Observability

Deno Deploy^EA provides multiple observability features that can be used to understand application performance, debug application errors, and monitor application usage. These features are based on OpenTelemetry and the OpenTelemetry integration in Deno.

There are three main observability features in Deno Deploy^EA:

• Logs: unstructured debug information captured emitted by the application code.
• Traces: structured information about the handling of a request, including time taken for each step, and automatic capturing of outbound I/O through the likes of fetch.
• Metrics: structured, high level data about application performance and usage, such as request count, error count, and latency.

Logs Jump to heading#

Logs in Deno Deploy^EA are captured using the standard console API. The logs are queryable from the logs page in the Deno Deploy ^EA dashboard.

Logs are viewed per application. The search bar on the logs page can be used to filter based on the attributes below, and the log message.

Logs are associated with a specific trace and span if they are emitted inside the context of a trace. For logs that have an associated trace, a "View trace" button is shown in the logs page. This will open the relevant trace in an overlay drawer for inspection.

Traces Jump to heading#

Traces in Deno Deploy^EA are captured in three ways:

• Automatically for various built-in operations, such as incoming HTTP requests or outbound fetch. This can not be disabled.
• Automatically for some frameworks, such as Next.js, Fresh, and Astro. The exact set of frameworks and instrumented operations is subject to change.
• Manually when application code creates a new trace or span using the OpenTelemetry API. This requires manual instrumentation of the application code.

Traces are viewed per application. The search bar on the trace page can be used to filter based on the attributes below, and the span name.

Clicking on a trace will open the trace overlay drawer, which shows all spans that are part of the trace. The spans are shown in a waterfall view, which shows the start and end time of each span, as well as the duration of each span. The spans are grouped by their parent span, and the root span is shown at the top of the waterfall view.

Clicking on any span will open the span details at the bottom of the drawer. Captured span attributes are shown in a table here. For outbound HTTP requests for example, this contains the HTTP method, URL, and status code.

In addition to the span attributes, the span details section also has a "Logs" tab that shows all logs that were emitted in the context of the span.

Clicking on the "View logs" on the right of any trace will open the logs page with the trace ID pre-filled in the search bar. This will show all logs that were emitted in the context of the entire trace.

Metrics Jump to heading#

Metrics in Deno Deploy^EA are captured automatically for various built-in operations, such as incoming HTTP requests or outbound fetch. This can not be disabled.

Metrics are viewed per application. The search bar on the metrics page can be used to filter based on the attributes below. Metrics are shown in a time series graph, which shows the value of the metric over time.

Filtering Jump to heading#

Logs, traces, and metrics can be filtered by general attributes:

• Revision: the ID of the application's revision that emitted the log, trace, or metric.

• Context: the context in which the log, trace, or metric was emitted. This can be either "Production" or "Development".

For logs and traces, the following additional filter is available:

• Trace: the ID of the trace that contained the log or spans.

For traces only, the following additional filter is available:

• HTTP Method: the HTTP method of the request that triggered the trace.

• HTTP Path: the path of the request that triggered the trace.

• HTTP Status: the HTTP status code of the response that was sent for the request that triggered the trace.

Time range filter Jump to heading#

By default, the logs, traces, and metrics pages show data for the last hour. This can be changed using the time range filter in the top right corner of the page. The time range filter can be set to a predefined time range, like "Last 1 hour", "Last 24 hours", or "Last 7 days", or a custom time range.

The custom time range can be set by clicking on the "Custom" button. A custom time range can either be absolute (a specific start and end time) or relative (3 days ago, 1 hour from now, etc.). The time range filter is shown in the top right corner of the page.

Relative time ranges use the same syntax as Grafana, where now is the current time, and now-1h is 1 hour ago. Furthermore syntax such as now-1h/h can be used to round the time to the nearest hour. Some examples:

• now-1h - 1 hour ago
• now/h - the start of the current hour
• now-1h/h - the start of the previous hour
• now/d+3h - 3 hours from the start of the current day
• now-1d/d - the start of the previous day