This, on the one hand, made it possible to inherit the session
from the parent object for authorization for certain actions. On the
other hand, it covered the mentioned object substitution, which is a
critical vulnerability.
Next changes are applied to processing of all Object service requests:
- check if object session relates to the requested object
- use requested object in access checks.
Disclosed problem of object context inheritance will be solved within
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
In previous implementation node blocked any operation of local object
storage in maintenance mode. There is a need to perform some storage
operations like data evacuation or restoration.
Do not call block storage engine in maintenance mode. Make all Object
service operations to return `apistatus.NodeUnderMaintenance` error from
each local op.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
After recent Netmap contract changes all read methods which return
network map (either candidates or snapshots) encode node descriptors
into same structure.
Decode `netmap.Node` contract-side structure from the call results.
Replace node state with the value from the `netmap.Node.State` field.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
Storage node can be requested to be switched into `MAINTENANCE` state.
Inner Ring should accept such requests only if network configuration
allows it.
Make `Processor` of Netmap contract's notifications to depend on
`state.NetworkSettings`. Make `Processor.processUpdatePeer` to call
`MaintenanceModeAllowed` if notification event relates to `MAINTENANCE`
mode`. Share singe `state.NetworkSettings` provider in Inner Ring
application.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
After recent changes Netmap contract can send `UpdateState` notification
event with `MAINTENANCE` node's state. There is a need to provide
functionality to work with the status.
Provide `UpdatePeer.Maintenance` method. Support new state in
`ParseUpdatePeer` and `ParseUpdatePeerNotary` functions.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
After recent changes in NeoFS protocol storage nodes can be in
`MAINTENANCE` state. There is a need to support this state in
`UpdateState` operation.
Add `UpdatePeerPrm.SetMaintenance` method which makes node to be
switched into `MAINTENANCE` mode after the `UpdatePeerState` operation.
New functionality is going to be used in Storage node application for
Control API serving.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Inner Ring should allow registering of storage nodes with `MAINTENANCE`
state in the NeoFS network only if its configuration allows this status.
Make `networkSettings.MaintenanceModeAllowed` to call
`MaintenanceModeAllowed` method of underlying Netmap contract's client
in order to assert state allowance.
From now nodes will be accepted to the network with `MAINTENANCE` state
only with the appropriate network configuration.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
After recent changes in the NeoFS API protocol network configuration
contains `MaintenanceModeAllowed` boolean flag. There is a need to
support the config value in all NeoFS applications.
Provide `Client.MaintenanceModeAllowed` method which read the config
from the Sidechain. Extend `NetworkConfiguration` structure with
`MaintenanceModeAllowed` field.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`NetworkConfiguration` represents NeoFS network configuration stored in
the Sidechain. In previous implementation the configuration missed flag
of disabled homomorphic hashing.
Add `NetworkConfiguration.HomomorphicHashingDisabled` boolean field.
Decode the field in `Client.ReadNetworkConfiguration` method. Print this
value in `netmap netinfo` command of NeoFS CLI.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
`readBoolConfig` method is going to be reused for reading other
configuration values. All boolean settings are `false` by default, so it
makes sense to return default value on missing key directly from
`readBoolConfig`.
Handle `ErrConfigNotFound` case in `readBoolConfig` method. Change
`HomomorphicHashDisabled` method to call `readBoolConfig` directly.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
There is a need to prevent limitless abuse of MAINTENANCE status of the
storage nodes. To do this, configuration of the NeoFS network is going
to be extended with the flag which allows the state. Until this is done,
it makes sense to prepare a site for this in the code.
Define `state.NetworkSettings` interface as an abstraction of global
network configuration within the `state` package. Make
`NetMapCandidateValidator` to depend on `NetworkSettings` and provide
corresponding field setter. Change `VerifyAndUpdate` method's behavior
to return an error for candidates with MAINTENANCE state if this state
is disallowed by the network configuration. Provide `NetworkSettings`
from the wrapper over Netmap contract's client on Inner Ring application
side. The provider is implemented to statically disallow MAINTENANCE
mode in order to save previous behavior.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
New network status of storage nodes is going to be introduced. To
simplify the addition, it would be useful to prepare the code for this.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation Inner Ring allowed storage nodes with any
state to register in the network. According to the current design, only
nodes with ONLINE state are allowed to enter the network map.
