Assignment: Interacting with the Cardano Node

Artifact

A small multi-command Go CLI, built on gOuroboros, that connects to a Cardano node and reports on it: current chain tip and sync state, the contents of a specific block, and the node's pending mempool.

Required Task

Using the gOuroboros Starter Kit as your starting point, build a command-line tool that talks directly to a Cardano node over the Ouroboros protocols. Give it commands that each exercise a different mini-protocol:

tip / sync — connect via ChainSync and report the chain tip and how far the node has synced.
block — fetch a specific block via BlockFetch and print its identifying fields (slot, hash, transaction count).
mempool — query the node's pending transactions via LocalTxMonitor.

This is the node-interaction plumbing the DNS CLI sits on: before it can register or resolve a name, it needs to reach a node, know the chain is current, read blocks, and see what's pending. A Cobra structure here also carries straight over from 099.3.

The first three commands run over Node-to-Node (N2N) against a public preprod relay (magic 1) — e.g. preprod-node.world.dev.cardano.org:3001 (more relays in the Cardano environments list). The mempool command uses Node-to-Client (N2C) over a local Unix socket and therefore requires a local node — Dingo (Preview, magic 2) or cardano-node in Docker. If you don't run a local node, complete the first three commands against a relay and note the mempool command as infra-blocked.

Additional Exploration

Close the loop with submission: send a transaction (reuse your Module 102 wallet/builder, or the starter kit's TxSubmission path) and have your mempool command show it sitting in the local node's mempool before it's included in a block. As a lighter stretch, point tip at two different relays and observe whether they report the same tip slot.

Deliverables

Code — public repo or gist with the runnable CLI (gOuroboros, multi-command). The README lists each command and how to run it.
Runtime evidence — captured terminal output for each capability:tip/sync — connection established plus the reported chain tip and sync state.block — a specific block's slot, hash, and transaction count.mempool — the query result (pending transaction hashes, or an explicit "mempool empty"). Include the tip slot/block hash so it can be cross-checked on Cardanoscan Preprod.
- tip/sync — connection established plus the reported chain tip and sync state.
- block — a specific block's slot, hash, and transaction count.
- mempool — the query result (pending transaction hashes, or an explicit "mempool empty"). Include the tip slot/block hash so it can be cross-checked on Cardanoscan Preprod.
Connection note — for each command, which access mode and endpoint you used (public relay over N2N vs. local node over N2C) and the network magic.
Course feedback (required): Written feedback on Module 101's lessons covering:Quality — what was clear, what was confusing, what was missing.Correctness — any code that didn't run, commands that failed, or steps that were wrong/out of date (cite the lesson number, e.g. 101.2).
- Quality — what was clear, what was confusing, what was missing.
- Correctness — any code that didn't run, commands that failed, or steps that were wrong/out of date (cite the lesson number, e.g. 101.2).

Assessment Criteria

SLT 101.1 — pass when the code connects to a node via gOuroboros (ChainSync, N2N) and the output shows a live connection.
SLT 101.2 — pass when the code fetches a specific block via BlockFetch and the output shows that block's identifying fields (slot, hash).
SLT 101.3 — pass when the program reports the node's sync state — the chain tip and how far the node has synced toward it.
SLT 101.4 — pass when the program queries the mempool via LocalTxMonitor against a local node and the output shows the result (pending tx hashes or an explicit empty mempool). Requires a local node; if infra-blocked, the learner must show the working code and a clear account of the blocker.
Course feedback — pass when feedback is specific and lesson-referenced (not "it was good"); flags at least one correctness issue OR one concrete improvement.

Notes