*This PR was adapted from @pawanjay176's work in #3197.*
## Issue Addressed
Fixes a regression in https://github.com/sigp/lighthouse/pull/3168
## Proposed Changes
https://github.com/sigp/lighthouse/pull/3168 added calls to `fork_choice` in `BeaconChain::per_slot_task` function. This leads to a panic as `per_slot_task` is called from an async context which calls fork choice, which then calls `block_on`.
This PR changes the timer to call the `per_slot_task` function in a blocking thread.
Co-authored-by: Pawan Dhananjay <pawandhananjay@gmail.com>
## Issue Addressed
Removes the build status badge from the main README.md. I don't think it actually serves a purpose and it also has the downside that a spurious failure gives us a red badge. For example, v2.2.1 failed with a [spurious failure](https://github.com/sigp/lighthouse/runs/5984392665?check_suite_focus=true) and I can't see a way to re-trigger that run. It will be red until our next release.
The same test suite runs when we merge into `unstable`, so those tests must have already passed in order for the commits to get onto `stable` (assuming our workflow is followed). Github will send notifications on failed CI, so we'll still be alerted to a failure without checking this badge.
## 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
NA
## Proposed Changes
Adds the configuration for the upcoming merge of the Ropsten network, as per:
https://github.com/eth-clients/merge-testnets/pull/9
Use the Ropsten network with: `lighthouse --network ropsten`
## Additional Info
This is still a work-in-progress. We should wait for the eth-clients/merge-testnets PR to be approved before merging this into our `unstable`.
## Issue Addressed
Upcoming spec change https://github.com/ethereum/consensus-specs/pull/2878
## Proposed Changes
1. Run fork choice at the start of every slot, and wait for this run to complete before proposing a block.
2. As an optimisation, also run fork choice 3/4 of the way through the slot (at 9s), _dequeueing attestations for the next slot_.
3. Remove the fork choice run from the state advance timer that occurred before advancing the state.
## Additional Info
### Block Proposal Accuracy
This change makes us more likely to propose on top of the correct head in the presence of re-orgs with proposer boost in play. The main scenario that this change is designed to address is described in the linked spec issue.
### Attestation Accuracy
This change _also_ makes us more likely to attest to the correct head. Currently in the case of a skipped slot at `slot` we only run fork choice 9s into `slot - 1`. This means the attestations from `slot - 1` aren't taken into consideration, and any boost applied to the block from `slot - 1` is not removed (it should be). In the language of the linked spec issue, this means we are liable to attest to C, even when the majority voting weight has already caused a re-org to B.
### Why remove the call before the state advance?
If we've run fork choice at the start of the slot then it has already dequeued all the attestations from the previous slot, which are the only ones eligible to influence the head in the current slot. Running fork choice again is unnecessary (unless we run it for the next slot and try to pre-empt a re-org, but I don't currently think this is a great idea).
### Performance
Based on Prater testing this adds about 5-25ms of runtime to block proposal times, which are 500-1000ms on average (and spike to 5s+ sometimes due to state handling issues 😢 ). I believe this is a small enough penalty to enable it by default, with the option to disable it via the new flag `--fork-choice-before-proposal-timeout 0`. Upcoming work on block packing and state representation will also reduce block production times in general, while removing the spikes.
### Implementation
Fork choice gets invoked at the start of the slot via the `per_slot_task` function called from the slot timer. It then uses a condition variable to signal to block production that fork choice has been updated. This is a bit funky, but it seems to work. One downside of the timer-based approach is that it doesn't happen automatically in most of the tests. The test added by this PR has to trigger the run manually.
## Issue Addressed
@z3n-chada is currently getting a `PayloadIdUnavailable` error when connecting lighthouse to Erigon and it's difficult to discern why so this just logs out the response status from the EE when we hit an `PayloadIdUnavailable` error
Co-authored-by: realbigsean <sean@sigmaprime.io>
## 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.
## Issue Addressed
Which issue # does this PR address?
