The Glassnode Code Challenge is an opportunity to demonstrate your problem solving skills which we value a lot at Glassnode.
The challenge is specified a bit loosely on purpose to let you demonstrate your ability to take intermediate decisions by your own and your ability to explore a previously unknown topic by yourself. Results of this challenge will be an entrypoint for the further tech interview.
Users of the Ethereum network are required to pay for each action a certain
amount of ETH (called fees) roughly according to the following formula: kind of action * the gas price. Generally, the gas price increases in times of
high activity/overloading, consequently increasing the total amount of fees
spent by users. Ethereum recently experienced a significant increase in gas
prices. It's interesting to analyze how much fees were spent by users on different
kinds of actions. This can give insight into what kinds of actions were responsible
for the increased gas prices. We can do this, by first filtering the transactions on the
kind we are interested in and then summing the fees spent on those transactions.
For this task, we're interested in how much fees in the Ethereum network have
been spent by plain ETH transfers. So we want you to compute the hourly
amount of fees spent by transactions between externaly owned accounts
(EOA). A transaction is considered to be between two EOA addresses if it's a
direct ETH value transfer, i.e. to and from addresses of such a
transaction should not be one of the contracts and not a special address
0x0000000000000000000000000000000000000000 used for contract creation. Fee
computation is done in the following fashion: gas_used * gas_price. And of course we need some API to serve that information to the
public.
Provided repository includes a docker-compose.yaml (docker-compose docs)
with a database service in it, which represents a preconfigured postgres database
with a data snapshot of Ethereum transactions for a single day (07.09.2020). Contract
addresses are present in the provided database in the contracts table, and transactions
themselves in the transactions table. Note, that gas_price is stored in Wei units in
the data snapshot.
The end solution should be a REST API service listening on the port 8080
with an endpoint which serves data in the following JSON format:
[
{
"t": 1603114500,
"v": 123.45
},
...
]
Where t is a unix timestamp of the hour, and v is the amount of fees
being paid for transactions between EOA addresses within that hour in
ETH units. This service should be added to the services list in the provided
docker-compose.yaml and the solution must be able to start using
docker-compose up command.
You're free to choose the path and parameters for the endpoint as well as the service implementation language (but prefereably it should be golang).
- We respect your time and the challenge is designed in such a way as not to take more than 3-4 hours.
- Generate a repository for your solution from the provided template ("Use this template" button on github), and us a link to your repo when you're done.
- In your repo create
Solution.mdwith a description of your reasoning behind technical choices: trade-offs you might have made, anything you left out, or what you might do differently if you would had additional time.