* update gateway-services table with endpoints
* fix failing test
* remove unneeded config in test
* rename "endpoint" to "destination"
* more endpoint renaming to destination in tests
* update isDestination based on service-defaults config entry creation
* use a 3 state kind to be able to set the kind to unknown (when neither a service or a destination exist)
* set unknown state to empty to avoid modifying alot of tests
* fix logic to set the kind correctly on CRUD
* fix failing tests
* add missing tests and fix service delete
* fix failing test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* fix a bug with kind and add relevant test
* fix compile error
* fix failing tests
* add kind to clone
* fix failing tests
* fix failing tests in catalog endpoint
* fix service dump test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* remove duplicate tests
* first draft of destinations intention in connect proxy
* remove ServiceDestinationList
* fix failing tests
* fix agent/consul failing tests
* change to filter intentions in the state store instead of adding a field.
* fix failing tests
* fix comment
* fix comments
* store service kind destination and add relevant tests
* changes based on review
* filter on destinations when querying source match
* change state store API to get an IntentionTarget parameter
* add intentions tests
* add destination upstream endpoint
* fix failing test
* fix failing test and a bug with wildcard intentions
* fix failing test
* Apply suggestions from code review
Co-authored-by: alex <8968914+acpana@users.noreply.github.com>
* add missing test and clarify doc
* fix style
* gofmt intention.go
* fix merge introduced issue
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
Co-authored-by: alex <8968914+acpana@users.noreply.github.com>
Co-authored-by: github-team-consul-core <github-team-consul-core@hashicorp.com>
* update gateway-services table with endpoints
* fix failing test
* remove unneeded config in test
* rename "endpoint" to "destination"
* more endpoint renaming to destination in tests
* update isDestination based on service-defaults config entry creation
* use a 3 state kind to be able to set the kind to unknown (when neither a service or a destination exist)
* set unknown state to empty to avoid modifying alot of tests
* fix logic to set the kind correctly on CRUD
* fix failing tests
* add missing tests and fix service delete
* fix failing test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* fix a bug with kind and add relevant test
* fix compile error
* fix failing tests
* add kind to clone
* fix failing tests
* fix failing tests in catalog endpoint
* fix service dump test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* remove duplicate tests
* first draft of destinations intention in connect proxy
* remove ServiceDestinationList
* fix failing tests
* fix agent/consul failing tests
* change to filter intentions in the state store instead of adding a field.
* fix failing tests
* fix comment
* fix comments
* store service kind destination and add relevant tests
* changes based on review
* filter on destinations when querying source match
* Apply suggestions from code review
Co-authored-by: alex <8968914+acpana@users.noreply.github.com>
* fix style
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* rename destinationType to targetType.
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
Co-authored-by: alex <8968914+acpana@users.noreply.github.com>
Co-authored-by: github-team-consul-core <github-team-consul-core@hashicorp.com>
Mesh gateways will now enable tcp connections with SNI names including peering information so that those connections may be proxied.
Note: this does not change the callers to use these mesh gateways.
There are a handful of changes in this commit:
* When querying trust bundles for a service we need to be able to
specify the namespace of the service.
* The endpoint needs to track the index because the cache watches use
it.
* Extracted bulk of the endpoint's logic to a state store function
so that index tracking could be tested more easily.
* Removed check for service existence, deferring that sort of work to ACL authz
* Added the cache type
Given that the exported-services config entry can use wildcards, the
precedence for wildcards is handled as with intentions. The most exact
match is the match that applies for any given service. We do not take
the union of all that apply.
Another update that was made was to reflect that only one
exported-services config entry applies to any given service in a
partition. This is a pre-existing constraint that gets enforced by
the Normalize() method on that config entry type.
For mTLS to work between two proxies in peered clusters with different root CAs,
proxies need to configure their outbound listener to use different root certificates
for validation.
Up until peering was introduced proxies would only ever use one set of root certificates
to validate all mesh traffic, both inbound and outbound. Now an upstream proxy
may have a leaf certificate signed by a CA that's different from the dialing proxy's.
This PR makes changes to proxycfg and xds so that the upstream TLS validation
uses different root certificates depending on which cluster is being dialed.
* update gateway-services table with endpoints
* fix failing test
* remove unneeded config in test
* rename "endpoint" to "destination"
* more endpoint renaming to destination in tests
* update isDestination based on service-defaults config entry creation
* use a 3 state kind to be able to set the kind to unknown (when neither a service or a destination exist)
* set unknown state to empty to avoid modifying alot of tests
* fix logic to set the kind correctly on CRUD
* fix failing tests
* add missing tests and fix service delete
* fix failing test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* fix a bug with kind and add relevant test
* fix compile error
* fix failing tests
* add kind to clone
* fix failing tests
* fix failing tests in catalog endpoint
* fix service dump test
* Apply suggestions from code review
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
* remove duplicate tests
* rename consts and fix kind when no destination is defined in the service-defaults.
