Add API doc and general project description

DoD:

Endpoints:

• /genesis - returns all transactions from the genesis block

#DoD:

Endpoints:

• /snapshot/latest - returns the highest indexed snapshot
• /snapshot/{height} - returns snapshot by heght (long)
• /snapshot/{hash} - return snapshot by hash
• /snapshot/{height}/transaction - returns all transactions from the given snapshot
• /snapshot/{hash}/transaction - returns all transactions from the given snapshot
• /snapshot/latest/transaction - returns all transactions from the latest snapshot

Would it be possible to implement an endpoint where we can retrieve all wallet balances at a certain snapshot height?

With the new implementation of incremental snapshots, there is no easy way anymore to query this information from the node API, so it would be nice to have that query available in the block explorer.

The result of the API endpoint could looks something like this:
{ "ordinal": 0, "balances": { "DAGXXXX": 1000000000000, "DAGYYYY": 2000000000000, "DAGZZZZ": 3000000000000 } }

Thx!

DoD:

Endpoints:

• /transaction/{hash} - return transaction by hash
• /address/{dag_address}/transaction - all sent and received (sorted by timestamp DESC)
• /address/{dag_address}/transaction/sent - only sent (sorted by ordinal DESC)
• /address/{dag_address}/transaction/received - only received (sorted by timestamp DESC)

DoD

Endpoints:

• /address/{dag_address}/balance - returns balance for given address, from latest snapshot
• /balance/total - returns sum of all balances

Both endpoints should support ?height=# query parameter to return balances by the snapshot height. Default: latest

DoD:
Endpoint /transactions?sender=$address, currently return whole list.
Endpoint should have parameters size, page and should return the page.

AWS Lambda connection to elasticsearch

Ideally, we should map elasticsearch errors to our custom ones.
i.e. below we can see that elasticsearch returned 404 status code. It would be great not to return exact reason to end user.

Consider such a mapping:

Elasticsearch -> Our own

404 Not Found -> 404 Not Found
anything else -> 500 Internal Server Error

DoD:

Implement pagination in all endpoints returning large arrays:

• all transactions' endpoints
• snapshot transactions
• address list endpoint

Consider offset & limit + X-Total-Count header.

Currently errors on mainnet are visible to the end user. We would like to hide the explicit reason and return only the summary message.
I.e. for a given URL, the error returns the whole elasticsearch response with error message but it should return only a message, for example: "Transaction not found".

https://block-explorer.constellationnetwork.io/transaction/ee76a4b5315372aa2cdd8b98db453f28927bea630019795d0cee1ea58ccc637f

Additional things if possible:

• log the error
• hide errors based on the environment (env variables?) so on dev we will see the full log but on prod only the message

DoD

Endpoints:

• /address/count - returns count of all addresses
• /address - returns all addresses sorted DESC by balance

DoD:
Terraform configuration should be split into separate files/modules.

DoD:
The configuration file should be loaded from the private s3 bucket.

DoD:

Endpoints:

• /checkpoint-block/{hash} - returns checkpoint block by hash