docs
| id | page | ref | title | content | breadcrumbs | references |
|---|---|---|---|---|---|---|
| internals:internals-tracer | internals | internals-tracer | datasette.tracer | Running Datasette with --setting trace_debug 1 enables trace debug output, which can then be viewed by adding ?_trace=1 to the query string for any page. You can see an example of this at the bottom of latest.datasette.io/fixtures/facetable?_trace=1 . The JSON output shows full details of every SQL query that was executed to generate the page. The datasette-pretty-traces plugin can be installed to provide a more readable display of this information. You can see a demo of that here . You can add your own custom traces to the JSON output using the trace() context manager. This takes a string that identifies the type of trace being recorded, and records any keyword arguments as additional JSON keys on the resulting trace object. The start and end time, duration and a traceback of where the trace was executed will be automatically attached to the JSON object. This example uses trace to record the start, end and duration of any HTTP GET requests made using the function: from datasette.tracer import trace import httpx async def fetch_url(url): with trace("fetch-url", url=url): async with httpx.AsyncClient() as client: return await client.get(url) | ["Internals for plugins"] | [{"href": "https://latest.datasette.io/fixtures/facetable?_trace=1", "label": "latest.datasette.io/fixtures/facetable?_trace=1"}, {"href": "https://datasette.io/plugins/datasette-pretty-traces", "label": "datasette-pretty-traces"}, {"href": "https://latest-with-plugins.datasette.io/github/commits?_trace=1", "label": "a demo of that here"}] |