#3114
## Proposed Changes
1. introduce `mime` package
2. Parse `Accept` field in the header with `mime`
## Additional Info
Please provide any additional information. For example, future considerations
or information useful for reviewers.
## Proposed Changes
Remove support for DB migrations that support upgrading from schema's below version 5. This is mostly for cosmetic/code quality reasons as in most circumstances upgrading from versions of Lighthouse this old will almost always require a re-sync.
## Additional Info
The minimum supported database schema is now version 5.
## Issue Addressed
N/A
## Proposed Changes
Prevents the early attester cache from producing attestations to future blocks. This bug could result in a missed head vote if the BN was requested to produce an attestation for an earlier slot than the head block during the (usually) short window of time between verifying a block and setting it as the head.
This bug was noticed in an [Antithesis](https://andreagrieser.com/) test and diagnosed by @realbigsean.
## Additional Info
NA
# 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).
## Proposed Changes
Remove the `lcli` code which performs block packing analysis.
The `lcli` code has been deprecated by a more performant version available in the HTTP API added in #2879.
## Additional Info
Any applications depending on the `lcli` code should migrate to the version in the HTTP API.
The only feature which is unavailable in the API version is an estimate of live/dead validators. This was originally used to determine a closer approximation of block packing efficiencies since offline validators have a disproportionate impact on efficiencies. However the implimentation in `lcli` is a poor approximation which cannot account for a multitude of factors. It is recommended to simply calculate relative efficiencies instead or use a more advanced method of determining live/dead validators.
## Proposed Changes
Reduce post-merge disk usage by not storing finalized execution payloads in Lighthouse's database.
⚠️ **This is achieved in a backwards-incompatible way for networks that have already merged** ⚠️. Kiln users and shadow fork enjoyers will be unable to downgrade after running the code from this PR. The upgrade migration may take several minutes to run, and can't be aborted after it begins.
The main changes are:
- New column in the database called `ExecPayload`, keyed by beacon block root.
- The `BeaconBlock` column now stores blinded blocks only.
- Lots of places that previously used full blocks now use blinded blocks, e.g. analytics APIs, block replay in the DB, etc.
- On finalization:
- `prune_abanonded_forks` deletes non-canonical payloads whilst deleting non-canonical blocks.
- `migrate_db` deletes finalized canonical payloads whilst deleting finalized states.
- Conversions between blinded and full blocks are implemented in a compositional way, duplicating some work from Sean's PR #3134.
- The execution layer has a new `get_payload_by_block_hash` method that reconstructs a payload using the EE's `eth_getBlockByHash` call.
- I've tested manually that it works on Kiln, using Geth and Nethermind.
- This isn't necessarily the most efficient method, and new engine APIs are being discussed to improve this: https://github.com/ethereum/execution-apis/pull/146.
- We're depending on the `ethers` master branch, due to lots of recent changes. We're also using a workaround for https://github.com/gakonst/ethers-rs/issues/1134.
- Payload reconstruction is used in the HTTP API via `BeaconChain::get_block`, which is now `async`. Due to the `async` fn, the `blocking_json` wrapper has been removed.
- Payload reconstruction is used in network RPC to serve blocks-by-{root,range} responses. Here the `async` adjustment is messier, although I think I've managed to come up with a reasonable compromise: the handlers take the `SendOnDrop` by value so that they can drop it on _task completion_ (after the `fn` returns). Still, this is introducing disk reads onto core executor threads, which may have a negative performance impact (thoughts appreciated).
## Additional Info
- [x] For performance it would be great to remove the cloning of full blocks when converting them to blinded blocks to write to disk. I'm going to experiment with a `put_block` API that takes the block by value, breaks it into a blinded block and a payload, stores the blinded block, and then re-assembles the full block for the caller.
- [x] We should measure the latency of blocks-by-root and blocks-by-range responses.
