How to get the current epoch and slot via API?

nirvanush · 7 September 2021 19:16

Hi, I want to display a cardano-node sync progress bar in my app. So I can query the epoch my node is up to during syncing, but how can I know what’s the latest epoch/slot out there (in the world)?

Is there any publicly available API for that?

mcrio · 7 September 2021 20:20

See how guild operators calculate it. You can calculate it based on parameters from the genesis files:

github.com

cardano-community/guild-operators/blob/6c5cec520bdced0d9b5b455968c400f67a5bf281/scripts/cnode-helper-scripts/env#L455

    
      
              SHELLEY_TRANS_EPOCH=-1
              return 1
            else
              SHELLEY_TRANS_EPOCH=${byron_epochs}
              return 0
            fi
          }
          [[ ${OFFLINE_MODE} = "N" && ${SHELLEY_TRANS_EPOCH} -eq -1 ]] && getNodeMetrics && getShelleyTransitionEpoch
          
          
# Description : Offline calculation of current epoch based on genesis file
          getEpoch() {
            current_time_sec=$(printf '%(%s)T\n' -1)
            [[ ${SHELLEY_TRANS_EPOCH} -eq -1 ]] && echo 0 && return
            byron_end_time=$(( BYRON_GENESIS_START_SEC + ((SHELLEY_TRANS_EPOCH * BYRON_EPOCH_LENGTH * BYRON_SLOT_LENGTH) / 1000) ))
            echo $(( SHELLEY_TRANS_EPOCH + ( (current_time_sec - byron_end_time) / SLOT_LENGTH / EPOCH_LENGTH ) ))
          }
          
          
# Description : Offline calculation of current epoch based on provided slot number
          getEpochFromSlot() {
            echo $(( SHELLEY_TRANS_EPOCH + (($1 - (SHELLEY_TRANS_EPOCH * BYRON_EPOCH_LENGTH)) / EPOCH_LENGTH) ))
          }

nirvanush · 7 September 2021 21:53

Thank you! I’ll try that

nirvanush · 7 September 2021 22:36

Lol! I’ve rewrote this function to JS just to discover that in Alonzo they’ve added syncProgress to the response

{
    "epoch": 155,
    "hash": "42f877bcbd10ed80f24209593525a3a6798c5c06472b9aea4407d8b5f8cf0bab",
    "slot": 36684644,
    "block": 2893622,
    "era": "Alonzo",
    "syncProgress": "100.00"
}

Markus-VITAL · 8 September 2021 02:45

Hehe, this makes it easier
If you want to know how old the TIP is you can also take a look at my little TIP Reporting Script:

github.com

ResponsibleStaking/Cardano-SPO-Scripts/blob/main/pingTipCheck.sh

#!/usr/bin/env bash
# shellcheck disable=SC2034,SC2086,SC2230,SC2009,SC2206,SC2062,SC2059
# Replace YOUR-USERNAME and YOUR-PING-ID below. You need a Healthcheck.io Account

CARDANO_CLI_PATH=                                       #Set the name which was used for Installing CNODE. - e.g. /home/YOUR-USERNAME/.cabal/bin/cardano-cli
                                                        #Make sure to replace YOUR-USER
HEALTHCHECKS_PING_URL=                                  #Copy and Paste the full Ping URL from Healthcheks.IO - e.g. https://hc-ping.com/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee
ACCEPTED_TIP_DIFF=60                                    #How many seconds are OK before starting to not send OK signals to Healthcheks?

######################################
# Do NOT modify code below           #
######################################

export CARDANO_NODE_SOCKET_PATH=/opt/cardano/cnode/sockets/node0.socket

customCurrentSlotNoString=$($CARDANO_CLI_PATH query tip --mainnet | grep -Po '\"slot\": \K[0-9]+')
customCurrentSlotNo=$(expr $customCurrentSlotNoString + 0)

customRefSlotNo=$(expr $(printf '%(%s)T\n' -1) - 1591566291)
customDiff=$(expr $customRefSlotNo - $customCurrentSlotNo)

This file has been truncated. show original

Instructions: https://github.com/ResponsibleStaking/Cardano-SPO-Scripts

ADAMOONPOOL · 8 September 2021 06:42

You can also try blockfrost API, https://blockfrost.io/

Topic		Replies	Views
Check sync status of node Operate a Stake Pool	29	5402	11 October 2022
The APIs to get slot and epoch of Cardano Community Technical Support	0	614	5 February 2018
How to get current epoch and current slot from cardano-cli Setup a Stake Pool	9	3200	5 March 2021
Testnet shelley epoch Community Technical Support	0	344	9 July 2021
How to calculate slot within an epoch from total slot number? Operate a Stake Pool	0	468	26 November 2022

How to get the current epoch and slot via API?

Related topics