Create new `state` sub-package of `nodevalidation` package of Inner Ring
application. Define `state.NetMapCandidateValidator` type and provide
`NodeValidator` interface required by the Inner Ring's processor of
`Netmap` contract's notification events. Embed new validator into the
one used by the Inner Ring application.
From now all `AddPeer` notifications with node state other than `ONLINE`
will be denied.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Degraded mode allows us to operate without an SSD,
thus writecache should be unavailable in this mode.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Add a common error for this case because it is not an error
which should increase error counter. Single error simplifies checks on
the call-site.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Negative values have no sense. On the other hand it differs from the
blobovnicza's configuration and prevents unification.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Allow user to initiate flushing objects from a writecache.
We need this in 2 cases:
1. During writecache storage schema update, it should be flushed with
the old version of node and started clean with a new one.
2. During SSD replacement, to avoid data loss.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Replace `ProcessCurrentNetMap` method of `NodeState` interface with
`ReadCurrentNetMap` one with two changes:
* Replace network map type from NeoFS SDK package with the
protocol-generated message. This replaces all the business logic to
the application layer.
* Support error return. This allows to cover problem node states.
Return an error from `NodeState.ReadCurrentNetMap` method implemeted
through `atomic.Value` if `Store` method has not been called yet.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Use a simple loop at the callsite. This way we remove as much as we can.
Also, `Delete` metrics is more meaningful now.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
- Meta now supports (and requires) inc/dec labeled counters
- The new logic counter is incremented on `Put` operations and is
decremented on `Inhume` and `Delete` operations that are performed on
_stored_ objects only
- Allow force counters sync. "Force" mode should be used on metabase resync
and should not be used on a regular meta start
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
It will allow to use labeled object counters, e.g.: "phy" for all
the physically stored objects, "logic" for only available objects. Also, it
will allow to add typed (regular, TS, SG, LOCK) counters if needed.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Do not call `CalculateAction` for the eACL checks since it requires object
headers that are meaningless in the tree context.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
1. Do not require a request to be signed by the container owner if a
bearer token is missing
2. Do not check the system role since public requests are not expected to
be signed by IR or a container node (unlike the object requests)
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Sometimes it is useful to track sidechain events processed by the node.
For example, we need some easy way to look up for log messages about new
epoch notifications.
Make `subscriber.Subscriber` to log names of all events received from
the sidechain notification channel.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Re-configuration of Blobovnicza's object size limit must not affect
already stored objects. In previous implementation `Blobovnicza` didn't
see objects stored in buckets which became too big after size limit
re-configuration. For example, lets consider 1st configuration with 64KB
size limit for stored objects. Lets assume that we stored object of 64KB
size, and re-configured `Blobovnicza` with 32KB limit. After reboot
object should be still available, but actually it isn't. This is caused
by `Get` operation algorithm which iterates over configured size ranges
only, and doesn't process any other existing size bucket. By the way,
increasing of the object size limit didn't lead to the problem even in
previous implementation.
Make `Blobovnicza.Get` method to iterate over all size buckets
regardless of current configuration. This covers the described scenario.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Previously, the depth was restricted because with BFS the amount of
nodes we have in memory blows up exponentially. With DFS is is linear,
so we can process trees of arbitrary depth.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Some methods add "IR" suffix to its names in notary enabled envs
because of contract logic. It was broken due to incorrect notary state
reading (tryNotary != notary is enabled).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Set flush mark in the inside the flush worker because writing to the blobstor
can fail. Because each evicted object must be deleted, it is reasonable
to do this in the evict callback.
The evict callback is protected by LRU mutex and thus potentially interferes
with `Get` and `Iterate` methods. This problem will be addressed in the
future.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
There is a need to sync container-related caching mechanism with the
actual Sidechain changes. To do this, node should be able to listen
incoming notifications about container ops.
Define `PutSuccess` / `DeleteSuccess` notification event's parsers.
Subscribe to these events in node app. As initial implementation node
will log event receipts. Later handling is going to be practically
complicated.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Maintain an invariant that any blobovnicza is present either
in `opened` or in `active` map. Otherwise, the logic becomes too
complicate because it is not obvious when we should close the blobovnicza.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
This check should occur on the shard level, but because
blobstor components expose `Open(readOnly bool)` interface,
it is reasonable to expect an error here.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
If the file doesn't exist, return `apistatus.ObjectNotFound`.
