As of release 1.1.0, Telegraf has the concept of Aggregator and Processor Plugins.
These plugins sit in-between Input & Output plugins, aggregating and processing metrics as they pass through Telegraf:
┌───────────┐
│ │
│ CPU │───┐
│ │ │
└───────────┘ │
│
┌───────────┐ │ ┌───────────┐
│ │ │ │ │
│ Memory │───┤ ┌──▶│ InfluxDB │
│ │ │ │ │ │
└───────────┘ │ ┌─────────────┐ ┌─────────────┐ │ └───────────┘
│ │ │ │Aggregate │ │
┌───────────┐ │ │Process │ │ - mean │ │ ┌───────────┐
│ │ │ │ - transform │ │ - quantiles │ │ │ │
│ MySQL │───┼───▶│ - decorate │────▶│ - min/max │───┼──▶│ File │
│ │ │ │ - filter │ │ - count │ │ │ │
└───────────┘ │ │ │ │ │ │ └───────────┘
│ └─────────────┘ └─────────────┘ │
┌───────────┐ │ │ ┌───────────┐
│ │ │ │ │ │
│ SNMP │───┤ └──▶│ Kafka │
│ │ │ │ │
└───────────┘ │ └───────────┘
│
┌───────────┐ │
│ │ │
│ Docker │───┘
│ │
└───────────┘
Both Aggregators and Processors analyze metrics as they pass through Telegraf.
Use measurement filtering to control which metrics are passed through a processor or aggregator. If a metric is filtered out the metric bypasses the plugin and is passed downstream to the next plugin.
Processor plugins process metrics as they pass through and immediately emit results based on the values they process. For example, this could be printing all metrics or adding a tag to all metrics that pass through.
Aggregator plugins, on the other hand, are a bit more complicated. Aggregators
are typically for emitting new aggregate metrics, such as a running mean,
minimum, maximum, or standard deviation. For this reason, all aggregator
plugins are configured with a period
. The period
is the size of the window
of metrics that each aggregate represents. In other words, the emitted
aggregate metric will be the aggregated value of the past period
seconds.
Since many users will only care about their aggregates and not every single metric
gathered, there is also a drop_original
argument, which tells Telegraf to only
emit the aggregates and not the original metrics.
Since aggregates are created for each measurement, field, and unique tag combination
the plugin receives, you can make use of taginclude
to group
aggregates by specific tags only.
NOTE That since aggregators only aggregate metrics within their period, that
historical data is not supported. In other words, if your metric timestamp is more
than now() - period
in the past, it will not be aggregated. If this is a feature
that you need, please comment on this github issue