Error Log

Goose can optionally log details about all load test errors to a file. To enable, add the --error-log=<error.log> command line option, where <error.log> is either a relative or absolute path of the log file to create. Any existing file that may already exist will be overwritten.

The log holds two kinds of entries:

• a request error: the entire GooseErrorMetric object, created any time a request results in an error, including a request the load test marks as failed with set_failure;
• a transaction error: a GooseTransactionErrorMetric, created each time a transaction returns an error that is not already a request error: a TransactionError::Custom or Url, or a Reqwest error from reading the response body or building the request. A transaction that fails because one of its requests failed, as with set_failure, gets no entry of its own: the request error has one. It has elapsed, scenario_index, scenario_name (the machine name, as in the request log), transaction_index, transaction_name, run_time, user and error, the error as its Display writes it. Errors from test_start and test_stop are not logged.

The raw.headers field of a request error follows the same rule as in the request log: it lists only the headers set on the individual request.

Log Format

By default, logs are written in JSON Lines format. For example:

{"elapsed":0,"scenario_index":0,"scenario_name":"erruser","transaction_index":2,"transaction_name":"flaky","run_time":0,"user":0,"error":"TransactionError: custom error (every third call fails)"}
{"elapsed":0,"raw":{"method":"Get","url":"http://127.0.0.1:8080/about/","headers":[],"body":"","custom_method":""},"name":"/about/","final_url":"http://127.0.0.1:8080/about/","redirected":false,"response_time":0,"status_code":404,"user":0,"error":"404 Not Found: /about/"}

These lines are from a load test run against a local server that answers /about/ with a 404. Its ErrUser scenario requests / and /about/, and its flaky transaction returns TransactionError::Custom("every third call fails") one time in three. The first line is a transaction error, the second a request error.

The --error-format option can be used to change the log format to csv, json (default), raw or pretty format. The raw format is Rust’s debug output of the entire GooseErrorMetric or GooseTransactionErrorMetric object, one per line, and pretty is the same output spread over several indented lines per error.

The csv format starts with a header row. Its first nine columns are a request error’s fields, and its raw column holds the debug output of the GooseRawRequest. The last five columns, scenario_index, scenario_name, transaction_index, transaction_name and run_time, are a transaction error’s. A transaction error fills elapsed, user, error and those five, leaving the other request columns empty, and a request error leaves the last five empty, so every row has every column:

elapsed,raw,name,final_url,redirected,response_time,status_code,user,error,scenario_index,scenario_name,transaction_index,transaction_name,run_time
0,,,,,,,0,TransactionError: custom error (every third call fails),0,erruser,2,flaky,0
0,"GooseRawRequest { method: Get, url: ""http://127.0.0.1:8080/about/"", headers: [], body: """", custom_method: """" }",/about/,http://127.0.0.1:8080/about/,false,0,404,0,404 Not Found: /about/,,,,,

--no-error-summary leaves errors out of the errors tables of the metrics and reports, not out of this log.