## Issue Addressed
Resolves#3516
## Proposed Changes
Adds a beacon fallback function for running a beacon node http query on all available fallbacks instead of returning on a first successful result. Uses the new `run_on_all` method for attestation and sync committee subscriptions.
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
## Issue Addressed
fixes lints from the last rust release
## Proposed Changes
Fix the lints, most of the lints by `clippy::question-mark` are false positives in the form of https://github.com/rust-lang/rust-clippy/issues/9518 so it's allowed for now
## Additional Info
## Issue Addressed
Resolves: #3550
Remove the `--strict-fee-recipient` flag. It will cause missed proposals prior to the bellatrix transition.
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
Closes#3514
## Proposed Changes
- Change default monitoring endpoint frequency to 120 seconds to fit with 30k requests/month limit.
- Allow configuration of the monitoring endpoint frequency using `--monitoring-endpoint-frequency N` where `N` is a value in seconds.
## Issue Addressed
[Have --checkpoint-sync-url timeout](https://github.com/sigp/lighthouse/issues/3478)
## Proposed Changes
I added a parameter for `get_bytes_opt_accept_header<U: IntoUrl>` which accept a timeout duration, and modified the body of `get_beacon_blocks_ssz` and `get_debug_beacon_states_ssz` to pass corresponding timeout durations.
## Issue Addressed
Resolves#3524
## Proposed Changes
Log fee recipient in the `Validator exists in beacon chain` log. Logging in the BN already happens here 18c61a5e8b/beacon_node/beacon_chain/src/beacon_chain.rs (L3858-L3865)
I also think it's good practice to encourage users to set the fee recipient in the VC rather than the BN because of issues mentioned here https://github.com/sigp/lighthouse/issues/3432
Some example logs from prater:
```
Aug 30 03:47:09.922 INFO Validator exists in beacon chain fee_recipient: 0xab97_ad88, validator_index: 213615, pubkey: 0xb542b69ba14ddbaf717ca1762ece63a4804c08d38a1aadf156ae718d1545942e86763a1604f5065d4faa550b7259d651, service: duties
Aug 30 03:48:05.505 INFO Validator exists in beacon chain fee_recipient: Fee recipient for validator not set in validator_definitions.yml or provided with the `--suggested-fee-recipient flag`, validator_index: 210710, pubkey: 0xad5d67cc7f990590c7b3fa41d593c4cf12d9ead894be2311fbb3e5c733d8c1b909e9d47af60ea3480fb6b37946c35390, service: duties
```
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
Relates to https://github.com/sigp/lighthouse/issues/3416
## Proposed Changes
- Add an `OfflineOnFailure` enum to the `first_success` method for querying beacon nodes so that a val registration request failure from the BN -> builder does not result in the BN being marked offline. This seems important because these failures could be coming directly from a connected relay and actually have no bearing on BN health. Other messages that are sent to a relay have a local fallback so shouldn't result in errors
- Downgrade the following log to a `WARN`
```
ERRO Unable to publish validator registrations to the builder network, error: All endpoints failed https://BN_B => RequestFailed(ServerMessage(ErrorMessage { code: 500, message: "UNHANDLED_ERROR: BuilderMissing", stacktraces: [] })), https://XXXX/ => Unavailable(Offline), [omitted]
```
## Additional Info
I think this change at least improves the UX of having a VC connected to some builder and some non-builder beacon nodes. I think we need to balance potentially alerting users that there is a BN <> VC misconfiguration and also allowing this type of fallback to work.
If we want to fully support this type of configuration we may want to consider adding a flag `--builder-beacon-nodes` and track whether a VC should be making builder queries on a per-beacon node basis. But I think the changes in this PR are independent of that type of extension.
PS: Sorry for the big diff here, it's mostly formatting changes after I added a new arg to a bunch of methods calls.
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
Indicate that local keystores are `readonly: Some(false)` rather than `None` via the `/eth/v1/keystores` method on the VC API.
I'll mark this as backwards-incompat so we remember to mention it in the release notes. There aren't any type-level incompatibilities here, just a change in how Lighthouse responds to responses.
## Additional Info
- Blocked on #3464
## Proposed Changes
Update the merge migration docs to encourage updating mainnet configs _now_!
The docs are also updated to recommend _against_ `--suggested-fee-recipient` on the beacon node (https://github.com/sigp/lighthouse/issues/3432).
