Random notes from BU

random_bu.md

SQL

Histogram queries

select
  (age/10)*10 as from_age, -- Bucket unique
  ((age/10)*10)+10 as to_age,
  count(*),
  repeat('=', (count(*) * 30 / max(count(*)) over ())::int) as bar
from users
group by 1
order by 1;

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Psql

Psql local copying

psql ... -Xf ~/q.sql --csv > /tmp/TODO.csv

\copy (
) to '/tmp/TODO.csv' csv header

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MitmProxy

Debug a remote website

From Getting Started

• Configure the web browser to use localhost:8080 as proxy.
• Start mitmproxy.
• If not done before, go to http://mitm.it/ and install the CA cert.
• To intersect requests press and use ~u <regex> & ~q (see the docs)

Reverse proxy local service

Eg. for localhost:3000

mitmproxy -p 4000 --set console_focus_follow --mode reverse:http://localhost:3000/ --set modify_headers="/~q/Origin/http://localhost:3000"

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Git

git rebase --onto

Example: Merging on staging is difficult because of diverging histories. You could cherry-pick each commit, or:

# Ensure staging is up-to-date
git checkout staging
git pull

# Ensure my-branch is up-to-date with master (optional but good)
git checkout my-branch
git rebase origin/master

# Make a temp branch from my-branch
git checkout -b temp

# Rebase it from it's chosen parent (here origin/master but can use other to cut
# in a different place, or when not having rebase before) on top of staging.
# Now temp is `origin/staging --> your-commits` which is what you want staging
# to look like
git rebase --onto origin/staging origin/master

# Go staging and reset the pointer to temp. Done
git checkout staging
git reset --hard temp

# Let the world know...
git push