- [x] We should add integration tests that stress the payload reconstruction (basic tests done, issue for more extensive tests: https://github.com/sigp/lighthouse/issues/3159)
- [x] We should (manually) test the schema v9 migration from several prior versions, particularly as blocks have changed on disk and some migrations rely on being able to load blocks.
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Proposed Changes
Remove the bulky part of the EE integration test directory from the Docker build context so that we don't have to send 10GB of junk to the Docker daemon when building an image.
## 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
Resolves#3102
## Proposed Changes
- https://github.com/sigp/lighthouse/issues/3102#issuecomment-1114835063
- This is not an ideal solution, since the commit hash is missing from version number, but I think it is sufficient.
## Additional Info
I've tested ... :
- `fallback` is updated via `change_version.sh`.
```shell
$ cd scripts/
$ ./change_version.sh 2.2.1 2.2.2
$ git diff ../common/lighthouse_version/src/lib.rs
```
```diff
@ common/lighthouse_version/src/lib.rs:20 @ pub const VERSION: &str = git_version!(
// NOTE: using --match instead of --exclude for compatibility with old Git
"--match=thiswillnevermatchlol"
],
- prefix = "Lighthouse/v2.2.1-",
- fallback = "Lighthouse/v2.2.1"
+ prefix = "Lighthouse/v2.2.2-",
+ fallback = "Lighthouse/v2.2.2"
);
```
- a package built without git info prints expected version number (v2.2.1).
```shell
$ git archive HEAD --output=/tmp/lighthouse.zip
$ cd /tmp
$ unzip lighthouse.zip
$ cd lighthouse
$ cargo build --release
$ target/release/lighthouse --version
Lighthouse v2.2.1
BLS library: blst
SHA256 hardware acceleration: false
Specs: mainnet (true), minimal (false), gnosis (false)
```
## Issue Addressed
Fix a panic due to misuse of the Tokio executor when processing a forkchoiceUpdated response. We were previously calling `process_invalid_execution_payload` from the async function `update_execution_engine_forkchoice_async`, which resulted in a panic because `process_invalid_execution_payload` contains a call to fork choice, which ultimately calls `block_on`.
An example backtrace can be found here: https://gist.github.com/michaelsproul/ac5da03e203d6ffac672423eaf52fb20
## Proposed Changes
Wrap the call to `process_invalid_execution_payload` in a `spawn_blocking` so that `block_on` is no longer called from an async context.
## Additional Info
- I've been thinking about how to catch bugs like this with static analysis (a new Clippy lint).
- The payload validation tests have been re-worked to support distinct responses from the mock EE for newPayload and forkchoiceUpdated. Three new tests have been added covering the `Invalid`, `InvalidBlockHash` and `InvalidTerminalBlock` cases.
- I think we need a bunch more tests of different legal and illegal variations
## Proposed Changes
Recently, changes to Nethermind's Kiln branch have broken our integration tests.
This PR updates the chainspec to Kiln to ensure proper compatibility.
## Issue Addressed
N/A
## Proposed Changes
Previously, we were using `Sleep::is_elapsed()` to check if the shutdown timeout had triggered without polling the sleep. This PR polls the sleep timer.
## Issue Addressed
We still ping peers that are considered in a disconnecting state
## Proposed Changes
Do not ping peers once we decide they are disconnecting
Upgrade logs about ignored rpc messages
## Additional Info
--
## Issue Addressed
NA
## Proposed Changes
Disallow the production of attestations and retrieval of unaggregated attestations when they reference an optimistic head. Add tests to this end.
I also moved `BeaconChain::produce_unaggregated_attestation_for_block` to the `BeaconChainHarness`. It was only being used during tests, so it's nice to stop pretending it's production code. I also needed something that could produce attestations to optimistic blocks in order to simulate scenarios where the justified checkpoint is determined invalid (if no one would attest to an optimistic block, we could never justify it and then flip it to invalid).