* rename Kind to ServiceKind and change switch to use .(type)
Co-authored-by: Dan Stough <dan.stough@hashicorp.com>
OSS port of enterprise PR 1822
Includes the necessary changes to the `proxycfg` and `xds` packages to enable
Consul servers to configure arbitrary proxies using catalog data.
Broadly, `proxycfg.Manager` now has public methods for registering,
deregistering, and listing registered proxies — the existing local agent
state-sync behavior has been moved into a separate component that makes use of
these methods.
When an xDS session is started for a proxy service in the catalog, a goroutine
will be spawned to watch the service in the server's state store and
re-register it with the `proxycfg.Manager` whenever it is updated (and clean
it up when the client goes away).
Signed-off-by: acpana <8968914+acpana@users.noreply.github.com>
Co-authored-by: Chris S. Kim <ckim@hashicorp.com>
Co-authored-by: Freddy <freddygv@users.noreply.github.com>
Adds a new query param merge-central-config for use with the below endpoints:
/catalog/service/:service
/catalog/connect/:service
/health/service/:service
/health/connect/:service
If set on the request, the response will include a fully resolved service definition which is merged with the proxy-defaults/global and service-defaults/:service config entries (on-demand style). This is useful to view the full service definition for a mesh service (connect-proxy kind or gateway kind) which might not be merged before being written into the catalog (example: in case of services in the agentless model).
The importing peer will need to know what SNI and SPIFFE name
corresponds to each exported service. Additionally it will need to know
at a high level the protocol in use (L4/L7) to generate the appropriate
connection pool and local metrics.
For replicated connect synthetic entities we edit the `Connect{}` part
of a `NodeService` to have a new section:
{
"PeerMeta": {
"SNI": [
"web.default.default.owt.external.183150d5-1033-3672-c426-c29205a576b8.consul"
],
"SpiffeID": [
"spiffe://183150d5-1033-3672-c426-c29205a576b8.consul/ns/default/dc/dc1/svc/web"
],
"Protocol": "tcp"
}
}
This data is then replicated and saved as-is at the importing side. Both
SNI and SpiffeID are slices for now until I can be sure we don't need
them for how mesh gateways will ultimately work.
Occasionally we had seen the TestWatchServers_ACLToken_PermissionDenied be flagged as flaky in circleci. This change should fix that.
Why it fixes it is complicated. The test was failing with a panic when a mocked ACL Resolver was being called more times than expected. I struggled for a while to determine how that could be. This test should call authorize once and only once and the error returned should cause the stream to be terminated and the error returned to the gRPC client. Another oddity was no amount of running this test locally seemed to be able to reproduce the issue. I ran the test hundreds of thousands of time and it always passed.
It turns out that there is nothing wrong with the test. It just so happens that the panic from unexpected invocation of a mocked call happened during the test but was caused by a previous test (specifically the TestWatchServers_StreamLifecycle test)
The stream from the previous test remained open after all the test Cleanup functions were run and it just so happened that when the EventPublisher eventually picked up that the context was cancelled during cleanup, it force closes all subscriptions which causes some loops to be re-entered and the streams to be reauthorized. Its that looping in response to forced subscription closures that causes the mock to eventually panic. All the components, publisher, server, client all operate based on contexts. We cancel all those contexts but there is no syncrhonous way to know when they are stopped.
We could have implemented a syncrhonous stop but in the context of an actual running Consul, context cancellation + async stopping is perfectly fine. What we (Dan and I) eventually thought was that the behavior of grpc streams such as this when a server was shutting down wasn’t super helpful. What we would want is for a client to be able to distinguish between subscription closed because something may have changed requiring re-authentication and subscription closed because the server is shutting down. That way we can send back appropriate error messages to detail that the server is shutting down and not confuse users with potentially needing to resubscribe.
So thats what this PR does. We have introduced a shutting down state to our event subscriptions and the various streaming gRPC services that rely on the event publisher will all just behave correctly and actually stop the stream (not attempt transparent reauthorization) if this particular error is the one we get from the stream. Additionally the error that gets transmitted back through gRPC when this does occur indicates to the consumer that the server is going away. That is more helpful so that a client can then attempt to reconnect to another server.
