Cosmos Transaction Collector

Task Description

Figure out which transactions on cosmos mainnet (cosmoshub-2) were done using Lunie.

We used special memos from within Lunie: (Sent via Lunie).

Requirements

• All transactions that were sent from Lunie are stored in some database.
• The database syncs and then stays up to date with the chain.
• The collector is dockerized.
• The docker container accepts an environment variable STARGATE which holds the url to a cosmos REST server that should be used to crawl the chain.

Advice

For testing purposes use https://stargate.cosmos.network (at the end using this endpoint wasn't really a good idea...). You can find API documentation here: https://cosmos.network/rpc/ We propose a simple REST server, but you can also provide a shell script.

Evaluation

• The docker container should provide some documented way to get the stored transactions.
• Important parts of your code should be unit tested
• The code should be documented
• The repo should have some information about the task
• You were able to follow the instructions

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Project Setup

First, you need to create a env file with the following lines:

STARGATE=https://lunie.mariopino.es:9070
MONGODIR=mongo

In case you are using the non-dockerized version, don't forget to install MongoDB and start it first with sudo service mongod start.

For docker, you just need to pull the mongo image: docker pull mongo

git clone https://github.com/anagutjor/lunie-transaction-collector

cd lunie-transaction-collector

npm i

Run the docker version

npm run docker

Run the not-dockerized version

npm run start OR npm start OR node index.js

Run tests

npm run test

Store Data from the Docker Container

To extract the data stored by the docker first you need the mongo container running. You can check if it is effectively running with docker ps. If you have npm run docker it will be up. If you only want to extract the data, you can also simply do docker run mongo to get only this container up and running.

Then do docker exec mongo sh -c 'exec mongodump --host localhost:27017 --out /dumps/' to create a dump folder within the docker container.

We will copy this dump folder into our system with: docker cp mongo:/dumps $HOME/Downloads/

Next, we only need to restore the transactionCollector database into our local system. For that, we will go to the Downloads directory with cd ~/Downloads and there execute mongorestore -d transactionCollector transactionCollector

Now we have the database also in our local system.

You could also connect to the docker mongo container with Robo 3T and creating a new connection using the container's ip in your system and port 27017.

To know the container's ip run this command, courtesy of StackOverflow: docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_id

Remember you'd need the mongo container running to establish a connection.

Remarks

1. Finally I didn't use the https://stargate.cosmos.network endpoint. The server providing this API was too faulty and slow, giving every now and then a 502 Error.

So I thank Mario for sharing with me his fantastic endpoint instead, at https://lunie.mariopino.es. What an incredible difference between the two of them!

2. It is important to note that in order to be able ro run the the crawler in both a docker container and localhost, I used an environment variable in schema.js, MONGODIR. This variable will change its value depending on whether we use the npm run start script or the npm run docker one.

The mechanism used to achieve this is quite straight-forward. Simply deleting the last line in the .env and rewriting it with the desired value (either localhost or mongo, the container name).