Additionally the `--help` for the CLI is updated to match with a few small semantic changes:
- `--execution-jwt` is no longer allowed without `--execution-endpoint`. We've ended up without a default for `--execution-endpoint`, so I think that's fine.
- The flags related to the JWT are only allowed if `--execution-jwt` is provided.
## Issue Addressed
Resolves#3388Resolves#2638
## Proposed Changes
- Return the `BellatrixPreset` on `/eth/v1/config/spec` by default.
- Allow users to opt out of this by providing `--http-spec-fork=altair` (unless there's a Bellatrix fork epoch set).
- Add the Altair constants from #2638 and make serving the constants non-optional (the `http-disable-legacy-spec` flag is deprecated).
- Modify the VC to only read the `Config` and not to log extra fields. This prevents it from having to muck around parsing the `ConfigAndPreset` fields it doesn't need.
## Additional Info
This change is backwards-compatible for the VC and the BN, but is marked as a breaking change for the removal of `--http-disable-legacy-spec`.
I tried making `Config` a `superstruct` too, but getting the automatic decoding to work was a huge pain and was going to require a lot of hacks, so I gave up in favour of keeping the default-based approach we have now.
## Issue Addressed
Fixes#2967
## Proposed Changes
Collect validator indices alongside attestations when creating signed
attestations (and aggregates) for inclusion in the logs.
## Additional Info
This is my first time looking at Lighthouse source code and using Rust, so newbie feedback appreciated!
## Issue Addressed
https://github.com/sigp/lighthouse/issues/3091
Extends https://github.com/sigp/lighthouse/pull/3062, adding pre-bellatrix block support on blinded endpoints and allowing the normal proposal flow (local payload construction) on blinded endpoints. This resulted in better fallback logic because the VC will not have to switch endpoints on failure in the BN <> Builder API, the BN can just fallback immediately and without repeating block processing that it shouldn't need to. We can also keep VC fallback from the VC<>BN API's blinded endpoint to full endpoint.
## Proposed Changes
- Pre-bellatrix blocks on blinded endpoints
- Add a new `PayloadCache` to the execution layer
- Better fallback-from-builder logic
## Todos
- [x] Remove VC transition logic
- [x] Add logic to only enable builder flow after Merge transition finalization
- [x] Tests
- [x] Fix metrics
- [x] Rustdocs
Co-authored-by: Mac L <mjladson@pm.me>
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
Resolves#3151
## Proposed Changes
When fetching duties for sync committee contributions, check the value of `execution_optimistic` of the head block from the BN and refuse to sign any sync committee messages `if execution_optimistic == true`.
## Additional Info
- Is backwards compatible with older BNs
- Finding a way to add test coverage for this would be prudent. Open to suggestions.
## Issue Addressed
Resolves#3267Resolves#3156
## Proposed Changes
- Move the log for fee recipient checks from proposer cache insertion into block proposal so we are directly checking what we get from the EE
- Only log when there is a discrepancy with the local EE, not when using the builder API. In the `builder-api` branch there is an `info` log when there is a discrepancy, I think it is more likely there will be a difference in fee recipient with the builder api because proposer payments might be made via a transaction in the block. Not really sure what patterns will become commong.
- Upgrade the log from a `warn` to an `error` - not actually sure which we want, but I think this is worth an error because the local EE with default transaction ordering I think should pretty much always use the provided fee recipient
- add a `strict-fee-recipient` flag to the VC so we only sign blocks with matching fee recipients. Falls back from the builder API to the local API if there is a discrepancy .
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
#3302
## Proposed Changes
Move the `reqwest::Client` from being initialized per-validator, to being initialized per distinct Web3Signer.
This is done by placing the `Client` into a `HashMap` keyed by the definition of the Web3Signer as specified by the `ValidatorDefintion`. This will allow multiple Web3Signers to be used with a single VC and also maintains backwards compatibility.
## Additional Info
This was done to reduce the memory used by the VC when connecting to a Web3Signer.
I set up a local testnet using [a custom script](https://github.com/macladson/lighthouse/tree/web3signer-local-test/scripts/local_testnet_web3signer) and ran a VC with 200 validator keys:
VC with Web3Signer:
- `unstable`: ~200MB
- With fix: ~50MB
VC with Local Signer:
- `unstable`: ~35MB
- With fix: ~35MB
> I'm seeing some fragmentation with the VC using the Web3Signer, but not when using a local signer (this is most likely due to making lots of http requests and dealing with lots of JSON objects). I tested the above using `MALLOC_ARENA_MAX=1` to try to reduce the fragmentation. Without it, the values are around +50MB for both `unstable` and the fix.
