This adds two ways to check for subscription support. First, one can now check
whether the transport method (HTTP/WS/etc.) is capable of subscriptions using
the new Client.SupportsSubscriptions method.
Second, the error returned by Subscribe can now reliably be tested using this
pattern:
sub, err := client.Subscribe(...)
if errors.Is(err, rpc.ErrNotificationsUnsupported) {
// no subscription support
}
---------
Co-authored-by: Felix Lange <fjl@twurst.com>
This PR adds server-side limits for JSON-RPC batch requests. Before this change, batches
were limited only by processing time. The server would pick calls from the batch and
answer them until the response timeout occurred, then stop processing the remaining batch
items.
Here, we are adding two additional limits which can be configured:
- the 'item limit': batches can have at most N items
- the 'response size limit': batches can contain at most X response bytes
These limits are optional in package rpc. In Geth, we set a default limit of 1000 items
and 25MB response size.
When a batch goes over the limit, an error response is returned to the client. However,
doing this correctly isn't always possible. In JSON-RPC, only method calls with a valid
`id` can be responded to. Since batches may also contain non-call messages or
notifications, the best effort thing we can do to report an error with the batch itself is
reporting the limit violation as an error for the first method call in the batch. If a batch is
too large, but contains only notifications and responses, the error will be reported with
a null `id`.
The RPC client was also changed so it can deal with errors resulting from too large
batches. An older client connected to the server code in this PR could get stuck
until the request timeout occurred when the batch is too large. **Upgrading to a version
of the RPC client containing this change is strongly recommended to avoid timeout issues.**
For some weird reason, when writing the original client implementation, @fjl worked off of
the assumption that responses could be distributed across batches arbitrarily. So for a
batch request containing requests `[A B C]`, the server could respond with `[A B C]` but
also with `[A B] [C]` or even `[A] [B] [C]` and it wouldn't make a difference to the
client.
So in the implementation of BatchCallContext, the client waited for all requests in the
batch individually. If the server didn't respond to some of the requests in the batch, the
client would eventually just time out (if a context was used).
With the addition of batch limits into the server, we anticipate that people will hit this
kind of error way more often. To handle this properly, the client now waits for a single
response batch and expects it to contain all responses to the requests.
---------
Co-authored-by: Felix Lange <fjl@twurst.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>
Here we add special handling for sending an error response when the write timeout of the
HTTP server is just about to expire. This is surprisingly difficult to get right, since is
must be ensured that all output is fully flushed in time, which needs support from
multiple levels of the RPC handler stack:
The timeout response can't use chunked transfer-encoding because there is no way to write
the final terminating chunk. net/http writes it when the topmost handler returns, but the
timeout will already be over by the time that happens. We decided to disable chunked
encoding by setting content-length explicitly.
Gzip compression must also be disabled for timeout responses because we don't know the
true content-length before compressing all output, i.e. compression would reintroduce
chunked transfer-encoding.
This changes the CI / release builds to use the latest Go version. It also
upgrades golangci-lint to a newer version compatible with Go 1.19.
In Go 1.19, godoc has gained official support for links and lists. The
syntax for code blocks in doc comments has changed and now requires a
leading tab character. gofmt adapts comments to the new syntax
automatically, so there are a lot of comment re-formatting changes in this
PR. We need to apply the new format in order to pass the CI lint stage with
Go 1.19.
With the linter upgrade, I have decided to disable 'gosec' - it produces
too many false-positive warnings. The 'deadcode' and 'varcheck' linters
have also been removed because golangci-lint warns about them being
unmaintained. 'unused' provides similar coverage and we already have it
enabled, so we don't lose much with this change.
This changes the error code returned by the RPC server in certain situations:
- handler panic: code -32603
- result marshaling error: code -32603
- attempt to subscribe via HTTP: code -32001
In all of the above cases, the server previously returned the default error
code -32000.
Co-authored-by: Nicholas Zhao <nicholas.zhao@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This fixes a rare issue where the client subscription forwarding loop
would attempt send on the subscription's channel after Unsubscribe has
returned, leading to a panic if the subscription channel was already
closed by the user. Example:
sub, _ := client.Subscribe(..., channel, ...)
sub.Unsubscribe()
close(channel)
The race occurred because Unsubscribe called quitWithServer to tell the
forwarding loop to stop sending on sub.channel, but did not wait for the
loop to actually come down. This is fixed by adding an additional channel
to track the shutdown, on which Unsubscribe now waits.