## Additional Info
- ~~Blocked on #3126~~
## Issue Addressed
In very rare occasions we've seen most if not all our peers in a chain with which we don't agree. Purging these peers can take a very long time: number of retries of the chain. Meanwhile sync is caught in a loop trying the chain again and again. This makes it so that we fast track purging peers via registering the failed chain to prevent retrying for some time (30 seconds). Longer times could be dangerous since a chain can fail if a batch fails to download for example. In this case, I think it's still acceptable to fast track purging peers since they are nor providing the required info anyway
Co-authored-by: Divma <26765164+divagant-martian@users.noreply.github.com>
## Issue Addressed
Addresses sync stalls on v2.2.0 (i.e. https://github.com/sigp/lighthouse/issues/3147).
## Additional Info
I've avoided doing a full `cargo update` because I noticed there's a new patch version of libp2p and thought it could do with some more testing.
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
NA
## Proposed Changes
Fixes an issue introduced in #3088 which was causing unnecessary `crit` logs on networks without Bellatrix enabled.
## Additional Info
NA
## Issue Addressed
N/A
## Proposed Changes
https://github.com/sigp/lighthouse/pull/3133 changed the rpc type limits to be fork aware i.e. if our current fork based on wall clock slot is Altair, then we apply only altair rpc type limits. This is a bug because phase0 blocks can still be sent over rpc and phase 0 block minimum size is smaller than altair block minimum size. So a phase0 block with `size < SIGNED_BEACON_BLOCK_ALTAIR_MIN` will return an `InvalidData` error as it doesn't pass the rpc types bound check.
This error can be seen when we try syncing pre-altair blocks with size smaller than `SIGNED_BEACON_BLOCK_ALTAIR_MIN`.
This PR fixes the issue by also accounting for forks earlier than current_fork in the rpc limits calculation in the `rpc_block_limits_by_fork` function. I decided to hardcode the limits in the function because that seemed simpler than calculating previous forks based on current fork and doing a min across forks. Adding a new fork variant is simple and can the limits can be easily checked in a review.
Adds unit tests and modifies the syncing simulator to check the syncing from across fork boundaries.
The syncing simulator's block 1 would always be of phase 0 minimum size (404 bytes) which is smaller than altair min block size (since block 1 contains no attestations).
## Issue Addressed
NA
## Proposed Changes
Ensures that a `VALID` response from a `forkchoiceUpdate` call will update that block in `ProtoArray`.
I also had to modify the mock execution engine so it wouldn't return valid when all payloads were supposed to be some other static value.
## Additional Info
NA
## Issue Addressed
NA
## Proposed Changes
- Adds more checks to prevent importing blocks atop parent with invalid execution payloads.
- Adds a test for these conditions.
## Additional Info
NA
## Proposed Changes
Cut release v2.2.0 including proposer boost.
## Additional Info
I also updated the clippy lints for the imminent release of Rust 1.60, although LH v2.2.0 will continue to compile using Rust 1.58 (our MSRV).
## Proposed Changes
I did some gardening 🌳 in our dependency tree:
- Remove duplicate versions of `warp` (git vs patch)
- Remove duplicate versions of lots of small deps: `cpufeatures`, `ethabi`, `ethereum-types`, `bitvec`, `nix`, `libsecp256k1`.
- Update MDBX (should resolve#3028). I tested and Lighthouse compiles on Windows 11 now.
- Restore `psutil` back to upstream
- Make some progress updating everything to rand 0.8. There are a few crates stuck on 0.7.
Hopefully this puts us on a better footing for future `cargo audit` issues, and improves compile times slightly.
## Additional Info
Some crates are held back by issues with `zeroize`. libp2p-noise depends on [`chacha20poly1305`](https://crates.io/crates/chacha20poly1305) which depends on zeroize < v1.5, and we can only have one version of zeroize because it's post 1.0 (see https://github.com/rust-lang/cargo/issues/6584). The latest version of `zeroize` is v1.5.4, which is used by the new versions of many other crates (e.g. `num-bigint-dig`). Once a new version of chacha20poly1305 is released we can update libp2p-noise and upgrade everything to the latest `zeroize` version.
