## Issue Addressed
NA
## Proposed Changes
Rather than spawning new tasks on the tokio executor to process each HTTP API request, send the tasks to the `BeaconProcessor`. This achieves:
1. Places a bound on how many concurrent requests are being served (i.e., how many we are actually trying to compute at one time).
1. Places a bound on how many requests can be awaiting a response at one time (i.e., starts dropping requests when we have too many queued).
1. Allows the BN prioritise HTTP requests with respect to messages coming from the P2P network (i.e., proiritise importing gossip blocks rather than serving API requests).
Presently there are two levels of priorities:
- `Priority::P0`
- The beacon processor will prioritise these above everything other than importing new blocks.
- Roughly all validator-sensitive endpoints.
- `Priority::P1`
- The beacon processor will prioritise practically all other P2P messages over these, except for historical backfill things.
- Everything that's not `Priority::P0`
The `--http-enable-beacon-processor false` flag can be supplied to revert back to the old behaviour of spawning new `tokio` tasks for each request:
```
--http-enable-beacon-processor <BOOLEAN>
The beacon processor is a scheduler which provides quality-of-service and DoS protection. When set to
"true", HTTP API requests will queued and scheduled alongside other tasks. When set to "false", HTTP API
responses will be executed immediately. [default: true]
```
## New CLI Flags
I added some other new CLI flags:
```
--beacon-processor-aggregate-batch-size <INTEGER>
Specifies the number of gossip aggregate attestations in a signature verification batch. Higher values may
reduce CPU usage in a healthy network while lower values may increase CPU usage in an unhealthy or hostile
network. [default: 64]
--beacon-processor-attestation-batch-size <INTEGER>
Specifies the number of gossip attestations in a signature verification batch. Higher values may reduce CPU
usage in a healthy network whilst lower values may increase CPU usage in an unhealthy or hostile network.
[default: 64]
--beacon-processor-max-workers <INTEGER>
Specifies the maximum concurrent tasks for the task scheduler. Increasing this value may increase resource
consumption. Reducing the value may result in decreased resource usage and diminished performance. The
default value is the number of logical CPU cores on the host.
--beacon-processor-reprocess-queue-len <INTEGER>
Specifies the length of the queue for messages requiring delayed processing. Higher values may prevent
messages from being dropped while lower values may help protect the node from becoming overwhelmed.
[default: 12288]
```
I needed to add the max-workers flag since the "simulator" flavor tests started failing with HTTP timeouts on the test assertions. I believe they were failing because the Github runners only have 2 cores and there just weren't enough workers available to process our requests in time. I added the other flags since they seem fun to fiddle with.
## Additional Info
I bumped the timeouts on the "simulator" flavor test from 4s to 8s. The prioritisation of consensus messages seems to be causing slower responses, I guess this is what we signed up for 🤷
The `validator/register` validator has some special handling because the relays have a bad habit of timing out on these calls. It seems like a waste of a `BeaconProcessor` worker to just wait for the builder API HTTP response, so we spawn a new `tokio` task to wait for a builder response.
I've added an optimisation for the `GET beacon/states/{state_id}/validators/{validator_id}` endpoint in [efbabe3](efbabe3252). That's the endpoint the VC uses to resolve pubkeys to validator indices, and it's the endpoint that was causing us grief. Perhaps I should move that into a new PR, not sure.
## Issue Addressed
Addresses #2557
## Proposed Changes
Adds the `lighthouse validator-manager` command, which provides:
- `lighthouse validator-manager create`
- Creates a `validators.json` file and a `deposits.json` (same format as https://github.com/ethereum/staking-deposit-cli)
- `lighthouse validator-manager import`
- Imports validators from a `validators.json` file to the VC via the HTTP API.
- `lighthouse validator-manager move`
- Moves validators from one VC to the other, utilizing only the VC API.
## Additional Info
In 98bcb947c I've reduced some VC `ERRO` and `CRIT` warnings to `WARN` or `DEBG` for the case where a pubkey is missing from the validator store. These were being triggered when we removed a validator but still had it in caches. It seems to me that `UnknownPubkey` will only happen in the case where we've removed a validator, so downgrading the logs is prudent. All the logs are `DEBG` apart from attestations and blocks which are `WARN`. I thought having *some* logging about this condition might help us down the track.
In 856cd7e37d I've made the VC delete the corresponding password file when it's deleting a keystore. This seemed like nice hygiene. Notably, it'll only delete that password file after it scans the validator definitions and finds that no other validator is also using that password file.