Treat each exported service as a "discovery chain" and replicate one
synthetic CheckServiceNode for each chain and remote mesh gateway.
The health will be a flattened generated check of the checks for that
mesh gateway node.
Introduces two new public gRPC endpoints (`Login` and `Logout`) and
includes refactoring of the equivalent net/rpc endpoints to enable the
majority of logic to be reused (i.e. by extracting the `Binder` and
`TokenWriter` types).
This contains the OSS portions of the following enterprise commits:
- 75fcdbfcfa6af21d7128cb2544829ead0b1df603
- bce14b714151af74a7f0110843d640204082630a
- cc508b70fbf58eda144d9af3d71bd0f483985893
The primary bug here is in the streaming subsystem that makes the overall v1/health/service/:service request behave incorrectly when servicing a blocking request with a filter provided.
There is a secondary non-streaming bug being fixed here that is much less obvious related to when to update the `reply` variable in a `blockingQuery` evaluation. It is unlikely that it is triggerable in practical environments and I could not actually get the bug to manifest, but I fixed it anyway while investigating the original issue.
Simple reproduction (streaming):
1. Register a service with a tag.
curl -sL --request PUT 'http://localhost:8500/v1/agent/service/register' \
--header 'Content-Type: application/json' \
--data-raw '{ "ID": "ID1", "Name": "test", "Tags":[ "a" ], "EnableTagOverride": true }'
2. Do an initial filter query that matches on the tag.
curl -sLi --get 'http://localhost:8500/v1/health/service/test' --data-urlencode 'filter=a in Service.Tags'
3. Note you get one result. Use the `X-Consul-Index` header to establish
a blocking query in another terminal, this should not return yet.
curl -sLi --get 'http://localhost:8500/v1/health/service/test?index=$INDEX' --data-urlencode 'filter=a in Service.Tags'
4. Re-register that service with a different tag.
curl -sL --request PUT 'http://localhost:8500/v1/agent/service/register' \
--header 'Content-Type: application/json' \
--data-raw '{ "ID": "ID1", "Name": "test", "Tags":[ "b" ], "EnableTagOverride": true }'
5. Your blocking query from (3) should return with a header
`X-Consul-Query-Backend: streaming` and empty results if it works
correctly `[]`.
Attempts to reproduce with non-streaming failed (where you add `&near=_agent` to the read queries and ensure `X-Consul-Query-Backend: blocking-query` shows up in the results).
* update raft to v1.3.7
* add changelog
* fix compilation error
* fix HeartbeatTimeout
* fix ElectionTimeout to reload only if value is valid
* fix default values for `ElectionTimeout` and `HeartbeatTimeout`
* fix test defaults
* bump raft to v1.3.8
Adds a timeout (deadline) to client RPC calls, so that streams will no longer hang indefinitely in unstable network conditions.
Co-authored-by: kisunji <ckim@hashicorp.com>
* Implement the ServerDiscovery.WatchServers gRPC endpoint
* Fix the ConnectCA.Sign gRPC endpoints metadata forwarding.
* Unify public gRPC endpoints around the public.TraceID function for request_id logging
Adds a new gRPC endpoint to get envoy bootstrap params. The new consul-dataplane service will use this
endpoint to generate an envoy bootstrap configuration.
Whenever autopilot updates its state it notifies Consul. That notification will then trigger Consul to extract out the ready server information. If the ready servers have changed, then an event will be published to notify any subscribers of the full set of ready servers.
All these ready server event things are contained within an autopilotevents package instead of the consul package to make importing them into the grpc related packages possible
Introduces a gRPC endpoint for signing Connect leaf certificates. It's also
the first of the public gRPC endpoints to perform leader-forwarding, so
establishes the pattern of forwarding over the multiplexed internal RPC port.
Previously we had 1 EventPublisher per state.Store. When a state store was closed/abandoned such as during a consul snapshot restore, this had the behavior of force closing subscriptions for that topic and evicting event snapshots from the cache.
The intention of this commit is to keep all that behavior. To that end, the shared EventPublisher now supports the ability to refresh a topic. That will perform the force close + eviction. The FSM upon abandoning the previous state.Store will call RefreshTopic for all the topics with events generated by the state.Store.
Just like standard upstreams the order of applicability in descending precedence:
1. caller's `service-defaults` upstream override for destination
2. caller's `service-defaults` upstream defaults
3. destination's `service-resolver` ConnectTimeout
4. system default of 5s
Co-authored-by: mrspanishviking <kcardenas@hashicorp.com>
* Fixes a lint warning about t.Errorf not supporting %w
* Enable running autopilot on all servers
On the non-leader servers all they do is update the state and do not attempt any modifications.
