Phx Chat

A chat application built with:

• Phoenix Live View
• PostgreSQL (via Google Cloud SQL)
• Redis
• Kubernetes
• Docker
• CircleCI for testing, building images, and deployment to the Kubernetes cluster.

The production app runs multiple webapp pods each with a cloud proxy sidecar container to connect to the GCP Cloud SQL Postgres database.

A makeover of echat, now with needless farkles and absurd infrastructure.

Notes and other information

See below for various development and deployment notes.

TODO LIST

• Break readme into sub files

CircleCI

to encode the kubernetes config file:

cat /path/to/kubeconfig.yaml | base64 -w 0

(-w 0 ensures the output is one long string)

Then set that in CircleCI as KUBECONFIG_DATA

Heroku

Maintenance

heroku maintenance:on or heroku maintenance:off

Scale Down

heroku ps:scale web=0

Status

heroku ps

Releases

heroku releases

Bash in

heroku run bash

Logs

heroku logs --tail

(if needed can be dyno specific or w/e)

mix release

for a prod build:

(1) build, compile, etc. as normal.

(2) updated prod secret confix to be runtime release, and update config to start phoenix endpoint (no mix phx.server to do it for us)

See these sources:

https://hexdocs.pm/phoenix/releases.html https://hexdocs.pm/mix/1.9.4/Mix.Tasks.Release.html

mix release

* assembling phx_chat-0.1.0 on MIX_ENV=prod
importing prod.exs...
* using config/releases.exs to configure the release at runtime
* skipping elixir.bat for windows (bin/elixir.bat not found in the Elixir installation)
* skipping iex.bat for windows (bin/iex.bat not found in the Elixir installation)

Release created at _build/prod/rel/phx_chat!

    # To start your system
    _build/prod/rel/phx_chat/bin/phx_chat start

Once the release is running:

    # To connect to it remotely
    _build/prod/rel/phx_chat/bin/phx_chat remote

    # To stop it gracefully (you may also send SIGINT/SIGTERM)
    _build/prod/rel/phx_chat/bin/phx_chat stop

To list all commands:

    _build/prod/rel/phx_chat/bin/phx_chat

Postgres connection

Execute psql in the running postgres container

docker exec -it phx_chat_postgres_1 psql -U postgres

create the expected database

postgres=# CREATE DATABASE phx_chat_dev;
CREATE DATABASE

For test:

postgres=# CREATE DATABASE phx_chat_test;
CREATE DATABASE

Sees the database

phx_chat_dev=# \l
                                  List of databases
     Name     |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges
--------------+----------+----------+------------+------------+-----------------------
 phx_chat_dev | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 postgres     | postgres | UTF8     | en_US.utf8 | en_US.utf8 |
 template0    | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
              |          |          |            |            | postgres=CTc/postgres
 template1    | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
              |          |          |            |            | postgres=CTc/postgres

Connect to that db

postgres=# \c phx_chat_dev
You are now connected to database "phx_chat_dev" as user "postgres".
phx_chat_dev=# select * from messages;
 id | message | inserted_at | updated_at
----+---------+-------------+------------
(0 rows)

phx_chat_dev=# \dt
               List of relations
 Schema |       Name        | Type  |  Owner
--------+-------------------+-------+----------
 public | messages          | table | postgres
 public | schema_migrations | table | postgres
(2 rows)

Migrations

Create with context

(preferred)

mix phx.gen.context Chat Message messages user:string message:string

Create a migration

mix ecto.gen.migration add_messages_table

Run a migration

mix ecto.migrate

Roll back a migration

mix ecto.rollback --step 1

Generators

Messages Context

mix phx.gen.context Chat Message messages user:string message:string

Seed Messages

(1) Ensure the database has been created via psql or otherwise

(2) In the chat container, execute:

mix run priv/repo/seeds.exs

Format

dbash chat
mix format mix.exs "lib/**/*.{ex,exs}" "test/**/*.{ex,exs}"

Heroku Deployment

Followed steps from [https://hexdocs.pm/phoenix/heroku.html](This Guide)

heroku create eqmvii-phx-chat --buildpack hashnuke/elixir

touch elixir_buildpack.config

heroku buildpacks:add https://github.com/gjaldon/heroku-buildpack-phoenix-static.git

touch phoenix_static_buildpack.config

Run Migrations

heroku run mix ecto.migrate

DB creation

heroku addons:create heroku-postgresql:hobby-dev

NOTE: This was initially 18, which caused the app to be boxed out when trying to run a pod locally NOTE TO FUTURE SELF: It's going to have to be even lower if you want to run multiple pods locally + run in the cloud

heroku config:set POOL_SIZE=9

Redis

Heroku Redis added manually via Web UI

heroku config:set PHOENIX_REDIS_URI="[REDACTED]"

(may need to revisit -- how to make unique for multiple servers?)

Secret Key Base

heroku config:set SECRET_KEY_BASE="[REDACTED]"

Testing

bash into the container (dbash chat), then mix test

= = = = = = = = = = = = = = = = = = = = = = = =

Phoenix Boilerplate:

PhxChat

To start your Phoenix server:

• Setup the project with mix setup
• Start Phoenix endpoint with mix phx.server

Now you can visit localhost:4000 from your browser.

Ready to run in production? Please check our deployment guides.

Learn more

• Official website: https://www.phoenixframework.org/
• Guides: https://hexdocs.pm/phoenix/overview.html
• Docs: https://hexdocs.pm/phoenix
• Forum: https://elixirforum.com/c/phoenix-forum
• Source: https://github.com/phoenixframework/phoenix