algo-app-dev 0.3.0

Utilities to help in the development of PyTeal contracts for Algorand.

Algo App Dev

Utilities to help in the development of PyTeal contracts for Algorand.

Installation

You should install the package globally so that using commands run with sudo -u algorand can access to the package and binaries.

sudo pip install -U algo-app-dev

Pre-requisits

In this documentation, it is assumed that you are running an algorand node in an Ubuntu environment.

You can install algorand with following these commands:

sudo apt-get update
sudo apt-get install -y gnupg2 curl software-properties-common
curl -O https://releases.algorand.com/key.pub
sudo apt-key add key.pub
rm -f key.pub
sudo add-apt-repository "deb [arch=amd64] https://releases.algorand.com/deb/ stable main"
sudo apt-get update
sudo apt-get install algorand

Command line utilities

The following command line utilities are isntalled with the package. They help streamline some common system tasks realting to algorand devleopment:

• aad-make-node: this command can be used to setup a private, and private development node
• aad-run-node: this command can be used to start or stop node daemons

Modules

The following is a brief overview of the package's functionality and organization:

clients

The clients module contains a few utilities to help manage the algod and kmd daeomon clients.

There are also utilities to help extract key-value information from global and local state queries.

transactions

The transactions module contains utilities to help create and manage transactions.

apps

The apps module contains utilities and classes to help construct and manage stateful applications (stateful smart contracts). This is the core of the package.

Most the app development work utilizes two classes: the State and AppBuilder classes. These help reduce the amount of boiler-plate needed to create functional pyteal expressions.

Manually managing the app's state is very error prone. The interface provided by State and its derived StateGlobal, StateGlobalExternal, StateLocal and StateLocalExternal can reduce these errors.

Here is an example of a very simple app with a global counter. Every time a (no-op) call is made with the argument "count", it increments the counter.

# define the state: a single global counter which defaults to 0
state = apps.StateGlobal(
    [apps.State.KeyInfo(key="counter", type=tl.Int, default=tl.Int(0))]
)
# define the logic: invoking with the argument "count" increments the counter
app_builder = apps.AppBuilder(
    invocations={
        "count": tl.Seq(
            state.set("counter", state.get("counter") + tl.Int(1)),
            tl.Return(tl.Int(1)),
        ),
    },
    global_state=state,
)
# build the transaction which can be sent to create the app
txn = app_builder.create_txn(
    algod_client, funded_account.address, algod_client.suggested_params()
)
# send the transaction and get back out the app's id and address
txid = algod_client.send_transaction(txn.sign(funded_account.key))
txn_info = transactions.get_confirmed_transaction(algod_client, txid, WAIT_ROUNDS)
app_meta = AppMeta.from_result(txn_info)

The resulting app_meta object:

AppMeta(app_id=2, address='...')

dryruns

The dryruns module contais utilities to help send dry runs to a node, and parse the results.

Here is how the dryruns utilities could be used to test the contract:

txn = ApplicationNoOpTxn(
    funded_account.address,
    algod_client.suggested_params(),
    app_meta.app_id,
    ["count"],
)
result = algod_client.dryrun(
    dr.builder_run(stxn=txn.sign(funded_account.key), app_builder=app_builder)
)
for item in dr.get_trace(result):
    print(item)
for delta in dr.get_global_deltas(result):
    print(delta)

The end of the stack trace might look something like:

...
app_global_get → [b'counter', 0]
intc_0 // 1 → [b'counter', 0, 1]
+ → [b'counter', 1]
app_global_put → []
intc_0 // 1 → [1]
return → [1]

And the only delta is:

KeyDelta(key=b'count', value=1)

Testing

NOTE: in order to use the testing functionality, you must install the dev dependencies. This is done with the command:

sudo pip install -U algo-app-dev[dev]

You should run tests as the algorand user so that the tests can access the local daemons. The daemon access token file can be ready only by the algorand user.

Start the daemons before testing, and optionally stop them after the tests run.

The tests make calls to the node, which is slow. There are two mitigations for this: using the dev node, and using the pytest-xdist plugin for pytest to parallelize the test.

The dev node creates a new block for every transaction, meaning that there is no need to wait for consensus. Whereas testing with private_dev can take a 10s of seconds, testing with pivate takes 10s of minutes.

The flag -n X can be used to split the tests into that many parallel processes.

sudo -u algorand aad-run-node private_dev start
sudo -u algorand pytest -n 4 tests/
sudo -u algorand aad-run-node private_dev stop

PyTest envioronment

The module algoappdev.testing contains some pytest fixutres that are widely applicable. If you want to make those fixutres available to all your tests, you can create a file conftest.py in your test root directory and write to it:

# conftest.py
from algoappdev.testing import *

It also exposes two variables which can be configured through environment variables:

• NODE_DIR: this should be the path to the node data to work with.
• WAIT_ROUNDS: this should be set to the maximun number of rounds to await transaction confirmations.

Both are read from the environment varible with corresponding name prefixed with AAD_.

NODE_DIR defaults to the private dev node data path. If your system is configured differently, you will need to set this accordingly.

WAIT_ROUNDS defaults to 1, because when interacting with a dev node transactions are immediately committed. If doing integration tests with a non-dev node, this should be increased to give time for transactions to complete before moving onto another test.