Starting from and extending the mechanism introduced in #12110 we can specially handle the 3 main special Consul RPC endpoints that react to many config entries in a single blocking query in Connect:
- `DiscoveryChain.Get`
- `ConfigEntry.ResolveServiceConfig`
- `Intentions.Match`
All of these will internally watch for many config entries, and at least one of those will likely be not found in any given query. Because these are blends of multiple reads the exact solution from #12110 isn't perfectly aligned, but we can tweak the approach slightly and regain the utility of that mechanism.
### No Config Entries Found
In this case, despite looking for many config entries none may be found at all. Unlike #12110 in this scenario we do not return an empty reply to the caller, but instead synthesize a struct from default values to return. This can be handled nearly identically to #12110 with the first 1-2 replies being non-empty payloads followed by the standard spurious wakeup suppression mechanism from #12110.
### No Change Since Last Wakeup
Once a blocking query loop on the server has completed and slept at least once, there is a further optimization we can make here to detect if any of the config entries that were present at specific versions for the prior execution of the loop are identical for the loop we just woke up for. In that scenario we can return a slightly different internal sentinel error and basically externally handle it similar to #12110.
This would mean that even if 20 discovery chain read RPC handling goroutines wakeup due to the creation of an unrelated config entry, the only ones that will terminate and reply with a blob of data are those that genuinely have new data to report.
### Extra Endpoints
Since this pattern is pretty reusable, other key config-entry-adjacent endpoints used by `agent/proxycfg` also were updated:
- `ConfigEntry.List`
- `Internal.IntentionUpstreams` (tproxy)
Otherwise when the query times out we might incorrectly send a value for
the reply, when we should send an empty reply.
Also document errNotFound and how to handle the result in that case.
By using the query results as state.
Blocking queries are efficient when the query matches some results,
because the ModifyIndex of those results, returned as queryMeta.Mindex,
will never change unless the items themselves change.
Blocking queries for non-existent items are not efficient because the
queryMeta.Index can (and often does) change when other entities are
written.
This commit reduces the churn of these queries by using a different
comparison for "has changed". Instead of using the modified index, we
use the existence of the results. If the previous result was "not found"
and the new result is still "not found", we know we can ignore the
modified index and continue to block.
This is done by setting the minQueryIndex to the returned
queryMeta.Index, which prevents the query from returning before a state
change is observed.
Follow the Go convention of accepting a small interface that documents
the methods used by the function.
Clarify the rules for implementing a query function passed to
blockingQuery.
This commit syncs ENT changes to the OSS repo.
Original commit details in ENT:
```
commit 569d25f7f4578981c3801e6e067295668210f748
Author: FFMMM <FFMMM@users.noreply.github.com>
Date: Thu Feb 10 10:23:33 2022 -0800
Vendor fork net rpc (#1538)
* replace net/rpc w consul-net-rpc/net/rpc
Signed-off-by: FFMMM <FFMMM@users.noreply.github.com>
* replace msgpackrpc and go-msgpack with fork from mono repo
Signed-off-by: FFMMM <FFMMM@users.noreply.github.com>
* gofmt all files touched
Signed-off-by: FFMMM <FFMMM@users.noreply.github.com>
```
Signed-off-by: FFMMM <FFMMM@users.noreply.github.com>
Remove some unnecessary comments around query_blocking metric. The only
line that needs any comments in the atomic decrement.
Cleanup the block and return comments and logic. The old comment about
AbandonCh may have been relevant before, but it is expected behaviour
now.
The logic was simplified by inverting the err condition.
This helps keep the logic in blockingQuery more focused. In the future we
may have a separate struct for RPC queries which may allow us to move this
off of Server.
This safeguard should be safe to apply in general. We are already
applying it to non-blocking queries that call blockingQuery, so it
should be fine to apply it to others.
To remove the TODO, and make it more readable.
In general this reduces the scope of variables, making them easier to reason about.
It also introduces more early returns so that we can see the flow from the structure
of the function.
The query metrics are actually reported for all read queries, not only
ones that use a MinIndex to block for updates.
Also clarify the raft.apply metric is only on the leader.
Also accept an RPCInfo instead of interface{}. Accepting an interface
lead to a bug where the caller was expecting the arg to be the response
when in fact it was always passed the request. By accepting RPCInfo
it should indicate that this is actually the request value.
One caller of canRetry already passed an RPCInfo, the second handles
the type assertion before calling canRetry.
Previously canRetry was attempting to retrieve this error from args, however there was never
any callers that would pass an error to args.