* Fix the RPC conn limiting tests
Technically they were relying on racey behavior before. Now they should be reliable.
Adds a new gRPC service and endpoint to return the list of supported
consul dataplane features. The Consul Dataplane will use this API to
customize its interaction with that particular server.
Adds a new gRPC streaming endpoint (WatchRoots) that dataplane clients will
use to fetch the current list of active Connect CA roots and receive new
lists whenever the roots are rotated.
This adds an aws-iam auth method type which supports authenticating to Consul using AWS IAM identities.
Co-authored-by: R.B. Boyer <4903+rboyer@users.noreply.github.com>
* tlsutil: initial implementation of types/TLSVersion
tlsutil: add test for parsing deprecated agent TLS version strings
tlsutil: return TLSVersionInvalid with error
tlsutil: start moving tlsutil cipher suite lookups over to types/tls
tlsutil: rename tlsLookup to ParseTLSVersion, add cipherSuiteLookup
agent: attempt to use types in runtime config
agent: implement b.tlsVersion validation in config builder
agent: fix tlsVersion nil check in builder
tlsutil: update to renamed ParseTLSVersion and goTLSVersions
tlsutil: fixup TestConfigurator_CommonTLSConfigTLSMinVersion
tlsutil: disable invalid config parsing tests
tlsutil: update tests
auto_config: lookup old config strings from base.TLSMinVersion
auto_config: update endpoint tests to use TLS types
agent: update runtime_test to use TLS types
agent: update TestRuntimeCinfig_Sanitize.golden
agent: update config runtime tests to expect TLS types
* website: update Consul agent tls_min_version values
* agent: fixup TLS parsing and compilation errors
* test: fixup lint issues in agent/config_runtime_test and tlsutil/config_test
* tlsutil: add CHACHA20_POLY1305 cipher suites to goTLSCipherSuites
* test: revert autoconfig tls min version fixtures to old format
* types: add TLSVersions public function
* agent: add warning for deprecated TLS version strings
* agent: move agent config specific logic from tlsutil.ParseTLSVersion into agent config builder
* tlsutil(BREAKING): change default TLS min version to TLS 1.2
* agent: move ParseCiphers logic from tlsutil into agent config builder
* tlsutil: remove unused CipherString function
* agent: fixup import for types package
* Revert "tlsutil: remove unused CipherString function"
This reverts commit 6ca7f6f58d268e617501b7db9500113c13bae70c.
* agent: fixup config builder and runtime tests
* tlsutil: fixup one remaining ListenerConfig -> ProtocolConfig
* test: move TLS cipher suites parsing test from tlsutil into agent config builder tests
* agent: remove parseCiphers helper from auto_config_endpoint_test
* test: remove unused imports from tlsutil
* agent: remove resolved FIXME comment
* tlsutil: remove TODO and FIXME in cipher suite validation
* agent: prevent setting inherited cipher suite config when TLS 1.3 is specified
* changelog: add entry for converting agent config to TLS types
* agent: remove FIXME in runtime test, this is covered in builder tests with invalid tls9 value now
* tlsutil: remove config tests for values checked at agent config builder boundary
* tlsutil: remove tls version check from loadProtocolConfig
* tlsutil: remove tests and TODOs for logic checked in TestBuilder_tlsVersion and TestBuilder_tlsCipherSuites
* website: update search link for supported Consul agent cipher suites
* website: apply review suggestions for tls_min_version description
* website: attempt to clean up markdown list formatting for tls_min_version
* website: moar linebreaks to fix tls_min_version formatting
* Revert "website: moar linebreaks to fix tls_min_version formatting"
This reverts commit 38585927422f73ebf838a7663e566ac245f2a75c.
* autoconfig: translate old values for TLSMinVersion
* agent: rename var for translated value of deprecated TLS version value
* Update agent/config/deprecated.go
Co-authored-by: Dan Upton <daniel@floppy.co>
* agent: fix lint issue
* agent: fixup deprecated config test assertions for updated warning
Co-authored-by: Dan Upton <daniel@floppy.co>
Looks like something got munged at some point. Not sure how it slipped in, but my best guess is that because TestTxn_Apply_ACLDeny is marked flaky we didn't block merge because it failed.
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
This extends the acl.AllowAuthorizer with source of authority information.
The next step is to unify the AllowAuthorizer and ACLResolveResult structures; that will be done in a separate PR.
