chuckwondo

chuckwondo

#-------------------------------------------------------------------------------
# This assumes the following:
#
# 1. You have an Earthdata Login (EDL) account (https://urs.earthdata.nasa.gov/)
# 2. You have supplied your EDL credentials in either a .netrc file or
#    via the environment variables EARTHDATA_USERNAME and EARTHDATA_PASSWORD or
#    an EDL token via the environment variable EARTHDATA_TOKEN.
# 3. You have a Python virtual environment or conda environment with earthaccess
#    installed.
#-------------------------------------------------------------------------------

chuckwondo

Concurrent pystac-client Search Queries

Motivation: Implement async requests

This is a very simple performance comparison between approaches for running search queries via pystac-client:

• sequential (baseline)
• asyncio with HTTPX library
• greenlets with gevent library

chuckwondo

chuckwondo

Cumulus Verify Granules

Task

Write a new Lambda function using Node.js that validates the checksums of granule files based on the following guidelines:

• If all checksums are valid, the lambda handler should return nothing
• If any checksums are invalid, the lambda handler should throw a specific error
• If a file does not include a checksum or checksum type, ignore it

chuckwondo

Python Tail-Call Optimization

In order to avoid causing a stack overflow during recursion, do the following:

1. Ensure each recursive call is a tail call
2. Decorate the recursive function(s) with thunk (in the case of co-recursive functions, decorate both). This exposes a trampoline function, which is used in the next step.
3. Append a call to trampoline to only the initial call to each decorated function. Conversely, do not append a call to trampoline to any recursive call to a thunk-decorated function.

For example, suppose we have the following naive recursive implementation of the factorial function:

chuckwondo

chuckwondo