deploydemo

Fun and exciting ways to deploy a standard web app backend

This is a demo

The code is undoubtedly horrible.

The ideas are good tho. Like...

A/B Testing
Experiment Groups
Canary Deployments
Red/Green Deployments
Zero-Downtime Deployments
That sort of thing

Zero Downtime Demo

Good luck.

Demo Notes:

(this is kind of a script, but needs to be cleaned up). Apologies that these only appear in Main - keep this open in an editor since the file will go away when you git checkout things!

open 4 terminals to the demo repo Open chrome to pgadmin, locust, github, whatever (not everything will be up yet)

git checkout main

docker-compose up -d pgadmin
docker-compose up -d demo-postgres

Show tags:

git tag
git checkout v1.0.0
make docker-start
make db-upgrade

./demo/demo/POST\_test.sh
show postgres
show http://localhost:8000/users/

curl -X PATCH -H "Content-Type: application/json" -d '{"name":"Paul Simon", "userid":"1"}' http://localhost:8000/user/
show postgres
show http://localhost:8000/users/

Show locust users:

make perftest
browse to locust and see

PAUSE HERE FOR APPLAUSE

git checkout v2.0.0
make db-upgrade

FAIL FAIL FAIL

Check pgadmin
Check Locust - FAIL FAIL
Clear Lock
Check Locust - all is well

AHHHHH

Emergency branch and update

Show what changed in github compare/diff

git checkout v1.0.1

docker-compose up -d demo-api-v101

docker-compose logs -f demo-api
docker-compose logs -f demo-api-v101

git checkout v2.0.0
make db-upgrade

FAIL FAIL FAIL AGAIN!

Check pgadmin
Check Locust - FAIL FAIL
Clear Lock in pgAdmin
Check Locust - all is well

docker-compose stop demo-api

These next two commands won't work:

make db-upgrade
docker-compose exec --env FLASK\_APP=demo demo-api flask db upgrade --directory /mnt/migrations

BECAUSE V2.0.0 DOES NOT KNOW ABOUT V1.0.1!

docker-compose up -d demo-api-v2 make db-upgrade

FINALLY

Check pgadmin:

select * from users
where id < 51;

No last names?! OK, no, we haven't rolled out any front end changes. Stop and reload locust (as if we deployed the front-end updates to users):

make perftest

Check the nginx.conf - try a canary deployment?

cp nginx/nginx-v2-canary.conf ./nginx.conf

docker-compose logs -f demo-api-v2
docker-compose logs -f demo-api-v101

make reload\_nginx

SHOULD see slow logs and fast logs

Check for uptime then fully deploy

cp nginx/ngix-v2.conf ./nginx.conf

Yay, v2 is released!

select * from users

OH NO!!!! DATA CORRUPTION!!

Names don't match first + last names! The Horror!

Compare v2.0.1 in github compare/diff

git checkout v2.0.1

docker-compose up -d demo-api-v201
docker-compose logs -f demo-api-v201

cat nginx.conf

make nginx\_reload

SQL Scripts for somewhere along the way...

Note that these are useless if ran at the wrong time (that's why they're sneaky here at the end).

Too soon and users just overwrite things with bad data. Too late and users have overwritten things with worse data (in our case).

set name = first || ' ' || last
where name != first || ' ' || last;

update users
set first = split\_part(name, ' ', 1),
	last = split\_part(name, ' ', 2)
where first is null;

select *
from users
where
first != split\_part(name, ' ', 1) or
	name is null or
	first is null;

Tear it all down...

docker-compose down --remove-orphans

chipmonkey/deploydemo