How to add pip dependencies to an electron

In this section, we illustrate the steps in adding a list of PyPI packages that are required to execute an electron.

First, let’s import covalent.

import covalent as ct
import numpy

We can then use the DepsPip class to declare which pip packages we want our electrons to depend on.

deps_pip = ct.DepsPip(packages=["numpy==1.22.4"])

@ct.electron(
    deps_pip=deps_pip,
)
def get_result():
    matrix = numpy.identity(3)
    return numpy.sum(matrix)

@ct.lattice
def workflow():
    return get_result()

We can then dispatch our workflow to get our result.

dispatch_id = ct.dispatch(workflow)()
r = ct.get_result(dispatch_id, wait=True)
print(r.result)

3.0

Alternatively, we can specify the path to a requirements.txt file that contains the list of required packages:

import os
with open('requirements_example.txt', 'w') as f:
    f.write('numpy==1.22.4')
f.close()

deps_pip=ct.DepsPip(reqs_path="./requirements_example.txt")

@ct.electron(
    deps_pip=deps_pip,
)
def get_result():
    matrix = numpy.identity(3)
    return numpy.sum(matrix)

@ct.lattice
def workflow():
    return get_result()

dispatch_id = ct.dispatch(workflow)()
r = ct.get_result(dispatch_id, wait=True)
print(r.result)

3.0

We can also add pip dependencies as call_before & call_after hooks on electrons.

@ct.electron(
    call_before=[ct.DepsPip(packages=["numpy==1.22.4"])],
    call_after=[ct.DepsPip(packages=["networkx==2.5"])]
)
def my_task():
    pass