Example for Medium post: https://medium.com/@johnnyopao/python-dependencies-and-aws-lambda-18acbdebca20

handler.py

import os
import sys

CWD = os.path.dirname(os.path.realpath(__file__))
sys.path.insert(0, os.path.join(CWD, "lib"))

# The example below was taken and modified from the pyjags documentation
# https://pyjags.readthedocs.io/en/latest/getting_started.html

import pyjags
import numpy as np

np.random.seed(0)
np.set_printoptions(precision=1)

N = 500
a = 70
b = 4
sigma = 50

x = np.random.uniform(0, 100, size=N)
y = np.random.normal(a + x*b, sigma, size=N)

code = '''
model {
    for (i in 1:N) {
        y[i] ~ dnorm(alpha + beta * x[i], tau)
    }
    alpha ~ dunif(-1e3, 1e3)
    beta ~ dunif(-1e3, 1e3)
    tau <- 1 / sigma^2
    sigma ~ dgamma(1e-4, 1e-4)
}
'''

model = pyjags.Model(code, data=dict(x=x, y=y, N=N), chains=4)
samples = model.sample(500, vars=['alpha', 'beta', 'sigma'])

def summary(samples, varname, p=95):
    values = samples[varname]
    ci = np.percentile(values, [100-p, p])
    return '{:<6} mean = {:>5.1f}, {}% credible interval [{:>4.1f} {:>4.1f}]'.format(
      varname, np.mean(values), p, *ci)

def main(event, context):
    print('Did stuff with pyjags')

    return {
        'Summary': summary(samples, 'alpha')
    }


if __name__ == "__main__":
    main('', '')