## Issue Addressed
Web3signer validators can't produce post-Bellatrix blocks.
## Proposed Changes
Add support for Bellatrix to web3signer validators.
## Additional Info
I am running validators with this code on Ropsten, but it may be a while for them to get a proposal.
## Issue Addressed
Resolves#3276.
## Proposed Changes
Add a timeout for the sync committee contributions at 1/4 the slot length such that we may be able to try backup beacon nodes in the case of contribution post failure.
## Additional Info
1/4 slot length seemed standard for the timeouts, but may want to decrease this to 1/2.
I did not find any timeout related / sync committee related tests, so there are no tests. Happy to write some with a bit of guidance.
## Issue Addressed
* #3173
## Proposed Changes
Moved all `fee_recipient_file` related logic inside the `ValidatorStore` as it makes more sense to have this all together there. I tested this with the validators I have on `mainnet-shadow-fork-5` and everything appeared to work well. Only technicality is that I can't get the method to return `401` when the authorization header is not specified (it returns `400` instead). Fixing this is probably quite difficult given that none of `warp`'s rejections have code `401`.. I don't really think this matters too much though as long as it fails.
## Issue Addressed
Lays the groundwork for builder API changes by implementing the beacon-API's new `register_validator` endpoint
## Proposed Changes
- Add a routine in the VC that runs on startup (re-try until success), once per epoch or whenever `suggested_fee_recipient` is updated, signing `ValidatorRegistrationData` and sending it to the BN.
- TODO: `gas_limit` config options https://github.com/ethereum/builder-specs/issues/17
- BN only sends VC registration data to builders on demand, but VC registration data *does update* the BN's prepare proposer cache and send an updated fcU to a local EE. This is necessary for fee recipient consistency between the blinded and full block flow in the event of fallback. Having the BN only send registration data to builders on demand gives feedback directly to the VC about relay status. Also, since the BN has no ability to sign these messages anyways (so couldn't refresh them if it wanted), and validator registration is independent of the BN head, I think this approach makes sense.
- Adds upcoming consensus spec changes for this PR https://github.com/ethereum/consensus-specs/pull/2884
- I initially applied the bit mask based on a configured application domain.. but I ended up just hard coding it here instead because that's how it's spec'd in the builder repo.
- Should application mask appear in the api?
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
Following up from https://github.com/sigp/lighthouse/pull/3223#issuecomment-1158718102, it has been observed that the validator client uses vastly more memory in some compilation configurations than others. Compiling with Cross and then putting the binary into an Ubuntu 22.04 image seems to use 3x more memory than compiling with Cargo directly on Debian bullseye.
## Proposed Changes
Enable malloc metrics for the validator client. This will hopefully allow us to see the difference between the two compilation configs and compare heap fragmentation. This PR doesn't enable malloc tuning for the VC because it was found to perform significantly worse. The `--disable-malloc-tuning` flag is repurposed to just disable the metrics.
## Issue Addressed
#3154
## Proposed Changes
Add three new metrics for the VC:
1. `vc_beacon_nodes_synced_count`
2. `vc_beacon_nodes_available_count`
3. `vc_beacon_nodes_total_count`
Their values mirror the values present in the following log line:
```
Apr 08 17:25:17.000 INFO Connected to beacon node(s) synced: 4, available: 4, total: 4, service: notifier
```
## Issue Addressed
This fixes the low-hanging Clippy lints introduced in Rust 1.61 (due any hour now). It _ignores_ one lint, because fixing it requires a structural refactor of the validator client that needs to be done delicately. I've started on that refactor and will create another PR that can be reviewed in more depth in the coming days. I think we should merge this PR in the meantime to unblock CI.
## Issue Addressed
Web3Signer validators do not support client authentication. This means the `--tls-known-clients-file` option on Web3Signer can't be used with Lighthouse.
## Proposed Changes
Add two new fields to Web3Signer validators, `client_identity_path` and `client_identity_password`, which specify the path and password for a PKCS12 file containing a certificate and private key. If `client_identity_path` is present, use the certificate for SSL client authentication.
## Additional Info
I am successfully validating on Prater using client authentication with Web3Signer and client authentication.
