TowerDB

A Tower reporter that stores errors and exceptions in a PostgreSQL database using Ecto.

Warning

Not production ready. TowerDB is under active development and its API may still change. We use it in several applications at Mimiquate, but it hasn't yet reached the bar we'd consider production ready. Use it at your own risk.

Features we're waiting on before calling it production ready:

Performance test

Installation

Add tower_db to your list of dependencies in mix.exs:

def deps do
  [
    {:tower_db, "~> 0.9.0"}
  ]
end

Then fetch the dependencies:

mix deps.get

Setup

Add TowerDB to your Tower reporters:

# config/config.exs

config(
  :tower,
  :reporters,
  [
    # along any other possible reporters
    TowerDB
  ]
)

And configure :tower_db.

# config/runtime.exs

if config_env() == :prod do
  config :tower_db,
    enabled: true,
    repo: MyApp.Repo
end

TowerDB requires database tables to store error events. Generate an Ecto migration:

mix ecto.gen.migration add_tower_db

If you want to use a repo different from MyApp.Repo as its primary repo, specify it with the -r flag:

mix ecto.gen.migration add_tower_db -r MyApp.SecondaryRepo

Then add the following content to the generated migration file:

defmodule MyApp.Repo.Migrations.AddTowerDB do
  use Ecto.Migration

  def up, do: TowerDB.Migration.up(from: 0, to: 8)
  def down, do: TowerDB.Migration.down(from: 8, to: 0)
end

Run the migration:

mix ecto.migrate

Reporting

That's it. There's no extra source code needed to get reports in your database.

Tower will automatically report any errors (exceptions, throws or abnormal exits) occurring in your application. That includes errors in any plug call (including Phoenix), Oban jobs, async task or any other Elixir process.

You can also enable or disable the reporter at runtime:

TowerDB.disable()
TowerDB.enable()

Pruner

TowerDB can automatically delete old or excess events so storage stays bounded. It's enabled by default with the settings below; configure :pruner under :tower_db to change that:

# config/config.exs

# enabled with defaults (same as not setting :pruner at all)
config :tower_db, pruner: []

# enabled, overriding only the settings you name (the rest keep their defaults)
config :tower_db, pruner: [max_age: {30, :days}]

# disabled entirely
config :tower_db, pruner: false

Available settings, all optional:

key	meaning	default
`max_age`	how long an event is kept before deletion	`{90, :days}`
`max_size`	total events kept across all issues	`100_000`
`max_size_per_issue`	events kept per issue	`1_000`
`interval`	time between prune runs	`{30, :seconds}`
`batch_size`	max rows deleted per batch	`1_000`

max_age and interval are {amount, unit} tuples, with unit one of :seconds, :minutes, :hours, or :days.

max_age, max_size and max_size_per_issue accept :infinity to disable that specific check.

Each prune run deletes, in batches of batch_size:

events older than max_age (unless :infinity);
for each issue, the oldest events beyond max_size_per_issue (unless :infinity);
the oldest events beyond max_size overall (unless :infinity).

License

See LICENSE.