First check is still there as a shortcut.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
This tests check that each blobstor component behaves similarly when
same methods are being used. It is intended to serve as a specification
for all future components.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Includes:
1. Renaming counter key to distinguish logical and physical objects
2. Version update dropping since changes could be done in a compatible way
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
1. Move compression parameters to the `shard` section.
2. Allow to use multiple sub-storage components in the blobstor.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
1. Remove in-memory cache. It doesn't persist objects and if we want
more speed, `NoSync` option can be used for the bolt DB.
2. Put to the metabase in a synchronous fashion. This considerably
simplifies overall logic and plays nicely with the metabase bolt DB
batch settings.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Allow to extend blobstor with more storage sub-systems. Currently
objects stored in the FSTree have empty byte slice descriptor and object
from blobovnicza tree have the same id as earlier. Each such change in
the identifier formation should be accompanied with metabase version
increase.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Close#1647.
Initially, `Sync: false` was provided because we can already lose
objects cached in memory. However, future changes in writecache will
remove inmemory cache and speed up it via other means.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
If an object is found in the Write-cache and is placed at the end of
the in-memory cache, the memory counter update operation tries to
dereference the index that is out of the sliced array. Moreover, even if
panic does not appear, the counter is updated with the wrong value.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Return all the objects on the empty common prefix search without search
optimizations that breaks boltDB logic.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
If an object has not been marked for removal by the GC in the current epoch
yet but has already expired, respond with `ErrObjectNotFound` api status.
Also, optimize shard iteration: a node must stop any iteration if the object
is found but gonna be removed soon.
All the checks are performed by the Metabase.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Sort the endpoint by their priority before the first WS client creation to
start the morph client with the highest priority endpoint.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Handling notification in a synchronous manner may lead to a blocking state
if a handler uses neo-go client.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Return listen errors in a synchronous fashion.
Another solution would be to use buffered channel, but this is not
scalable: for each new similar runner we would need to extend the
buffer.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
After a4adb79db new logical error could be returned. Do not increase
error counter in this case.
Signed-off-by: Evgenii Stratonikov <evgeniy@morphbits.ru>
Also, try to fetch object header info from the local storage to find as much
object info as possible for the requests which do not assume returning
object header as a response.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
If metabase can't be opened in the default mode, try opening shard
first in `ReadOnly` mode and then in `DegradedReadOnly`.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
`Degraded` mode can be set by the administrator if needed.
Modifying operations in this mode can lead node into an inconsistent state
because metabase checks such as lock checking are not performed.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
There is a need to support working w/o shard if it has problems with
blobovnicza tree.
Make `BlobStor.Init` to return new `ErrInitBlobovniczas` error. Remove
shard from storage engine's shard set if it returned this error from
`Init` call. So if some of the shards (but not all) return this error,
the node will be able to continue working without them.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Reduce public interface of this package. Later each result will contain
an additional status, so it makes more sense to use the same functions
and result processing everywhere.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Do not check that a node indeed belongs to the container, because the
synchronization will fail in this case anyway.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
1. Modifying operations are not expected to fail, unless the shard is
read-only.
2. `Get*` operations should increase error counter too, unless the
error is `ErrTreeNotFound`.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Do not return backend type from the service for now, because memory
backend is expected to vanish.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
The tricky part here is the engine itself: we stop iteration on
`ErrReadOnly` because it is better to synchronize the shard later than
to have partial trees stored in 2 shards.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Current implementation prevents invalid operations to become valid at
some later point (consider adding a child to the non-existent parent and
then adding the parent). This seems to diverge from the paper algorithm
and complicates implementation. Make it simpler.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
In case node is down or failing for some reason, we can expect `Dial` to
fail. In case we actively try to replicate and `Dial` always takes 2
seconds, replication-related channels quickly become full. That affects
latency of all other write operations.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Before this commit the replication channel was quickly filled under
heavy load. This lead to the continuously increasing latency for all
write operations. Now it looks better.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Also fix a bug with replicator using the multiaddress instead of
<host>:<port> format expected by gRPC library.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Currently to find a node by path we iterate over all the children on
each level. This is far from optimal and scales badly with the number of
nodes on a single level. Thus we introduce "indexed attributes" for
which an additional information is stored and which can be use in
`*ByPath` operations. Currently this set only includes `FileName`
attribute but this may change in future.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Consider a node `{FileName: "dir", Attribute: "xxx"}`. In case we add
a new node by path `["dir", "file.txt"]`, create a new intermediate node
with a single attribute.
`GetByPath` now also considers only nodes with a single attribute while building a path.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
