Custom Instrumentation
To capture transactions and spans customized to your organization's needs, you must first set up performance monitoring.
To instrument certain regions of your code, you can create transactions to capture them.
The following example creates a transaction for a scope that contains an expensive operation (for example, process_item
), and sends the result to Sentry:
# start a transaction
transaction = Sentry.start_transaction(op: "process_item")
# perform the operation
process_item(args)
# finish the transaction, which will send it to Sentry automatically
transaction.finish
The next example contains the implementation of the hypothetical process_item
function called from the code snippet in the previous section. Our SDK can determine if there is currently an open transaction and add all newly created spans as child operations to that transaction. Keep in mind that each individual span also needs to be manually finished; otherwise, spans will not show up in the transaction. When using spans and transactions as context managers, they are automatically finished at the end of the with
block.
You can choose the values of op
and description
.
class OrdersController < ApplicationController
def create
order = Order.new
Sentry.with_child_span(op: :process_items, description: "") do |span|
span.set_data(:key, "value")
order.process_items(params)
end
end
end
Your new span will be nested under whichever span is currently running, otherwise it will be at the root of the transaction event.
Alternatively, you can manually grab the current transaction and use its with_child_span
method to always create a top-level span.
class OrdersController < ApplicationController
def create
order = Order.new
transaction = Sentry.get_current_scope.get_transaction
transaction.with_child_span(op: :process_items, description: "process order's items") do |span|
span.set_data(:key, "value")
order.process_items(params)
end # the child span ends with the block
end
end
Keep in mind that there may not be an active transaction, in which case get_transaction
returns nil
. This case needs to be handled manually and is missing from this example.
In cases where you want to attach Spans to an already ongoing Transaction you can use Sentry.get_current_scope.get_transaction
. This property will return a Transaction
in case there is a running Transaction otherwise it returns nil
.
transaction = Sentry.get_current_scope.get_transaction || Sentry.start_transaction(name: "task")
span = transaction.start_child(op: "operation")
# perform the operation
Started spans are stored in the scope, and can be fetched off the scope:
span = Sentry.get_current_scope.get_span
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").
- Package:
- gem:sentry-rails
- Version:
- 5.17.3
- Repository:
- https://github.com/getsentry/sentry-ruby