## Issue Addressed
#3141
## Proposed Changes
Changes the algorithm for proposing blocks from
```
For each BN (first success):
- Produce a block
- Sign the block and store its root in the slashing protection DB
- Publish the block
```
to
```
For each BN (first success):
- Produce a block
Sign the block and store its root in the slashing protection DB
For each BN (first success):
- Publish the block
```
Separating the producing from the publishing makes sure that we only add a signed block once to the slashing DB.
# Description
Since the `TaskExecutor` currently requires a `Weak<Runtime>`, it's impossible to use it in an async test where the `Runtime` is created outside our scope. Whilst we *could* create a new `Runtime` instance inside the async test, dropping that `Runtime` would cause a panic (you can't drop a `Runtime` in an async context).
To address this issue, this PR creates the `enum Handle`, which supports either:
- A `Weak<Runtime>` (for use in our production code)
- A `Handle` to a runtime (for use in testing)
In theory, there should be no change to the behaviour of our production code (beyond some slightly different descriptions in HTTP 500 errors), or even our tests. If there is no change, you might ask *"why bother?"*. There are two PRs (#3070 and #3175) that are waiting on these fixes to introduce some new tests. Since we've added the EL to the `BeaconChain` (for the merge), we are now doing more async stuff in tests.
I've also added a `RuntimeExecutor` to the `BeaconChainTestHarness`. Whilst that's not immediately useful, it will become useful in the near future with all the new async testing.
Code simplifications using `Option`/`Result` combinators to make pattern-matches a tad simpler.
Opinions on these loosely held, happy to adjust in review.
Tool-aided by [comby-rust](https://github.com/huitseeker/comby-rust).
## Issue Addressed
#3068
## Proposed Changes
Adds support for remote key API.
## Additional Info
Needed to add `is_local_keystore` argument to `delete_definition_and_keystore` to know if we want to delete local or remote key. Previously this wasn't necessary because remotekeys(web3signers) could be deleted.
## Issue Addressed
MEV boost compatibility
## Proposed Changes
See #2987
## Additional Info
This is blocked on the stabilization of a couple specs, [here](https://github.com/ethereum/beacon-APIs/pull/194) and [here](https://github.com/flashbots/mev-boost/pull/20).
Additional TODO's and outstanding questions
- [ ] MEV boost JWT Auth
- [ ] Will `builder_proposeBlindedBlock` return the revealed payload for the BN to propogate
- [ ] Should we remove `private-tx-proposals` flag and communicate BN <> VC with blinded blocks by default once these endpoints enter the beacon-API's repo? This simplifies merge transition logic.
Co-authored-by: realbigsean <seananderson33@gmail.com>
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
#3103
## Proposed Changes
Parse `http-address` and `metrics-address` as `IpAddr` for both the beacon node and validator client to support IPv6 addresses.
Also adjusts parsing of CORS origins to allow for IPv6 addresses.
## Usage
You can now set `http-address` and/or `metrics-address` flags to IPv6 addresses.
For example, the following:
`lighthouse bn --http --http-address :: --metrics --metrics-address ::1`
will expose the beacon node HTTP server on `[::]` (equivalent of `0.0.0.0` in IPv4) and the metrics HTTP server on `localhost` (the equivalent of `127.0.0.1` in IPv4)
The beacon node API can then be accessed by:
`curl "http://[server-ipv6-address]:5052/eth/v1/some_endpoint"`
And the metrics server api can be accessed by:
`curl "http://localhost:5054/metrics"` or by `curl "http://[::1]:5054/metrics"`
## Additional Info
On most Linux distributions the `v6only` flag is set to `false` by default (see the section for the `IPV6_V6ONLY` flag in https://www.man7.org/linux/man-pages/man7/ipv6.7.html) which means IPv4 connections will continue to function on a IPv6 address (providing it is appropriately mapped). This means that even if the Lighthouse API is running on `::` it is also possible to accept IPv4 connections.
However on Windows, this is not the case. The `v6only` flag is set to `true` so binding to `::` will only allow IPv6 connections.
## Issue Addressed
Presently if the VC is configured with a fee recipient it will error out when sending fee-recipient preparations to a beacon node that doesn't yet support the API:
```
Mar 08 22:23:36.236 ERRO Unable to publish proposer preparation error: All endpoints failed https://eth2-beacon-prater.infura.io/ => RequestFailed(StatusCode(404)), service: preparation
```
This doesn't affect other VC duties, but could be a source of anxiety for users trying to do the right thing and configure their fee recipients in advance.
## Proposed Changes
Change the preparation service to only send preparations if the current slot is later than 2 epochs before the Bellatrix hard fork epoch.