With the change to raftApply to move this error to the error return value, it is now possible
to receive this error from the err argument.
This commit updates canRetry to check for ErrChunkingResubmit in err.
Previously we were inconsistently checking the response for errors. This
PR moves the response-is-error check into raftApply, so that all callers
can look at only the error response, instead of having to know that
errors could come from two places.
This should expose a few more errors that were previously hidden because
in some calls to raftApply we were ignoring the response return value.
Also handle errors more consistently. In some cases we would log the
error before returning it. This can be very confusing because it can
result in the same error being logged multiple times. Instead return
a wrapped error.
This can happen when one other node in the cluster such as a client is unable to communicate with the leader server and sees it as failed. When that happens its failing status eventually gets propagated to the other servers in the cluster and eventually this can result in RPCs returning “No cluster leader” error.
That error is misleading and unhelpful for determing the root cause of the issue as its not raft stability but rather and client -> server networking issue. Therefore this commit will add a new error that will be returned in that case to differentiate between the two cases.
* changes some functions to return data instead of modifying pointer
arguments
* renames globalRPC() to keyringRPCs() to make its purpose more clear
* restructures KeyringOperation() to make it more understandable
The version field has been used to decide which multiplexing to use. It
was introduced in 2457293dceec95ecd12ef4f01442e13710ea131a. But this is
6y ago and there is no need for this differentiation anymore.
This is like a Möbius strip of code due to the fact that low-level components (serf/memberlist) are connected to high-level components (the catalog and mesh-gateways) in a twisty maze of references which make it hard to dive into. With that in mind here's a high level summary of what you'll find in the patch:
There are several distinct chunks of code that are affected:
* new flags and config options for the server
* retry join WAN is slightly different
* retry join code is shared to discover primary mesh gateways from secondary datacenters
* because retry join logic runs in the *agent* and the results of that
operation for primary mesh gateways are needed in the *server* there are
some methods like `RefreshPrimaryGatewayFallbackAddresses` that must occur
at multiple layers of abstraction just to pass the data down to the right
layer.
* new cache type `FederationStateListMeshGatewaysName` for use in `proxycfg/xds` layers
* the function signature for RPC dialing picked up a new required field (the
node name of the destination)
* several new RPCs for manipulating a FederationState object:
`FederationState:{Apply,Get,List,ListMeshGateways}`
* 3 read-only internal APIs for debugging use to invoke those RPCs from curl
* raft and fsm changes to persist these FederationStates
* replication for FederationStates as they are canonically stored in the
Primary and replicated to the Secondaries.
* a special derivative of anti-entropy that runs in secondaries to snapshot
their local mesh gateway `CheckServiceNodes` and sync them into their upstream
FederationState in the primary (this works in conjunction with the
replication to distribute addresses for all mesh gateways in all DCs to all
other DCs)
* a "gateway locator" convenience object to make use of this data to choose
the addresses of gateways to use for any given RPC or gossip operation to a
remote DC. This gets data from the "retry join" logic in the agent and also
directly calls into the FSM.
* RPC (`:8300`) on the server sniffs the first byte of a new connection to
determine if it's actually doing native TLS. If so it checks the ALPN header
for protocol determination (just like how the existing system uses the
type-byte marker).
* 2 new kinds of protocols are exclusively decoded via this native TLS
mechanism: one for ferrying "packet" operations (udp-like) from the gossip
layer and one for "stream" operations (tcp-like). The packet operations
re-use sockets (using length-prefixing) to cut down on TLS re-negotiation
overhead.
* the server instances specially wrap the `memberlist.NetTransport` when running
with gateway federation enabled (in a `wanfed.Transport`). The general gist is
that if it tries to dial a node in the SAME datacenter (deduced by looking
at the suffix of the node name) there is no change. If dialing a DIFFERENT
datacenter it is wrapped up in a TLS+ALPN blob and sent through some mesh
gateways to eventually end up in a server's :8300 port.
* a new flag when launching a mesh gateway via `consul connect envoy` to
indicate that the servers are to be exposed. This sets a special service
meta when registering the gateway into the catalog.
* `proxycfg/xds` notice this metadata blob to activate additional watches for
the FederationState objects as well as the location of all of the consul
servers in that datacenter.
* `xds:` if the extra metadata is in place additional clusters are defined in a
DC to bulk sink all traffic to another DC's gateways. For the current
datacenter we listen on a wildcard name (`server.<dc>.consul`) that load
balances all servers as well as one mini-cluster per node
(`<node>.server.<dc>.consul`)
* the `consul tls cert create` command got a new flag (`-node`) to help create
an additional SAN in certs that can be used with this flavor of federation.