Fixes#22322
* internal/ethapi: return revert reason for eth_call
* internal/ethapi: moved revert reason logic to doCall
* accounts/abi/bind/backends: added revert reason logic to simulated backend
* internal/ethapi: fixed linting error
* internal/ethapi: check if require reason can be unpacked
* internal/ethapi: better error logic
* internal/ethapi: simplify logic
* internal/ethapi: return vmError()
* internal/ethapi: move handling of revert out of docall
* graphql: removed revert logic until spec change
* rpc: internal/ethapi: added custom error types
* graphql: use returndata instead of return
Return() checks if there is an error. If an error is found, we return nil.
For most use cases it can be beneficial to return the output even if there
was an error. This code should be changed anyway once the spec supports
error reasons in graphql responses
* accounts/abi/bind/backends: added tests for revert reason
* internal/ethapi: add errorCode to revert error
* internal/ethapi: add errorCode of 3 to revertError
* internal/ethapi: unified estimateGasErrors, simplified logic
* internal/ethapi: unified handling of errors in DoEstimateGas
* rpc: print error data field
* accounts/abi/bind/backends: unify simulatedBackend and RPC
* internal/ethapi: added binary data to revertError data
* internal/ethapi: refactored unpacking logic into newRevertError
* accounts/abi/bind/backends: fix EstimateGas
* accounts, console, internal, rpc: minor error interface cleanups
* Revert "accounts, console, internal, rpc: minor error interface cleanups"
This reverts commit 2d3ef53c5304e429a04983210a417c1f4e0dafb7.
* re-apply the good parts of 2d3ef53c53
* rpc: add test for returning server error data from client
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This adds a couple of metrics for tracking the timing
and frequency of method calls:
- rpc/requests gauge counts all requests
- rpc/success gauge counts requests which return err == nil
- rpc/failure gauge counts requests which return err != nil
- rpc/duration/all timer tracks timing of all requests
- rpc/duration/<method>/<success/failure> tracks per-method timing
* rpc: remove 'exported or builtin' restriction for parameters
There is no technial reason for this restriction because package reflect
can create values of any type. Requiring parameters and return values to
be exported causes a lot of noise in package exports.
* rpc: fix staticcheck warnings
* rpc: improve codec abstraction
rpc.ServerCodec is an opaque interface. There was only one way to get a
codec using existing APIs: rpc.NewJSONCodec. This change exports
newCodec (as NewFuncCodec) and NewJSONCodec (as NewCodec). It also makes
all codec methods non-public to avoid showing internals in godoc.
While here, remove codec options in tests because they are not
supported anymore.
* p2p/simulations: use github.com/gorilla/websocket
This package was the last remaining user of golang.org/x/net/websocket.
Migrating to the new library wasn't straightforward because it is no
longer possible to treat WebSocket connections as a net.Conn.
* vendor: delete golang.org/x/net/websocket
* rpc: fix godoc comments and run gofmt
New APIs added:
client.RegisterName(namespace, service) // makes service available to server
client.Notify(ctx, method, args...) // sends a notification
ClientFromContext(ctx) // to get a client in handler method
This is essentially a rewrite of the server-side code. JSON-RPC
processing code is now the same on both server and client side. Many
minor issues were fixed in the process and there is a new test suite for
JSON-RPC spec compliance (and non-compliance in some cases).
List of behavior changes:
- Method handlers are now called with a per-request context instead of a
per-connection context. The context is canceled right after the method
returns.
- Subscription error channels are always closed when the connection
ends. There is no need to also wait on the Notifier's Closed channel
to detect whether the subscription has ended.
- Client now omits "params" instead of sending "params": null when there
are no arguments to a call. The previous behavior was not compliant
with the spec. The server still accepts "params": null.
- Floating point numbers are allowed as "id". The spec doesn't allow
them, but we handle request "id" as json.RawMessage and guarantee that
the same number will be sent back.
- Logging is improved significantly. There is now a message at DEBUG
level for each RPC call served.