## Additional Info
I've tagged this v2.1.4 as I think it's a small change that's worth having for the next release
## Proposed Changes
Lots of lint updates related to `flat_map`, `unwrap_or_else` and string patterns. I did a little more creative refactoring in the op pool, but otherwise followed Clippy's suggestions.
## Additional Info
We need this PR to unblock CI.
## Issue Addressed
#3020
## Proposed Changes
- Alias the `validators-dir` arg to `validator-dir` in the `validator_client` subcommand.
- Alias the `validator-dir` arg to `validators-dir` in the `account_manager validator` subcommand.
- Add test for the validator_client alias.
## Issue Addressed
Addresses https://github.com/sigp/lighthouse/issues/2926
## Proposed Changes
Appropriated from https://github.com/sigp/lighthouse/issues/2926#issuecomment-1039676768:
When a node returns *any* error we call [`CandidateBeaconNode::set_offline`](c3a793fd73/validator_client/src/beacon_node_fallback.rs (L424)) which sets it's `status` to `CandidateError::Offline`. That node will then be ignored until the routine [`fallback_updater_service`](c3a793fd73/validator_client/src/beacon_node_fallback.rs (L44)) manages to reconnect to it.
However, I believe there was an issue in the [`CanidateBeaconNode::refesh_status`](c3a793fd73/validator_client/src/beacon_node_fallback.rs (L157-L178)) method, which is used by the updater service to see if the node has come good again. It was holding a [write lock on the `status` field](c3a793fd73/validator_client/src/beacon_node_fallback.rs (L165)) whilst it polled the node status. This means a long timeout would hog the write lock and starve other processes.
When a VC is trying to access a beacon node for whatever purpose (getting duties, posting blocks, etc), it performs [three passes](c3a793fd73/validator_client/src/beacon_node_fallback.rs (L432-L482)) through the lists of nodes, trying to run some generic `function` (closure, lambda, etc) on each node:
- 1st pass: only try running `function` on all nodes which are both synced and online.
- 2nd pass: try running `function` on all nodes that are online, but not necessarily synced.
- 3rd pass: for each offline node, try refreshing its status and then running `function` on it.
So, it turns out that if the `CanidateBeaconNode::refesh_status` function from the routine update service is hogging the write-lock, the 1st pass gets blocked whilst trying to read the status of the first node. So, nodes that should be left until the 3rd pass are blocking the process of the 1st and 2nd passes, hence the behaviour described in #2926.
## Additional Info
NA
## Issue Addressed
#2953
## Proposed Changes
Adds empty local validator check.
## Additional Info
Two other options:
- add check inside `local_index` collection. Instead of after collection.
- Move `local_index` collection to the beginning of the `poll_sync_committee_duties` function and combine sync committee with altair fork check.
## Issue Addressed
#2883
## Proposed Changes
* Added `suggested-fee-recipient` & `suggested-fee-recipient-file` flags to validator client (similar to graffiti / graffiti-file implementation).
* Added proposer preparation service to VC, which sends the fee-recipient of all known validators to the BN via [/eth/v1/validator/prepare_beacon_proposer](https://github.com/ethereum/beacon-APIs/pull/178) api once per slot
* Added [/eth/v1/validator/prepare_beacon_proposer](https://github.com/ethereum/beacon-APIs/pull/178) api endpoint and preparation data caching
* Added cleanup routine to remove cached proposer preparations when not updated for 2 epochs
## Additional Info
Changed the Implementation following the discussion in #2883.
Co-authored-by: pk910 <philipp@pk910.de>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
Co-authored-by: Philipp K <philipp@pk910.de>
## Issue Addressed
Implements the standard key manager API from https://ethereum.github.io/keymanager-APIs/, formerly https://github.com/ethereum/beacon-APIs/pull/151
Related to https://github.com/sigp/lighthouse/issues/2557
## Proposed Changes
- [x] Add all of the new endpoints from the standard API: GET, POST and DELETE.
- [x] Add a `validators.enabled` column to the slashing protection database to support atomic disable + export.
- [x] Add tests for all the common sequential accesses of the API
- [x] Add tests for interactions with remote signer validators
- [x] Add end-to-end tests for migration of validators from one VC to another
- [x] Implement the authentication scheme from the standard (token bearer auth)
## Additional Info
The `enabled` column in the validators SQL database is necessary to prevent a race condition when exporting slashing protection data. Without the slashing protection database having a way of knowing that a key has been disabled, a concurrent request to sign a message could insert a new record into the database. The `delete_concurrent_with_signing` test exercises this code path, and was indeed failing before the `enabled` column was added.