* agent: measure blocking queries
* agent.rpc: update docs to mention we only record blocking queries
* agent.rpc: make go fmt happy
* agent.rpc: fix non-atomic read and decrement with bitwise xor of uint64 0
* agent.rpc: clarify review question
* agent.rpc: today I learned that one must declare all variables before interacting with goto labels
* Update agent/consul/server.go
agent.rpc: more precise comment on `Server.queriesBlocking`
Co-Authored-By: Paul Banks <banks@banksco.de>
* Update website/source/docs/agent/telemetry.html.md
agent.rpc: improve queries_blocking description
Co-Authored-By: Paul Banks <banks@banksco.de>
* agent.rpc: fix some bugs found in review
* add a note about the updated counter behavior to telemetry.md
* docs: add upgrade-specific note on consul.rpc.quer{y,ies_blocking} behavior
Co-authored-by: Paul Banks <banks@banksco.de>
We set RawToString=true so that []uint8 => string when decoding an interface{}.
We set the MapType so that map[interface{}]interface{} decodes to map[string]interface{}.
Add tests to ensure that this doesn't break existing usages.
Fixes#7223
Sometimes, we have lots of errors in cross calls between DCs (several hundreds / sec)
Enrich the log in order to help diagnose the root cause of issue.
Main Changes:
• method signature updates everywhere to account for passing around enterprise meta.
• populate the EnterpriseAuthorizerContext for all ACL related authorizations.
• ACL resource listings now operate like the catalog or kv listings in that the returned entries are filtered down to what the token is allowed to see. With Namespaces its no longer all or nothing.
• Modified the acl.Policy parsing to abstract away basic decoding so that enterprise can do it slightly differently. Also updated method signatures so that when parsing a policy it can take extra ent metadata to use during rules validation and policy creation.
Secondary Changes:
• Moved protobuf encoding functions out of the agentpb package to eliminate circular dependencies.
• Added custom JSON unmarshalers for a few ACL resource types (to support snake case and to get rid of mapstructure)
• AuthMethod validator cache is now an interface as these will be cached per-namespace for Consul Enterprise.
• Added checks for policy/role link existence at the RPC API so we don’t push the request through raft to have it fail internally.
• Forward ACL token delete request to the primary datacenter when the secondary DC doesn’t have the token.
• Added a bunch of ACL test helpers for inserting ACL resource test data.
In a previous PR I made it so that we had interfaces that would work enough to allow blockingQueries to work. However to complete this we need all fields to be settable and gettable.
Notes:
• If Go ever gets contracts/generics then we could get rid of all the Getters/Setters
• protoc / protoc-gen-gogo are going to generate all the getters for us.
• I copied all the getters/setters from the protobuf funcs into agent/structs/protobuf_compat.go
• Also added JSON marshaling funcs that use jsonpb for protobuf types.
* Add build system support for protobuf generation
This is done generically so that we don’t have to keep updating the makefile to add another proto generation.
Note: anything not in the vendor directory and with a .proto extension will be run through protoc if the corresponding namespace.pb.go file is not up to date.
If you want to rebuild just a single proto file you can do so with: make proto-rebuild PROTOFILES=<list of proto files to rebuild>
Providing the PROTOFILES var will override the default behavior of finding all the .proto files.
* Start adding types to the agent/proto package
These will be needed for some other work and are by no means comprehensive.
* Add ability to resolve/fixup the agentpb.ACLLinks structure in the state store.
* Use protobuf marshalling of raft requests instead of msgpack for protoc generated types.
This does not change any encoding of existing types.
* Removed structs package automatically encoding with protobuf marshalling
Instead the caller of raftApply that wants to opt-in to protobuf encoding will have to call `raftApplyProtobuf`
* Run update-vendor to fixup modules.txt
Nothing changed as far as dependencies go but the ordering of modules in that file depends on the time they are first seen and its not alphabetical.
* Rename some things and implement the structs.RPCInfo interface bits
agentpb.QueryOptions and agentpb.WriteRequest implement 3 of the 4 RPCInfo funcs and the new TargetDatacenter message type implements the fourth.
* Use the right encoding function.
* Renamed agent/proto package to agent/agentpb to prevent package name conflicts
* Update modules.txt to fix ordering
* Change blockingQuery to take in interfaces for the query options and meta
* Add %T to error output.
* Add/Update some comments
Chris S. Kim