## Issue Addressed
NA
## Proposed Changes
We've been seeing a lot of [CI failures](https://github.com/sigp/lighthouse/actions/runs/5781296217/job/15666209142) with errors like this:
```
---- extra_interchange_tests::export_same_key_twice stdout ----
thread 'extra_interchange_tests::export_same_key_twice' panicked at 'called `Result::unwrap()` on an `Err` value: SQLError("Unable to open database: Error(None)")', validator_client/slashing_protection/src/extra_interchange_tests.rs:48:67
```
I'm assuming they're timeouts. I noticed that tests have a 0.1s timeout. Perhaps this just doesn't cut it when our new runners are overloaded.
## Additional Info
NA
**Motivation**
As clarified [on discord](https://discord.com/channels/605577013327167508/605577013331361793/1121246688183603240), sync committee contributions are not delayed if DP is enabled.
**Description**
This PR updates doppelganger note about sync committee contributions. Based on the current docs, a user might assume that DP is not working as expected.
## Issue Addressed
Addresses [#4401](https://github.com/sigp/lighthouse/issues/4401)
## Proposed Changes
Shift some constants into ```ChainSpec``` and remove the constant values from code space.
## Additional Info
I mostly used ```MainnetEthSpec::default_spec()``` for getting ```ChainSpec```. I wonder Did I make a mistake about that.
Co-authored-by: armaganyildirak <armaganyildirak@gmail.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
Co-authored-by: Age Manning <Age@AgeManning.com>
Co-authored-by: Diva M <divma@protonmail.com>
## Issue Addressed
Upgrade libp2p to v0.52
## Proposed Changes
- **Workflows**: remove installation of `protoc`
- **Book**: remove installation of `protoc`
- **`Dockerfile`s and `cross`**: remove custom base `Dockerfile` for cross since it's no longer needed. Remove `protoc` from remaining `Dockerfiles`s
- **Upgrade `discv5` to `v0.3.1`:** we have some cool stuff in there: no longer needs `protoc` and faster ip updates on cold start
- **Upgrade `prometheus` to `0.21.0`**, now it no longer needs encoding checks
- **things that look like refactors:** bunch of api types were renamed and need to be accessed in a different (clearer) way
- **Lighthouse network**
- connection limits is now a behaviour
- banned peers no longer exist on the swarm level, but at the behaviour level
- `connection_event_buffer_size` now is handled per connection with a buffer size of 4
- `mplex` is deprecated and was removed
- rpc handler now logs the peer to which it belongs
## Additional Info
Tried to keep as much behaviour unchanged as possible. However, there is a great deal of improvements we can do _after_ this upgrade:
- Smart connection limits: Connection limits have been checked only based on numbers, we can now use information about the incoming peer to decide if we want it
- More powerful peer management: Dial attempts from other behaviours can be rejected early
- Incoming connections can be rejected early
- Banning can be returned exclusively to the peer management: We should not get connections to banned peers anymore making use of this
- TCP Nat updates: We might be able to take advantage of confirmed external addresses to check out tcp ports/ips
Co-authored-by: Age Manning <Age@AgeManning.com>
Co-authored-by: Akihito Nakano <sora.akatsuki@gmail.com>
## Issue Addressed
Solves #4442
## Proposed Changes
EL clients log errors if we don't query this endpoint, but they are making releases that remove this error logging. After those are out we can stop calling it, after which point EL teams will remove the endpoint entirely.
Refer https://hackmd.io/@n0ble/deprecate-exchgTC
Some updates in the FAQ based on issues seen on Discord. Additionally, corrected the disk usage on the default SPRP as the previously provided value is not correct.
Co-authored-by: chonghe <44791194+chong-he@users.noreply.github.com>
Often when testing I have to create a hack which is annoying to maintain.
I think it might be handy to add a custom compile-time flag that developers can use if they want to test things locally without having to backfill a bunch of blocks.
There is probably an argument to have a feature called "backfill" which is enabled by default and can be disabled. I didn't go this route because I think it's counter-intuitive to have a feature that enables a core and necessary behaviour.
## Issue Addressed
The PR fixes a bug where the the ideal rewards for source and head were incorrectly set.
Output from testing a validator that performed optimally in a Phase 0 epoch , note the `source` and `target` under ideal rewards is incorrect (compared to the actual `total_rewards` below):
```json
{
"ideal_rewards": [
...