I've also opened a PR to `blst` related to zeroize: https://github.com/supranational/blst/pull/111
## Issue Addressed
N/A
## Proposed Changes
Fix the upper bound for blocks by root responses to be equal to the max merge block size instead of altair.
Further make the rpc response limits fork aware.
## Proposed Changes
Increase the default `--slots-per-restore-point` to 8192 for a 4x reduction in freezer DB disk usage.
Existing nodes that use the previous default of 2048 will be left unchanged. Newly synced nodes (with or without checkpoint sync) will use the new 8192 default.
Long-term we could do away with the freezer DB entirely for validator-only nodes, but this change is much simpler and grants us some extra space in the short term. We can also roll it out gradually across our nodes by purging databases one by one, while keeping the Ansible config the same.
## Additional Info
We ignore a change from 2048 to 8192 if the user hasn't set the 8192 explicitly. We fire a debug log in the case where we do ignore:
```
DEBG Ignoring slots-per-restore-point config in favour of on-disk value, on_disk: 2048, config: 8192
```
## Proposed Changes
Mitigate the fork choice attacks described in [_Three Attacks on Proof-of-Stake Ethereum_](https://arxiv.org/abs/2110.10086) by enabling proposer boost @ 70% on mainnet.
Proposer boost has been running with stability on Prater for a few months now, and is safe to roll out gradually on mainnet. I'll argue that the financial impact of rolling out gradually is also minimal.
Consider how a proposer-boosted validator handles two types of re-orgs:
## Ex ante re-org (from the paper)
In the mitigated attack, a malicious proposer releases their block at slot `n + 1` late so that it re-orgs the block at the slot _after_ them (at slot `n + 2`). Non-boosting validators will follow this re-org and vote for block `n + 1` in slot `n + 2`. Boosted validators will vote for `n + 2`. If the boosting validators are outnumbered, there'll be a re-org to the malicious block from `n + 1` and validators applying the boost will have their slot `n + 2` attestations miss head (and target on an epoch boundary). Note that all the attesters from slot `n + 1` are doomed to lose their head vote rewards, but this is the same regardless of boosting.
Therefore, Lighthouse nodes stand to miss slightly more head votes than other nodes if they are in the minority while applying the proposer boost. Once the proposer boost nodes gain a majority, this trend reverses.
## Ex post re-org (using the boost)
The other type of re-org is an ex post re-org using the strategy described here: https://github.com/sigp/lighthouse/pull/2860. With this strategy, boosted nodes will follow the attempted re-org and again lose a head vote if the re-org is unsuccessful. Once boosting is widely adopted, the re-orgs will succeed and the non-boosting validators will lose out.
I don't think there are (m)any validators applying this strategy, because it is irrational to attempt it before boosting is widely adopted. Therefore I think we can safely ignore this possibility.
## Risk Assessment
From observing re-orgs on mainnet I don't think ex ante re-orgs are very common. I've observed around 1 per day for the last month on my node (see: https://gist.github.com/michaelsproul/3b2142fa8fe0ff767c16553f96959e8c), compared to 2.5 ex post re-orgs per day.
Given one extra slot per day where attesting will cause a missed head vote, each individual validator has a 1/32 chance of being assigned to that slot. So we have an increase of 1/32 missed head votes per validator per day in expectation. Given that we currently see ~7 head vote misses per validator per day due to late/missing blocks (and re-orgs), this represents only a (1/32)/7 = 0.45% increase in missed head votes in expectation. I believe this is so small that we shouldn't worry about it. Particularly as getting proposer boost deployed is good for network health and may enable us to drive down the number of late blocks over time (which will decrease head vote misses).
## TL;DR
Enable proposer boost now and release ASAP, as financial downside is a 0.45% increase in missed head votes until widespread adoption.
## Proposed Changes
Add a `lighthouse db` command with three initial subcommands:
- `lighthouse db version`: print the database schema version.
