/ Apr 21st, 2021 /

Introducing `vector tap`

Observing events flowing through your Vector topologies

Vector 0.13 introduces a new vector tap subcommand that allows for tapping into the events flowing through Vector. This can be used to "live tail" events while troubleshooting incidents events or simply to debug your Vector config, replacing the current common approach of sending the events to a console sink.

Get Started

To use vector tap you must first enable Vector's GraphQL API. Then, you can use vector tap <component name> to sample the events flowing out of this component.

For example, given the configuration:

[api]
enabled = true
[sources.in]
type = "generator"
format = "shuffle"
interval = 1.0
lines = ["Hello World"]
sequence = true
[sinks.out]
type = "blackhole"
inputs = ["in"]

If you were to run vector and then, in another terminal, run vector tap in, you would see something like:

{"message":"13 Hello World","timestamp":"2021-04-20T19:40:32.359390Z"}
{"message":"14 Hello World","timestamp":"2021-04-20T19:40:33.355298Z"}
{"message":"15 Hello World","timestamp":"2021-04-20T19:40:34.353215Z"}
{"message":"16 Hello World","timestamp":"2021-04-20T19:40:35.353493Z"}
{"message":"17 Hello World","timestamp":"2021-04-20T19:40:36.352089Z"}
{"message":"18 Hello World","timestamp":"2021-04-20T19:40:37.347406Z"}

With the events formatted as JSON.

API

Like vector top, this command is made possible by vector through its GraphQL API. You can interact directly with the API if you want to take advantage of tapping events programmatically.

Future Work

We intend to make the vector tap command even more powerful by:

  • Allowing sampling of metrics events
  • Allowing events to be formatted as logfmt rather than just JSON or YAML
  • Allowing sampling of events going into a component rather than out of it
  • Allowing tighter control over how events are sampled

Have an idea of how to make vector tap even more useful? Let us know.

This change was made available in 0.13.0. You can get this change by downloading the latest stable release.

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