{
"effective_balance": "32000000000",
"head": "18771",
"target": "18770",
"source": "18729",
"inclusion_delay": "17083",
"inactivity": "0"
}
],
"total_rewards": [
{
"validator_index": "0",
"head": "18729",
"target": "18770",
"source": "18771",
"inclusion_delay": "17083",
"inactivity": "0"
}
]
```
## Proposed Changes
- Fix bad `state_root` reuse in `lcli transition-blocks` that resulted in invalid results at skipped slots.
- Modernise `lcli pretty-ssz` to include fork-generic decoders for `SignedBeaconBlock` and `BeaconState` which respect the `--network`/`--testnet-dir` flag.
## Additional Info
Breaking change: the underscore names like `signed_block_merge` are removed in favour of the fork-generic name `SignedBeaconBlock`, and fork-specific names which match the superstruct variants, e.g. `SignedBeaconBlockMerge`.
## Proposed Changes
Remove patch for `arbitrary` in favour of upstream, now that the `arithmetic_side_effects` lint no longer triggers in derive macro code.
## Additional Info
~~Blocked on Rust 1.71.0, to be released 13 July 23~~
## Issue Addressed
NA
## Proposed Changes
Carries on from #4115, with the following modifications:
1. Self-hosted runners are only enabled if `github.repository == sigp/lighthouse`.
- This allows forks to still have Github-hosted CI.
- This gives us a method to switch back to Github-runners if we have extended downtime on self-hosted.
1. Does not remove any existing dependency builds for Github-hosted runners (e.g., installing the latest Rust).
1. Adds the `WATCH_HOST` environment variable which defines where we expect to find the postgres db in the `watch` tests. This should be set to `host.docker.internal` for the tests to pass on self-hosted runners.
## Additional Info
NA
Co-authored-by: antondlr <anton@delaruelle.net>
## Issue Addressed
n/a Noticed this while working on something else
## Proposed Changes
- leverage the appropriate types to avoid a bunch of `unwrap` and errors
## Additional Info
n/a
## Issue Addressed
Speed up CI by installing foundry with Github action instead of building Anvil from source.
Building anvil from source on GItHub hosted runners currently takes about 10 mins. Using the `foundry-toolchain` action to install only takes about 2 seconds.
## Issue Addressed
N/A
## Proposed Changes
Add lints for rust 1.71
[3789134](3789134ae2) is probably the one that needs most attention as it changes beacon state code. I changed the `is_in_inactivity_leak ` function to return a `ArithError` as not all consumers of that function work well with a `BeaconState::Error`.
## Issue Addressed
This PR attempts to workaround the recent frequent eth1 simulator failures caused by missing eth logs from Anvil.
> FailedToInsertDeposit(NonConsecutive { log_index: 1, expected: 0 })
This usually occurs at the beginning of the tests, and it guarantees a timeout after a few hours if this log shows up, and this is currently causing our CIs to fail quite frequently.
Example failure here: https://github.com/sigp/lighthouse/actions/runs/5525760195/jobs/10079736914
## Proposed Changes
The quick fix applied here adds a timeout to node startup and restarts the node again.
- Add a 60 seconds timeout to beacon node startup in eth1 simulator tests. It takes ~10 seconds on my machine, but could take longer on CI runners.
- Wrap the startup code in a retry function, that allows for 3 retries before returning an error.
## Additional Info
We should probably raise an issue under the Anvil GitHub repo there so this can be further investigated.
## Issue Addressed
Addresses an issue where CI could fail due to an nonexisting file error:
```
Run ./clean.sh
rm: cannot remove '/home/runner/.lighthouse/local-testnet/geth_datadir4/geth/fastcache.tmp.1549331618': No such file or directory
Error: Process completed with exit code 1.
```
This seems to happen quite frequently now, I'm not sure exactly why but perhaps worth trying suppressing the prompt?
https://github.com/sigp/lighthouse/actions/runs/5455027574/jobs/9925916159?pr=4463
## Proposed Changes
Replace `wget` in the EF-tests makefile with `curl`.
On macOS `curl` is pre-installed, and I found myself making this change to avoid installing `wget`.
The `-L` flag is used to follow redirects which is useful if a repo gets renamed, and more similar to `wget`'s default behaviour.
## Issue Addressed
Fixes occasional compilation errors with mev-rs (see #4456).
