This PR adds a WebSocket grid feature that allows servers to communicate via
a single two-way connection.
There are two request types:
* Single requests, which are `[]byte => ([]byte, error)`. This is for efficient small
roundtrips with small payloads.
* Streaming requests which are `[]byte, chan []byte => chan []byte (and error)`,
which allows for different combinations of full two-way streams with an initial payload.
Only a single stream is created between two machines - and there is, as such, no
server/client relation since both sides can initiate and handle requests. Which server
initiates the request is decided deterministically on the server names.
Requests are made through a mux client and server, which handles message
passing, congestion, cancelation, timeouts, etc.
If a connection is lost, all requests are canceled, and the calling server will try
to reconnect. Registered handlers can operate directly on byte
slices or use a higher-level generics abstraction.
There is no versioning of handlers/clients, and incompatible changes should
be handled by adding new handlers.
The request path can be changed to a new one for any protocol changes.
First, all servers create a "Manager." The manager must know its address
as well as all remote addresses. This will manage all connections.
To get a connection to any remote, ask the manager to provide it given
the remote address using.
```
func (m *Manager) Connection(host string) *Connection
```
All serverside handlers must also be registered on the manager. This will
make sure that all incoming requests are served. The number of in-flight
requests and responses must also be given for streaming requests.
The "Connection" returned manages the mux-clients. Requests issued
to the connection will be sent to the remote.
* `func (c *Connection) Request(ctx context.Context, h HandlerID, req []byte) ([]byte, error)`
performs a single request and returns the result. Any deadline provided on the request is
forwarded to the server, and canceling the context will make the function return at once.
* `func (c *Connection) NewStream(ctx context.Context, h HandlerID, payload []byte) (st *Stream, err error)`
will initiate a remote call and send the initial payload.
```Go
// A Stream is a two-way stream.
// All responses *must* be read by the caller.
// If the call is canceled through the context,
//The appropriate error will be returned.
type Stream struct {
// Responses from the remote server.
// Channel will be closed after an error or when the remote closes.
// All responses *must* be read by the caller until either an error is returned or the channel is closed.
// Canceling the context will cause the context cancellation error to be returned.
Responses <-chan Response
// Requests sent to the server.
// If the handler is defined with 0 incoming capacity this will be nil.
// Channel *must* be closed to signal the end of the stream.
// If the request context is canceled, the stream will no longer process requests.
Requests chan<- []byte
}
type Response struct {
Msg []byte
Err error
}
```
There are generic versions of the server/client handlers that allow the use of type
safe implementations for data types that support msgpack marshal/unmarshal.
PUT calls cannot afford to have large latency build-ups due
to contentious usage.json, or worse letting them fail with
some unexpected error, this can happen when this file is
concurrently being updated via scanner or it is being
healed during a disk replacement heal.
However, these are fairly quick in theory, stressed clusters
can quickly show visible latency this can add up leading to
invalid errors returned during PUT.
It is perhaps okay for us to relax this error return requirement
instead, make sure that we log that we are proceeding to take in
the requests while the quota is using an older value for the quota
enforcement. These things will reconcile themselves eventually,
via scanner making sure to overwrite the usage.json.
Bonus: make sure that storage-rest-client sets ExpectTimeouts to
be 'true', such that DiskInfo() call with contextTimeout does
not prematurely disconnect the servers leading to a longer
healthCheck, back-off routine. This can easily pile up while also
causing active callers to disconnect, leading to quorum loss.
DiskInfo is actively used in the PUT, Multipart call path for
upgrading parity when disks are down, it in-turn shouldn't cause
more disks to go down.
minio_inter_node_traffic_errors_total currently does not track
requests body write/read errors of internode REST communications.
This commit fixes this by wrapping resp.Body.
fixes#15334
- re-use net/url parsed value for http.Request{}
- remove gosimple, structcheck and unusued due to https://github.com/golangci/golangci-lint/issues/2649
- unwrapErrs upto leafErr to ensure that we store exactly the correct errors
it would seem like using `bufio.Scan()` is very
slow for heavy concurrent I/O, ie. when r.Body
is slow , instead use a proper
binary exchange format, to marshal and unmarshal
the LockArgs datastructure in a cleaner way.
this PR increases performance of the locking
sub-system for tiny repeated read lock requests
on same object.
```
BenchmarkLockArgs
BenchmarkLockArgs-4 6417609 185.7 ns/op 56 B/op 2 allocs/op
BenchmarkLockArgsOld
BenchmarkLockArgsOld-4 1187368 1015 ns/op 4096 B/op 1 allocs/op
```
This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`
Klaus Post
Aditya Manthramurthy
Harshavardhana
jiuker
Anis Eleuch
ebozduman