TowerWeb

A Phoenix LiveView dashboard for viewing and storing Tower events.

Overview

TowerWeb provides a web interface to monitor error events captured by Tower, and includes its own Ecto-backed reporter to persist those events to a PostgreSQL database — no separate storage package required.

Important

tower_db is being deprecated in favor of this built-in storage. If your app currently depends on tower_db, migrate to tower_web's own storage and remove the tower_db dependency — see Migrating from tower_db below. New installs should skip tower_db entirely.

Warning

Not production ready. TowerWeb is under active development. 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_web as a dependency in your mix.exs:

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

Setup

1. Configure the reporter

Register TowerWeb.DB as a Tower reporter, and point it at your application's Ecto repo:

config :tower, :reporters, [TowerWeb.DB]

# runtime.exs
config :tower_web,
  enabled: true,
  repo: MyApp.Repo,
  base_url: "https://myapp.com/errors"

2. Add and run the migration

Generate a migration:

mix ecto.gen.migration add_tower_web_db

Fill it with:

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

  def up, do: TowerWeb.DB.Migration.up(from: 0, to: 3)
  def down, do: TowerWeb.DB.Migration.down(from: 3, to: 0)
end

Then run:

mix ecto.migrate

3. Mount the dashboard

In your Phoenix router, import and mount the dashboard:

defmodule MyAppWeb.Router do
  use MyAppWeb, :router

  import TowerWeb.Router

  scope "/" do
    pipe_through :browser
    tower_dashboard "/tower"
  end
end

Migrating from tower_db

If your app already depends on the standalone tower_db package, move to tower_web's built-in storage instead of running both:

1. tower_web doesn't rename your existing tower_db_events table for you, so add a migration that does it yourself, generated before the one from Setup step 2 so it runs first:

   defmodule MyApp.Repo.Migrations.RenameTowerDbEvents do
     use Ecto.Migration
   
     def up, do: execute("ALTER TABLE IF EXISTS tower_db_events RENAME TO tower_web_events")
     def down, do: execute("ALTER TABLE IF EXISTS tower_web_events RENAME TO tower_db_events")
   end

   With tower_web_events already in place, the Setup migration becomes a no-op for the table itself (it only adds the extension and any missing indexes). Add both migrations, then run mix ecto.migrate once — Ecto applies pending migrations in timestamp order, so the rename runs before Setup's.

2. Replace TowerDB with TowerWeb.DB everywhere it's referenced in your app: config :tower, :reporters, [...], any config :tower_db, ... keys (move them to config :tower_web, ...), and any direct calls like TowerDB.Reporter.report_event/1.

3. Remove {:tower_db, ...} from your mix.exs deps.

Don't keep both tower_db and tower_web installed and enabled long-term — that leaves you with two independent tables (tower_db_events and tower_web_events) and two reporters that could both persist the same event. tower_db is going away; tower_web is the path forward.

Configuration

Pruner

TowerWeb periodically prunes old events so the table doesn't grow unbounded. Configure it with:

config :tower_web,
  pruner: [
    max_age: {90, :days},
    max_size: 100_000,
    max_size_per_issue: 1_000,
    interval: {30, :seconds},
    batch_size: 1_000
  ]

Set pruner: false to disable it entirely.

Burst protection

TowerWeb drops events once a configured rate is exceeded, protecting storage and the database from sudden error storms (e.g. a crash loop). It's always on; configure :burst_protection under :tower_web to change its settings:

# config/config.exs

config :tower_web, burst_protection: [max_count: 500, interval: 30]

Available settings, all optional:

key	meaning	default
max_count	events allowed per window before dropping	100
interval	length of each window, in seconds	10

Events beyond max_count are dropped until the window resets every interval seconds. A summary of dropped events, if any, is logged on reset.

Enable/disable at runtime

TowerWeb.DB.enable()
TowerWeb.DB.disable()

Usage

Start your Phoenix server and visit /tower to see the dashboard.

License

See LICENSE file.