The validator client authentication has been modified from basic auth to bearer auth, with basic auth preserved for backwards compatibility.
## Proposed Changes
Remove the check for exact equality on the beacon node spec when polling `/config/spec` from the VC. This check was always overzealous, and mostly served to check that the BN was configured for upcoming forks. I've replaced it by explicit checks of the `altair_fork_epoch` and `bellatrix_fork_epoch` instead.
## Additional Info
We should come back to this and clean it up so that we can retain compatibility while removing the field `default`s we installed.
## Issue Addressed
New rust lints
## Proposed Changes
- Boxing some enum variants
- removing some unused fields (is the validator lockfile unused? seemed so to me)
## Additional Info
- some error fields were marked as dead code but are logged out in areas
- left some dead fields in our ef test code because I assume they are useful for debugging?
Co-authored-by: realbigsean <seananderson33@gmail.com>
## Issue Addressed
Resolves#2612
## Proposed Changes
Implements both the checks mentioned in the original issue.
1. Verifies the `randao_reveal` in the beacon node
2. Cross checks the proposer index after getting back the block from the beacon node.
## Additional info
The block production time increases by ~10x because of the signature verification on the beacon node (based on the `beacon_block_production_process_seconds` metric) when running on a local testnet.
## Issue Addressed
Resolves#2262
## Proposed Changes
Add a new CLI flag `--beacon-nodes-tls-certs` which allows the user to specify a path to a certificate file (or a list of files, separated by commas). The VC will then use these certificates (in addition to the existing certificates in the OS trust store) when connecting to a beacon node over HTTPS.
## Additional Info
This only supports certificates in PEM format.
## Proposed Changes
Instead of checking for strict equality between a BN's spec and the VC's local spec, just check the genesis fork version. This prevents us from failing eagerly for minor differences, while still protecting the VC from connecting to a completely incompatible BN.
A warning is retained for the previous case where the specs are not exactly equal, which is to be expected if e.g. running against Infura before Infura configures the mainnet Altair fork epoch.
[EIP-3030]: https://eips.ethereum.org/EIPS/eip-3030
[Web3Signer]: https://consensys.github.io/web3signer/web3signer-eth2.html
## Issue Addressed
Resolves#2498
## Proposed Changes
Allows the VC to call out to a [Web3Signer] remote signer to obtain signatures.
## Additional Info
### Making Signing Functions `async`
To allow remote signing, I needed to make all the signing functions `async`. This caused a bit of noise where I had to convert iterators into `for` loops.
In `duties_service.rs` there was a particularly tricky case where we couldn't hold a write-lock across an `await`, so I had to first take a read-lock, then grab a write-lock.
### Move Signing from Core Executor
Whilst implementing this feature, I noticed that we signing was happening on the core tokio executor. I suspect this was causing the executor to temporarily lock and occasionally trigger some HTTP timeouts (and potentially SQL pool timeouts, but I can't verify this). Since moving all signing into blocking tokio tasks, I noticed a distinct drop in the "atttestations_http_get" metric on a Prater node:
I think this graph indicates that freeing the core executor allows the VC to operate more smoothly.
### Refactor TaskExecutor
I noticed that the `TaskExecutor::spawn_blocking_handle` function would fail to spawn tasks if it were unable to obtain handles to some metrics (this can happen if the same metric is defined twice). It seemed that a more sensible approach would be to keep spawning tasks, but without metrics. To that end, I refactored the function so that it would still function without metrics. There are no other changes made.
## TODO
- [x] Restructure to support multiple signing methods.
- [x] Add calls to remote signer from VC.
- [x] Documentation
- [x] Test all endpoints
- [x] Test HTTPS certificate
- [x] Allow adding remote signer validators via the API
- [x] Add Altair support via [21.8.1-rc1](https://github.com/ConsenSys/web3signer/releases/tag/21.8.1-rc1)
- [x] Create issue to start using latest version of web3signer. (See #2570)
## Notes
- ~~Web3Signer doesn't yet support the Altair fork for Prater. See https://github.com/ConsenSys/web3signer/issues/423.~~
- ~~There is not yet a release of Web3Signer which supports Altair blocks. See https://github.com/ConsenSys/web3signer/issues/391.~~
