access global config in plugins

[yuankui]

Is any way to access global config like interval in plugins?

[sparrc]

yep: https://github.com/influxdata/telegraf#plugin-options

[zstyblik]

The way I understood the question is whether it's possible to access:

[agent]
  interval = 10s

from the plugin and not whether it's possible to configure different interval per plugin.

[sparrc]

@zstyblik please read the link above, it describes how to set the interval per-plugin

[zstyblik]

@sparrc - I understand your reply. I know you can set interval per plugin. And I'm telling you that's not how I understood the question. But I'm not the one whom asked and perhaps it's me who misunderstood the question. Still, if you have time, please, read again what I've written, resp. compare the last sentence and your reply. :)

[sparrc]

I don't see any reason plugins need access to the global interval parameter. Asking for a feature without giving the use-case usually leads to confusion ;-)

[zstyblik]

Sure. Use-case that comes to my mind could be choosing retention policy, resp. embedding interval into metric name in order to choose retention policy later up in the chain. And what not. I don't know. Anyway ...

[sparrc]

Why not just add a tag then? This would be a pretty minor duplication...

[agent]
  interval = "10s"

[tags]
  interval = "10s"

[zstyblik]

@sparrc sure, that could work, although it's hard to say what @yuankui 's use case is. Such thing wouldn't work for me. I would need per plugin tag rather than a global one :)

[sparrc]

@zstyblik per-plugin tags are coming in 0.3.0, see #437 and https://github.com/influxdata/telegraf#version-030-beta

[yuankui]

thank @zstyblik for reply.
here is my use case.

I want to monitor the network flow rate(Bytes per second) of every network interface.

but the provided network provide only the accumulated network bytes.

It's suggested to use derivative in SQL, bug I failed to get it to work. (maybe there is some issue in the function)

So I decided to calculate my self.

so I need to get the current bytes and the last updated bytes, and calculate the data rate with

(now - last) / interval?

So I need to get the global interval setting.

Is the request reasonable?

Or is there any other elegant way?

[sparrc]

I wouldn't rely on interval for that, you should store the timestamp of the last gather.

[zstyblik]

@sparrc great!

@yuankui have you reported the bug with InfluxDB? As far as I can tell, the query works for me. Whether reported values are correct, that's another story(I haven't invested time into this). But I'd try to solve it outside of Telegraf.

SELECT DERIVATIVE(value, 10s) FROM testdb2."1s".wave