GET http://localhost:8090/v2/network/information returns 500 on mainnet while wallet is syncing through Byron era.

[piotr-iohk]

Context

Information	-
Version	2020.7.6 (git revision: 93c177b179fc4fc500858ebfbbf4ed7ecfc2c6bc)
Platform	Linux
Installation	From source

Steps to Reproduce

1. Start cardano-wallet-shelley on mainnet. (https://hydra.iohk.io/build/3627080/download/1/index.html)
2. While it is syncing (and also after it is synced, but still before HF) query

GET http://localhost:8090/v2/network/information 

Expected behavior

Information is available.

Actual behavior

The response was:
Code = 500,
Message = Something went wrong

in the log there is:

[cardano-wallet.network:Critical:206] [2020-07-27 13:54:16.34 UTC] Time interpreter queried past the horizon. This should not have happened.
Query is:
sqBind qBind QBind QBind QBind QAbsToRelEpoch EpochNo {unEpochNo = 208}
tHorizon [("runQuery",SrcLocEras are:
EraSummary {eraStart = Bound {boundTime = RelativeTime {getRelativeTime = 0s}, boundSlot = SlotNo {unSlotNo = 0}, boundEpoch = EpochNo {unEpochNo = 0}}, eraEnd = EraEnd (Bound {boundTime = RelativeTime {getRelativeTime = 89856000s}, boundSlot = SlotNo {unSlotNo = 4492800}, boundEpoch = EpochNo {unEpochNo = 208}}), eraParams = EraParams {eraEpochSize = EpochSize {unEpochSize = 21600}, eraSlotLength = SlotLength {getSlotLength = 20s}, eraSafeZone = StandardSafeZone 4320 NoLowerBound}}
CallStack (from HasCallStack):
  runQuery, called at src/Ouroboros/Consensus/HardFork/History/Qry.hs:302:44 in ouroboros-consensus-0.1.0.0-GJeJBwzkEl7AcixwXFgXER:Ouroboros.Consensus.HardFork.History.Qry
  interpretQuery, called at src/Cardano/Wallet/Primitive/Slotting.hs:309:26 in cardano-wallet-core-2020.7.6-AamOEQSEhy42ld6T94mTEW:Cardano.Wallet.Primitive.Slotting
  runQuery, called at src/Cardano/Wallet/Primitive/Slotting.hs:275:27 in cardano-wallet-core-2020.7.6-AamOEQSEhy42ld6T94mTEW:Cardano.Wallet.Primitive.Slotting
  mkTimeInterpreter, called at src/Cardano/Wallet/Shelley/Network.hs:456:60 in cardano-wallet-shelley-2020.7.6-2hcgUDLMQFX1xdHvgaYBva:Cardano.Wallet.Shelley.Network
  _timeInterpreterQuery, called at src/Cardano/Wallet/Shelley/Network.hs:307:33 in cardano-wallet-shelley-2020.7.6-2hcgUDLMQFX1xdHvgaYBva:Cardano.Wallet.Shelley.Network
  timeInterpreter, called at src/Cardano/Wallet/Network.hs:153:7 in cardano-wallet-core-2020.7.6-AamOEQSEhy42ld6T94mTEW:Cardano.Wallet.Network

---

Resolution

Two separate problems:

1. Even when synced, in Byron, it returns 500
2. When un-synced it returns 500

Explanation:

1. We use startTime =<< firstSlotInEpoch (e + 1) to get the time of the next epoch. This is just outside the horizon.
2. We throw if we can't get the network_tip or next_epoch.

Solution:

1. Get the end time of the current epoch, instead of the start time of the next one
2. Don't throw. Make network_tip and next_epoch optional

---

QA

Tested manually on mainnet.

When not in sync:

$ cardano-wallet-shelley network information
Ok.
{
    "node_tip": {
        "height": {
            "quantity": 2298589,
            "unit": "block"
        },
        "epoch_number": 106,
        "slot_number": 10480
    },
    "sync_progress": {
        "status": "syncing",
        "progress": {
            "quantity": 51.26,
            "unit": "percent"
        }
    }
}

When in sync:

{
    "network_tip": {
        "epoch_number": 207,
        "slot_number": 15728
    },
    "node_tip": {
        "height": {
            "quantity": 4484639,
            "unit": "block"
        },
        "epoch_number": 207,
        "slot_number": 15728
    },
    "sync_progress": {
        "status": "ready"
    },
    "next_epoch": {
        "epoch_start_time": "2020-07-29T21:44:51Z",
        "epoch_number": 208
    }

[Anviking]

Should be solved by #1943

[piotr-iohk]

lgtm