## Proposed Changes
- Update `mev-rs` to the latest version, which allows us to remove hacky `[patch]` sections
- Update the `axum` version used in `watch` so LH only uses a single version
## Issue Addressed
#4488
## Proposed Changes
- Remove all instances of the `required` modifier where we have a default value specified for a subcommand
## Additional Info
N/A
## Issue Addressed
When trying to run `eth1-sim` locally, the simulator doesn't start for me, and panicked due to duplicate arg names for `proposer-nodes` (using same arg names as `nodes`). Not sure why this isn't failing on CI but failing on mine 🤔
```
thread 'main' panicked at 'Argument short must be unique
thread 'main' panicked at 'Argument long must be unique
```
## Issue Addressed
Fix an issue observed by `@zlan` on Discord where Lighthouse would sometimes return this error when looking up states via the API:
> {"code":500,"message":"UNHANDLED_ERROR: ForkChoiceError(MissingProtoArrayBlock(0xc9cf1495421b6ef3215d82253b388d77321176a1dcef0db0e71a0cd0ffc8cdb7))","stacktraces":[]}
## Proposed Changes
The error stems from a faulty assumption in the HTTP API logic: that any state in the hot database must have its block in fork choice. This isn't true because the state's hot database may update much less frequently than the fork choice store, e.g. if reconstructing states (where freezer migration pauses), or if the freezer migration runs slowly. There could also be a race between loading the hot state and checking fork choice, e.g. even if the finalization migration of DB+fork choice were atomic, the update could happen between the 1st and 2nd calls.
To address this I've changed the HTTP API logic to use the finalized block's execution status as a fallback where it is safe to do so. In the case where a block is non-canonical and prior to finalization (permanently orphaned) we default `execution_optimistic` to `true`.
## Additional Info
I've also added a new CLI flag to reduce the frequency of the finalization migration as this is useful for several purposes:
- Spacing out database writes (less frequent, larger batches)
- Keeping a limited chain history with high availability, e.g. the last month in the hot database.
This new flag made it _substantially_ easier to test this change. It was extracted from `tree-states` (where it's called `--db-migration-period`), which is why this PR also carries the `tree-states` label.
## Issue Addressed
#4494
## Proposed Changes
- Remove explicit re-exports of various types to appease the new compiler lint
## Additional Info
It seems `warn(hidden_glob_reexports)` is the main culprit.
## Proposed Changes
* Add `lcli state-root` command for computing the hash tree root of a `BeaconState`.
* Add a `--network` flag which can be used instead of `--testnet-dir` to set the network, e.g. Mainnet, Goerli, Gnosis.
* Use the new network flag in `transition-blocks`, `skip-slots`, and `block-root`, which previously only supported mainnet.
* **BREAKING CHANGE** Remove the default value of `~/.lighthouse/testnet` from `--testnet-dir`. This may have made sense in previous versions where `lcli` was more testnet focussed, but IMO it is an unnecessary complication and foot-gun today.
*Replaces #4434. It is identical, but this PR has a smaller diff due to a curated commit history.*
## Issue Addressed
NA
## Proposed Changes
This PR moves the scheduling logic for the `BeaconProcessor` into a new crate in `beacon_node/beacon_processor`. Previously it existed in the `beacon_node/network` crate.
This addresses a circular-dependency problem where it's not possible to use the `BeaconProcessor` from the `beacon_chain` crate. The `network` crate depends on the `beacon_chain` crate (`network -> beacon_chain`), but importing the `BeaconProcessor` into the `beacon_chain` crate would create a circular dependancy of `beacon_chain -> network`.
The `BeaconProcessor` was designed to provide queuing and prioritized scheduling for messages from the network. It has proven to be quite valuable and I believe we'd make Lighthouse more stable and effective by using it elsewhere. In particular, I think we should use the `BeaconProcessor` for:
1. HTTP API requests.
1. Scheduled tasks in the `BeaconChain` (e.g., state advance).
Using the `BeaconProcessor` for these tasks would help prevent the BN from becoming overwhelmed and would also help it to prioritize operations (e.g., choosing to process blocks from gossip before responding to low-priority HTTP API requests).
## Additional Info
This PR is intended to have zero impact on runtime behaviour. It aims to simply separate the *scheduling* code (i.e., the `BeaconProcessor`) from the *business logic* in the `network` crate (i.e., the `Worker` impls). Future PRs (see #4462) can build upon these works to actually use the `BeaconProcessor` for more operations.
I've gone to some effort to use `git mv` to make the diff look more like "file was moved and modified" rather than "file was deleted and a new one added". This should reduce review burden and help maintain commit attribution.
