Timeshift influxDB proxy with Mathematics across measurements feature

This proxy server will add timeshift feature to you influxDB server. This feature is extremely helpful to compare periods in Grafana.

Proxy can to mathematical operations between queries (i.e. between metrics).

Installation

Node.js version 6 or later is required to run the code.

We assume that InfluxDB in available on 192.168.33.11:8086

git clone https://github.com/maxsivanov/influxdb-timeshift-proxy.git
cd influxdb-timeshift-proxy
npm i
INFLUXDB=192.168.33.11:8086 npm run start

OR

npm i influxdb-timeshift-proxy -g
INFLUXDB=192.168.33.11:8086 influxdb-timeshift-proxy

On Windows you need other command to run proxy

setx INFLUXDB 192.168.33.11:8086
influxdb-timeshift-proxy

Proxy will be available on port 8089.

It is possible to use already proxied InfluxDB.

INFLUXDB=http://my.host.lan/api/datasources/proxy/19 npm run start

Proxying of Proxied :) feature is not very stable yet. Sometimes proxy will fail with HTTP 500. Waiting for this bug in express-http-proxy to fix. Anyway direct connection i.e INFLUXDB=192.168.33.11:8086 npm run start works fine.

Usage

Proxy will go timeshift on queries with fields listed with alias AS "shift_1_weeks". 1 can be any positive integer number. weeks can be any unit described here https://momentjs.com/docs/#/manipulating/add/.

You can use MATH query to do mathematical operation between previously defined queries.

• name and expr attributes are mandatory.
• You can use any mathematical operation in expr: +, -, *, /, %.
• $0, $1 ... etc are indexes of query results to be used in expression.
• Infinity and NaN results will be converted to null, so do not be afraid of division by zero.
• MATH will clear returned values from query results used for mathematical operation. Use keep attribute to keep source data.
• Use singlestat attribute if you want to use MATH in Singlestat panels.

Example requests

Shift one week back:

SELECT non_negative_derivative("value", 1h) AS "shift_1_weeks" FROM "CPU_LOAD" WHERE "tag" = 'all' 

Shift two days back:

SELECT non_negative_derivative("value", 1h) AS "shift_2_days" FROM "CPU_LOAD" WHERE "tag" = 'all' 

Sum two metrics and clear source metrics from result

MATH name="ALL" expr="$0 + $1"

Sum two metrics and keep source metrics in result

MATH name="ALL" expr="$0 + $1" keep="$0,$1"

Sum two metrics for singlestat panel

MATH name="ALL" expr="$0 + $1" singlestat

Debugging

Run proxy with DEBUG environment variable set:

• query -- display all queries
• rewrite -- display all query rewrites
• math -- display all MATH calculations are made