Running a local dev node
Installation
To install gnodev, simply clone the monorepo, and run make install:
git clone git@github.com:gnolang/gno.git
cd gno && make install
Overview
In this tutorial, you will learn how to run up a local development node with
gnodev. By spinning up a local Gno.land
node, users can simulate the blockchain environment locally on their machines,
allowing them to easily see how their code behaves before deploying it to a
remote Gno.land network.
This tutorial will show you how to use gnodev, a local development solution stack offering a built-in Gno.land node with a hot-reload feature for packages and realms, as well as a built-in instance of gnoweb.
Primary features
Apart from providing a built-in Gno.land node and a gnoweb instance, gnodev
also provides an array of other useful features. Let's explore the three most
prominent ones:
- Automatic package deployment
- Premining balances
- Hot reload
If you're familiar with the features above, jump to the practical example section.
gnodev also provides many useful features such as loading genesis transactions,
resolving packages from remote networks, modifying the built-in node parameters,
etc. Check out the full gnodev developer guide for more information.
1. Automatic deployment
gnodev automatically deploys your contracts to the built-in node, making
them readily accessible via gnoweb. This means that developers do not need to
manually deploy their contracts during local development.
Packages and realms are deployed with a default Gno address1, which can be changed
via the -deploy-key flag.
Detecting package paths
If the current working directory contains a gnomod.toml file, gnodev deploys the
package to the pkgpath specified inside. Check out this page
for more info.
If no gnomod.toml file is found, gnodev searches for a .gno file containing a
package name and deploys it under gno.land/r/dev/<pkgname>.
Deploying example packages
In addition to your working directory, gnodev automatically deploys all packages
and realms located in the examples/ folder
from the monorepo it was installed from. This makes all packages in the examples/
folder available for use during development. gnodev also provides the option
to resolve packages from a remote testnet, which can be set via the -resolver flag.
2. Premining balances
gnodev automatically detects your Gno keys from the local gnokey keybase, and
pre-mines a large amount of testnet GNOT to all of your addresses, which can
then be used for testing applications.
You can verify the balance of your addresses by pressing A when gnodev is running:
Accounts ┃ I (2) known keys
┃ table=
┃ │ KeyName Address Balance
┃ │ test1 g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5 10000000000000ugnot
┃ │ MyKey g1q4q3uegdnq9rsvf3xgxydr3yqd2v6w2tww5920 10000000000000ugnot
This simplifies development by removing the need to manually acquire testnet GNOT. This is not the case for remote testnets, where users must obtain testnet GNOT from faucets, such as the ones found on faucet.gno.land.
3. Hot reload
gnodev watches the current working directory for any changes that happen within
your code, and automatically reloads the built-in node, while trying to replay
previous transactions to maintain the state of your smart contracts between
code changes.
Directory watching, as well as transaction replaying, can be disabled with the
-no-watch and -no-replay flags, respectively.
With the main features of gnodev out of the way, let's dive into a practical
example.
Practical example
Let's use the local file structure we set up in the previous tutorial:
counter/
├─ gnomod.toml
├─ counter.gno
Let's go into the counter folder and run gnodev:
cd counter
gnodev
You should receive an output similar to the following:
❯ gnodev
Loader ┃ I guessing directory path path=gno.land/r/example/counter dir={your_pwd}
Accounts ┃ I default address imported name=test1 addr=g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5
Node ┃ I packages paths=[gno.land/r/example/counter]
Event ┃ I sending event to clients clients=0 type=NODE_RESET event=&{}
GnoWeb ┃ I gnoweb started lisn=http://127.0.0.1:8888
--- READY ┃ I for commands and help, press `h` took=1.391020125s
By opening the gnoweb listener address, http://localhost:8888,
we should see the render of our counter realm:
Current counter value: 0
Modifying Render()
Let's modify the Render() function inside counter.gno as follows, importing
the strconv package:
func Render(_ string) string {
return "My amazing counter value: " + strconv.Itoa(count)
}
gnodev will automatically detect the change in the file and reload both the node
and gnoweb. The render of our realm will then change:
My amazing counter value: 0
Interacting with the realm
To interact with our counter realm, let's create a simple transaction calling
the Increment() function with gnokey, using the key we created in the
in with gnokey.
Running the following command in your terminal will execute the transaction:
gnokey maketx call \
-pkgpath "gno.land/r/example/counter" \
-func "Increment" \
-args "42" \
-gas-fee 1000000ugnot \
-gas-wanted 20000000 \
-broadcast \
{MYKEY}
After entering the keypair password, you should get a response similar to this:
Enter password.
(42 int)
OK!
GAS WANTED: 20000000
GAS USED: 126933
HEIGHT: 203
EVENTS: []
TX HASH: k+WuKgPpoAg+EcR2EnzqxeWqUXB4KhOhg3l6zthSy0I=
Looking at the render of our realm, we'll see that the value of the counter has increased, as expected:
My amazing counter value: 42
The above section showcases a simple gnokey command that will execute a
transaction executing Increment(42) in the counter realm, which lives on the
gno.land/r/example/counter package path on the local node.
A detailed explanation how to use gnokey will be provided in an
upcoming tutorial.
After running gnodev, you can access several components:
- A local version of gnoweb
- A local blockchain instance for testing
- The web-based gnodev UI to monitor your node
Footnotes
-
The default deployer address is
g1jg8mtutu9khhfwc4nxmuhcpftf0pajdhfvsqf5, a.k.a.test1- the mnemonic phrase for this address is publicly known. ↩