## Issue Addressed
[Users on Twitter](https://twitter.com/ashekhirin/status/1676334843192397824) are getting checkpoint sync URL timeouts with the default of 60s, so this PR increases the default timeout to 3 minutes.
I've also added a short section to the book about adjusting the timeout with `--checkpoint-sync-url-timeout`.
## Issue Addressed
#4331
## Proposed Changes
- Use comparison rather than strict equality between the earliest epoch we know about and the backfill target (which will be the most recent WSP by default or genesis)
- Add helper function `BackFillSync<T>::would_complete` to achieve this in one location
## Additional Info
- There's an ad hoc test for this in #4461
Co-authored-by: Age Manning <Age@AgeManning.com>
We now officially have ipv6 support. The mainnet bootnodes have been updated to support ipv6. This PR updates lighthouse's internal bootnodes for mainnet to avoid fetching them on initial load.
## Issue Addressed
#4118
## Proposed Changes
This PR introduces a "progressive balances" cache on the `BeaconState`, which keeps track of the accumulated target attestation balance for the current & previous epochs. The cached values are utilised by fork choice to calculate unrealized justification and finalization (instead of converting epoch participation arrays to balances for each block we receive).
This optimization will be rolled out gradually to allow for more testing. A new `--progressive-balances disabled|checked|strict|fast` flag is introduced to support this:
- `checked`: enabled with checks against participation cache, and falls back to the existing epoch processing calculation if there is a total target attester balance mismatch. There is no performance gain from this as the participation cache still needs to be computed. **This is the default mode for now.**
- `strict`: enabled with checks against participation cache, returns error if there is a mismatch. **Used for testing only**.
- `fast`: enabled with no comparative checks and without computing the participation cache. This mode gives us the performance gains from the optimization. This is still experimental and not currently recommended for production usage, but will become the default mode in a future release.
- `disabled`: disable the usage of progressive cache, and use the existing method for FFG progression calculation. This mode may be useful if we find a bug and want to stop the frequent error logs.
### Tasks
- [x] Initial cache implementation in `BeaconState`
- [x] Perform checks in fork choice to compare the progressive balances cache against results from `ParticipationCache`
- [x] Add CLI flag, and disable the optimization by default
- [x] Testing on Goerli & Benchmarking
- [x] Move caching logic from state processing to the `ProgressiveBalancesCache` (see [this comment](https://github.com/sigp/lighthouse/pull/4362#discussion_r1230877001))
- [x] Add attesting balance metrics
Co-authored-by: Jimmy Chen <jimmy@sigmaprime.io>
## Issue Addressed
[#4292](https://github.com/sigp/lighthouse/issues/4292)
## Proposed Changes
Updated the node health endpoint
will return a 200 status code if `!syncing && !el_offline && !optimistic`
wil return a 206 if `(syncing || optimistic) && !el_offline`
will return a 503 if `el_offline`
## Additional Info
## Issue Addressed
[#4259](https://github.com/sigp/lighthouse/issues/4259)
## Proposed Changes
debounce spammy `Unable to send message to the beacon processor` log messages
## Additional Info
We could potentially debounce other logs that have the potential to be "spammy".
After some feedback we decided to additionally add the following change:
create a newtype wrapper around `mpsc::Sender<BeaconWorkEvent<T>>`. When there is an error on the try_send method on the wrapper, we increase a counter metric with one label per work type.
## Issue Addressed
- #4293
- #4264
## Proposed Changes
*Changes largely follow those suggested in the main issue*.