Part of #12481
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
Introduces the capability to configure TLS differently for Consul's
listeners/ports (i.e. HTTPS, gRPC, and the internal multiplexed RPC
port) which is useful in scenarios where you may want the HTTPS or
gRPC interfaces to present a certificate signed by a well-known/public
CA, rather than the certificate used for internal communication which
must have a SAN in the form `server.<dc>.consul`.
Currently the config_entry.go subsystem delegates authorization decisions via the ConfigEntry interface CanRead and CanWrite code. Unfortunately this returns a true/false value and loses the details of the source.
This is not helpful, especially since it the config subsystem can be more complex to understand, since it covers so many domains.
This refactors CanRead/CanWrite to return a structured error message (PermissionDenied or the like) with more details about the reason for denial.
Part of #12241
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* First pass for helper for bulk changes
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Convert ACLRead and ACLWrite to new form
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* AgentRead and AgentWRite
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Fix EventWrite
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* KeyRead, KeyWrite, KeyList
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* KeyRing
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* NodeRead NodeWrite
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* OperatorRead and OperatorWrite
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* PreparedQuery
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Intention partial
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Fix ServiceRead, Write ,etc
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Error check ServiceRead?
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Fix Sessionread/Write
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Fixup snapshot ACL
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Error fixups for txn
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Add changelog
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
* Fixup review comments
Signed-off-by: Mark Anderson <manderson@hashicorp.com>
Improves tests from #12362
These tests try to setup the following concurrent scenario:
1. (goroutine 1) execute read RPC with index=0
2. (goroutine 1) get response from (1) @ index=10
3. (goroutine 1) execute read RPC with index=10 and block
4. (goroutine 2) WHILE (3) is blocking, start slamming the system with stray writes that will cause the WatchSet to wakeup
5. (goroutine 2) after doing all writes, shut down the reader above
6. (goroutine 1) stops reading, double checks that it only ever woke up once (from 1)
Minor fix for behavior in #12362
IsDefault sometimes returns true even if there was a proxy-defaults or service-defaults config entry that was consulted. This PR fixes that.
before:
$ go test ./agent/consul -run TestLeader_ReapOrLeftMember_IgnoreSelf
ok github.com/hashicorp/consul/agent/consul 21.147s
after:
$ go test ./agent/consul -run TestLeader_ReapOrLeftMember_IgnoreSelf
ok github.com/hashicorp/consul/agent/consul 5.402s
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)
Many places in consul already treated node names case insensitively.
The state store indexes already do it, but there are a few places that
did a direct byte comparison which have now been corrected.
One place of particular consideration is ensureCheckIfNodeMatches
which is executed during snapshot restore (among other places). If a
node check used a slightly different casing than the casing of the node
during register then the snapshot restore here would deterministically
fail. This has been fixed.
Primary approach:
git grep -i "node.*[!=]=.*node" -- ':!*_test.go' ':!docs'
git grep -i '\[[^]]*member[^]]*\]
git grep -i '\[[^]]*\(member\|name\|node\)[^]]*\]' -- ':!*_test.go' ':!website' ':!ui' ':!agent/proxycfg/testing.go:' ':!*.md'
There are some cross-config-entry relationships that are enforced during
"graph validation" at persistence time that are required to be
maintained. This means that config entries may form a digraph at times.
Config entry replication procedes in a particular sorted order by kind
and name.
Occasionally there are some fixups to these digraphs that end up
replicating in the wrong order and replicating the leaves
(ingress-gateway) before the roots (service-defaults) leading to
replication halting due to a graph validation error related to things
like mismatched service protocol requirements.
This PR changes replication to give each computed change (upsert/delete)
a fair shot at being applied before deciding to terminate that round of
replication in error. In the case where we've simply tried to do the
operations in the wrong order at least ONE of the outstanding requests
will complete in the right order, leading the subsequent round to have
fewer operations to do, with a smaller likelihood of graph validation
errors.
This does not address all scenarios, but for scenarios where the edits
are being applied in the wrong order this should avoid replication
halting.
Fixes#9319
The scenario that is NOT ADDRESSED by this PR is as follows:
1. create: service-defaults: name=new-web, protocol=http
2. create: service-defaults: name=old-web, protocol=http
3. create: service-resolver: name=old-web, redirect-to=new-web
4. delete: service-resolver: name=old-web
5. update: service-defaults: name=old-web, protocol=grpc
6. update: service-defaults: name=new-web, protocol=grpc
7. create: service-resolver: name=old-web, redirect-to=new-web
If you shutdown dc2 just before (4) and turn it back on after (7)
replication is impossible as there is no single edit you can make to
make forward progress.
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.
Dhia Ayachi