🌲 Timber - Great Elixir Logging Made Easy
Timber for Elixir is a drop in backend for the Elixir Logger
that
unobtrusively augments your
logs with rich metadata and context
making them easier to search, use, and read. It pairs with the
Timber console to deliver a tailored Elixir logging experience designed to make
you more productive.
- Installation - One command:
mix timber.install
- Usage - Simple yet powerful API
- Integrations - Automatic context and metadata for your existing logs
- The Timber Console - Designed for Elixir developers
- Get things done with your logs 💪
Installation
Add
timber
as a dependency inmix.exs
:# Mix.exs def application do [applications: [:timber]] end def deps do [{:timber, "~> 2.1"}] end
In your
shell
, runmix deps.get && mix timber.install
.
Usage
Basic text logging
The Timber library works directly with the standard Elixir [Logger](https://hexdocs.pm/logger/Logger.html) and installs itself as a [backend](https://hexdocs.pm/logger/Logger.html#module-backends) during the setup process. In this way, basic logging is no different than logging without Timber: ```elixir Logger.debug("My log statement") Logger.info("My log statement") Logger.warn("My log statement") Logger.error("My log statement") ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `error message` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this event's metadata and context](https://timber.io/docs/app/console/view-metadata-and-context) [...read more in our docs](https://timber.io/docs/languages/elixir/usage/basic-logging) ---
Logging events (structured data)
Log structured data without sacrificing readability: ```elixir event_data = %{customer_id: "xiaus1934", amount: 1900, currency: "USD"} Logger.info("Payment rejected", event: %{payment_rejected: event_data}) ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `type:payment_rejected` or `payment_rejected.amount:>100` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this event's data and context](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/custom-events) ---
Setting context
Add shared structured data across your logs: ```elixir Timber.add_context(build: %{version: "1.0.0"}) Logger.info("My log message") ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `job.id:123` * [View this context when viewing a log's metadata](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/custom-context) ---
Timings & Metrics
Time code blocks: ```elixir timer = Timber.start_timer() # ... code to time ... Logger.info("Processed background job", event: %{background_job: %{time_ms: timer}}) ``` Log generic metrics: ```elixir Logger.info("Processed background job", event: %{background_job: %{time_ms: 45.6}}) ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `background_job.time_ms:>500` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this log's metadata in the console](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/metrics-and-timings) ---
Tracking background jobs
*Note: This tip refers to traditional background jobs backed by a queue. For native Elixir processes we capture the `context.runtime.vm_pid` automatically. Calls like `spawn/1` and [`Task.async/1`](https://hexdocs.pm/elixir/Task.html#async/1) will automatially have their `pid` included in the context.* For traditional background jobs backed by a queue you'll want to capture relevant job context. This allows you to segement logs by specific jobs, making it easy to debug and monitor your job executions. The most important attribute to capture is the `id`: ```elixir %Timber.Contexts.JobContext{queue_name: "my_queue", id: "abcd1234", attempt: 1} |> Timber.add_context() Logger.info("Background job execution started") # ... Logger.info("Background job execution completed") ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `background_job.time_ms:>500` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this log's metadata in the console](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/tracking-background-jobs) ---
Track communication with external services
We use this trick internally at Timber to track communication with external services. It logs requests and responses to external services, giving us insight into response times and failed requests. Below is a contrived example of submitting an invoice to Stripe. ```elixir alias Timber.Events.HTTPRequestEvent alias Timber.Events.HTTPResponseEvent method = :get url = "https://api.stripe.com/v1/invoices" body = "{\"customer\": \"cus_BHhZyYRirFrPkz\"}" headers = %{} Logger.info fn -> event = HTTPRequestEvent.new(direction: "outgoing", service_name: "stripe", method: method, url: url, headers: headers, body: body) message = HTTPRequestEvent.message(event) {message, [event: event]} end case :hackney.request(method, url, headers, body, with_body: true) do {:ok, status, resp_headers, resp_body} -> Logger.info fn -> event = HTTPResponseEvent.new(direction: "incoming", service_name: "stripe", status: status, headers: resp_headers, body: resp_body) message = HTTPResponseEvent.message(event) {message, [event: event]} end {:error, error} -> message = Exception.message(error) Logger.error(message, event: error) {:error, error} end ``` *Note: Only `method` is required for `HTTPRequestEvent`, and `status` for `HTTPResponseEvent`. `body`, if logged, will be truncated to `2048` bytes for efficiency reasons. This can be adjusted with [`Timber.Config.http_body_size_limit/0`](https://hexdocs.pm/timber/Timber.Config.html#http_body_size_limit/0).* * [Search it](https://timber.io/docs/app/console/searching) with queries like: `background_job.time_ms:>500` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this log's metadata in the console](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/track-external-service-communication) ---
Adding metadata to errors
By default, Timber will capture and structure all of your errors and exceptions, there is nothing additional you need to do. You'll get the exception `message`, `name`, and `backtrace`. But, in many cases you need additional context and data. Timber supports additional fields in your exceptions, simply add fields as you would any other struct. ```elixir defmodule StripeCommunicationError do defexception [:message, :customer_id, :card_token, :stripe_response] end raise( StripeCommunicationError, message: "Bad response #{response} from Stripe!", customer_id: "xiaus1934", card_token: "mwe42f64", stripe_response: response_body ) ``` * [Search it](https://timber.io/docs/app/console/searching) with queries like: `background_job.time_ms:>500` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this log's metadata in the console](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/adding-metadata-to-errors) ---
Sharing context between processes
The [`Timber.Context`](Timber.Context.html) is local to each process, this is by design as it prevents processes from conflicting with each other as they maintain their contexts. But many times you'll want to share context between processes because they are related (such as processes created by [`Task`](https://hexdocs.pm/elixir/Task.html) or `Flow`). In these instances copying the context is easy. ```elixir current_context = Timber.CurrentContext.load() Task.async fn -> Timber.CurrentContext.save(current_context) Logger.info("Logs from a separate process") end ``` `current_context` in the above example is captured in the parent process, and because Elixir's variable scope is lexical, you can pass the referenced context into the newly created process. [`Timber.CurrentContext.save/1`](Timber.CurrentContext.html#save/1) copies that context into the new process dictionary. * [Search it](https://timber.io/docs/app/console/searching) with queries like: `background_job.time_ms:>500` * [Alert on it](https://timber.io/docs/app/console/alerts) with threshold based alerts * [View this log's metadata in the console](https://timber.io/docs/app/console/view-metadata-and-context) ...[read more in our docs](https://timber.io/docs/languages/elixir/usage/sharing-context-between-processes) ---
Capture user context
Capturing `user context` is a powerful feature that allows you to associate logs with users in your application. This is great for support as you can [quickly narrow logs to a specific user](https://timber.io/docs/app/console/tail-a-user), making it easy to identify user reported issues. ### How to use it Simply add the `UserContext` immediately after you authenticate the user: ```elixir %Timber.Contexts.UserContext{id: "my_user_id", name: "John Doe", email: "john@doe.com"} |> Timber.add_context() ``` All of the `UserContext` attributes are optional, but at least one much be supplied.
Only log slow Ecto SQL queries
Logging SQL queries can be useful but noisy. To reduce the volume of SQL queries you can limit your logging to queries that surpass an execution time threshold: ### How to use it ```elixir config :timber, Timber.Integrations.EctoLogger, query_time_ms_threshold: 2_000 # 2 seconds ``` In the above example, only queries that exceed 2 seconds in execution time will be logged.