- Add new routes to HTTP API
- `post_beacon_blocks_v2`
- `post_blinded_beacon_blocks_v2`
- Add new routes to `BeaconNodeHttpClient`
- `post_beacon_blocks_v2`
- `post_blinded_beacon_blocks_v2`
- Define new Eth2 common types
- `BroadcastValidation`, enum representing the level of validation to apply to blocks prior to broadcast
- `BroadcastValidationQuery`, the corresponding HTTP query string type for the above type
- ~~Define `_checked` variants of both `publish_block` and `publish_blinded_block` that enforce a validation level at a type level~~
- Add interactive tests to the `bn_http_api_tests` test target covering each validation level (to their own test module, `broadcast_validation_tests`)
- `beacon/blocks`
- `broadcast_validation=gossip`
- Invalid (400)
- Full Pass (200)
- Partial Pass (202)
- `broadcast_validation=consensus`
- Invalid (400)
- Only gossip (400)
- Only consensus pass (i.e., equivocates) (200)
- Full pass (200)
- `broadcast_validation=consensus_and_equivocation`
- Invalid (400)
- Invalid due to early equivocation (400)
- Only gossip (400)
- Only consensus (400)
- Pass (200)
- `beacon/blinded_blocks`
- `broadcast_validation=gossip`
- Invalid (400)
- Full Pass (200)
- Partial Pass (202)
- `broadcast_validation=consensus`
- Invalid (400)
- Only gossip (400)
- ~~Only consensus pass (i.e., equivocates) (200)~~
- Full pass (200)
- `broadcast_validation=consensus_and_equivocation`
- Invalid (400)
- Invalid due to early equivocation (400)
- Only gossip (400)
- Only consensus (400)
- Pass (200)
- Add a new trait, `IntoGossipVerifiedBlock`, which allows type-level guarantees to be made as to gossip validity
- Modify the structure of the `ObservedBlockProducers` cache from a `(slot, validator_index)` mapping to a `((slot, validator_index), block_root)` mapping
- Modify `ObservedBlockProducers::proposer_has_been_observed` to return a `SeenBlock` rather than a boolean on success
- Punish gossip peer (low) for submitting equivocating blocks
- Rename `BlockError::SlashablePublish` to `BlockError::SlashableProposal`
## Additional Info
This PR contains changes that directly modify how blocks are verified within the client. For more context, consult [comments in-thread](https://github.com/sigp/lighthouse/pull/4316#discussion_r1234724202).
Co-authored-by: Michael Sproul <michael@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
Implements the `PrettyReqwestError` to wrap a `reqwest::Error` and give nicer `Debug` formatting. It also wraps the `Url` component in a `SensitiveUrl` to avoid leaking sensitive info in logs.
### Before
```
Reqwest(reqwest::Error { kind: Request, url: Url { scheme: "http", cannot_be_a_base: false, username: "", password: None, host: Some(Domain("localhost")), port: Some(9999), path: "/eth/v1/node/version", query: None, fragment: None }, source: hyper::Error(Connect, ConnectError("tcp connect error", Os { code: 61, kind: ConnectionRefused, message: "Connection refused" })) })
```
### After
```
HttpClient(url: http://localhost:9999/, kind: request, detail: error trying to connect: tcp connect error: Connection refused (os error 61))
```
## Additional Info
I've also renamed the `Reqwest` error enum variants to `HttpClient`, to give people a better chance at knowing what's going on. Reqwest is pretty odd and looks like a typo.
I've implemented it in the `eth2` and `execution_layer` crates. This should affect most logs in the VC and EE-related ones in the BN.
I think the last crate that could benefit from the is the `beacon_node/eth1` crate. I haven't updated it in this PR since its error type is not so amenable to it (everything goes into a `String`). I don't have a whole lot of time to jig around with that at the moment and I feel that this PR as it stands is a significant enough improvement to merge on its own. Leaving it as-is is fine for the time being and we can always come back for it later (or implement in-protocol deposits!).
## Issue Addressed
Resolves#3238
## Proposed Changes
Please list or describe the changes introduced by this PR.
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
## Issue Addressed
This PR adds a new `lint-fix` task to automatically fix simple Clippy warnings using `cargo clippy --fix`.
Usage:
```
make lint-fix
```
## Issue Addressed
#4386
## Proposed Changes
The original proposal described in the issue adds a new endpoint to support updating validator graffiti, but I realized we already have an endpoint that we use for updating various validator fields in memory and in the validator definitions file, so I think that would be the best place to add this to.
### API endpoint
`PATCH lighthouse/validators/{validator_pubkey}`
This endpoint updates the graffiti in both the [ validator definition file](https://lighthouse-book.sigmaprime.io/graffiti.html#2-setting-the-graffiti-in-the-validator_definitionsyml) and the in memory `InitializedValidators`. In the next block proposal, the new graffiti will be used.
Note that the [`--graffiti-file`](https://lighthouse-book.sigmaprime.io/graffiti.html#1-using-the---graffiti-file-flag-on-the-validator-client) flag has a priority over the validator definitions file, so if the caller attempts to update the graffiti while the `--graffiti-file` flag is present, the endpoint will return an error (Bad request 400).
## Tasks
- [x] Add graffiti update support to `PATCH lighthouse/validators/{validator_pubkey}`
- [x] Return error if user tries to update graffiti while the `--graffiti-flag` is set
- [x] Update Lighthouse book
