cosmos-sdk/docs/guide/basecoin-basics.md

Basecoin Basics

Here we explain how to get started with a simple Basecoin blockchain, and how to send transactions between accounts using the basecoin tool.

Install

Make sure you have basecoin installed. You will also need to install tendermint.

Initialization

Basecoin is an ABCI application that runs on Tendermint, so we first need to initialize Tendermint:

tendermint init

This will create the necessary files for a single Tendermint node in ~/.tendermint. If you had previously run tendermint, make sure you reset the chain (note this will delete all chain data, so back it up if you need it):

tendermint unsafe_reset_all

Now we need some initialization files for basecoin. We have included some defaults in the basecoin directory, under data. For purposes of convenience, change to that directory:

cd $GOPATH/src/github.com/tendermint/basecoin/data

The directory contains a genesis file and two private keys.

You can generate your own private keys with tendermint gen_validator, and construct the genesis.json as you like.

Start

Now we can start basecoin:

basecoin start --in-proc

This will initialize the chain with the genesis.json file from the current directory. If you want to specify another location, you can run:

basecoin start --in-proc --dir PATH/TO/CUSTOM/DATA

Note that --in-proc stands for "in process", which means basecoin will be started with the Tendermint node running in the same process. To start Tendermint in a separate process instead, use:

basecoin start

and in another window:

tendermint node

In either case, you should see blocks start streaming in!

Send transactions

Now we are ready to send some transactions. If you take a look at the genesis.json file, you will see one account listed there. This account corresponds to the private key in priv_validator.json. We also included the private key for another account, in priv_validator2.json.

Let's check the balance of these two accounts:

basecoin account 0xD397BC62B435F3CF50570FBAB4340FE52C60858F
basecoin account 0x4793A333846E5104C46DD9AB9A00E31821B2F301

The first account is flush with cash, while the second account doesn't exist. Let's send funds from the first account to the second:

basecoin sendtx --to 0x4793A333846E5104C46DD9AB9A00E31821B2F301 --amount 10

By default, the CLI looks for a priv_validator.json to sign the transaction with, so this will only work if you are in the $GOPATH/src/github.com/tendermint/basecoin/data. To specify a different key, we can use the --from flag.

Now if we check the second account, it should have 10 coins!

basecoin account 0x4793A333846E5104C46DD9AB9A00E31821B2F301

We can send some of these coins back like so:

basecoin sendtx --to 0xD397BC62B435F3CF50570FBAB4340FE52C60858F --from priv_validator2.json --amount 5

Note how we use the --from flag to select a different account to send from.

If we try to send too much, we'll get an error:

basecoin sendtx --to 0xD397BC62B435F3CF50570FBAB4340FE52C60858F --from priv_validator2.json --amount 100

See basecoin sendtx --help for additional details.

Plugins

The sendtx command creates and broadcasts a transaction of type SendTx, which is only useful for moving tokens around. Fortunately, Basecoin supports another transaction type, the AppTx, which can trigger code registered via a plugin system.

For instance, we implemented a simple plugin called counter, which just counts the number of transactions it processed. To run it, kill the other processes, run tendermint unsafe_reset_all, and then

basecoin start --in-proc --counter-plugin

Now in another window, we can send transactions with:

TODO

Next steps

1. Learn more about Basecoin's design
2. Make your own cryptocurrency using Basecoin plugins
3. Learn more about plugin design
4. See some more example applications
5. Learn how to use InterBlockchain Communication (IBC)
6. Deploy testnets running your basecoin application.