- `lighthouse db migrate --to N`: manually upgrade (or downgrade!) the database to a different version.
- `lighthouse db inspect --column C`: log the key and size in bytes of every value in a given `DBColumn`.
This PR lays the groundwork for other changes, namely:
- Mark's fast-deposit sync (https://github.com/sigp/lighthouse/pull/2915), for which I think we should implement a database downgrade (from v9 to v8).
- My `tree-states` work, which already implements a downgrade (v10 to v8).
- Standalone purge commands like `lighthouse db purge-dht` per https://github.com/sigp/lighthouse/issues/2824.
## Additional Info
I updated the `strum` crate to 0.24.0, which necessitated some changes in the network code to remove calls to deprecated methods.
Thanks to @winksaville for the motivation, and implementation work that I used as a source of inspiration (https://github.com/sigp/lighthouse/pull/2685).
## 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
N/A
## Proposed Changes
- Update the JSON-RPC id field for both our request and response objects to be a `serde_json::Value` rather than a `u32`. This field could be a string or a number according to the JSON-RPC 2.0 spec. We only ever set it to a number, but if, for example, we get a response that wraps this number in quotes, we would fail to deserialize it. I think because we're not doing any validation around this id otherwise, we should be less strict with it in this regard.
## Additional Info
Co-authored-by: realbigsean <sean@sigmaprime.io>
## Issue Addressed
NA
## Proposed Changes
In the first Goerli shadow-fork, Lighthouse was getting timeouts from Geth which prevented the LH+Geth pair from progressing.
There's not a whole lot of information I can use to set these timeouts. The most interesting pieces of information I have are quotes from Marius from Geth:
- *"Fcu also needs to construct the block which can take 2sec"* ([Discord](https://discord.com/channels/595666850260713488/910910348922589184/958006487052066836))
- *"2 sec should be ok for new payload, weird that it times out"* ([Discord](https://discord.com/channels/595666850260713488/910910348922589184/958006487052066836))
I don't think we should be so worried about getting these timeouts correct now. No one really knows how long the various EEs are going to take, it's a bit too early in development. With these changes I'm giving some headroom so that we don't fail just because EEs are quite optimized enough. I've set the value to 6s (half a mainnet slot), since I think anything beyond 6s is an interesting problem that we want to know about sooner rather than later.
## Additional Info
NA
## Issue Addressed
N/A
## Proposed Changes
Set the engine state to `EngineState::Offline` if the engine api call fails during broadcast. This caused issues while pausing sync when the execution engine is offline because `EngineState` always returned `Synced`.
## Issue Addressed
N/A
## Proposed Changes
The slashing db import log showed the latest proposed block in the db as `latest block` which might be potentially confusing.
## Proposed Changes
Allow Lighthouse to speculatively create blocks via the `/eth/v1/validators/blocks` endpoint by optionally skipping the RANDAO verification that we introduced in #2740. When `verify_randao=false` is passed as a query parameter the `randao_reveal` is not required to be present, and if present will only be lightly checked (must be a valid BLS sig). If `verify_randao` is omitted it defaults to true and Lighthouse behaves exactly as it did previously, hence this PR is backwards-compatible.
I'd like to get this change into `unstable` pretty soon as I've got 3 projects building on top of it:
- [`blockdreamer`](https://github.com/michaelsproul/blockdreamer), which mocks block production every slot in order to fingerprint clients
- analysis of Lighthouse's block packing _optimality_, which uses `blockdreamer` to extract interesting instances of the attestation packing problem
- analysis of Lighthouse's block packing _performance_ (as in speed) on the `tree-states` branch
## Additional Info
Having tested `blockdreamer` with Prysm, Nimbus and Teku I noticed that none of them verify the randao signature on `/eth/v1/validator/blocks`. I plan to open a PR to the `beacon-APIs` repo anyway so that this parameter can be standardised in case the other clients add RANDAO verification by default in future.
