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InfluxDB Fetcher

About

Use this program to fetch data from InfluxDB using the HTTP query API and export it into InfluxDB line protocol format.

Synopsis

influxdb-fetcher uri username password database query [fieldstotags]

Example

influxdb-fetcher \
    http://influxdb.example.org:8086 root root aqi_readings \
    "SELECT station_type, latitude, longitude, aqi_value FROM testdrive GROUP BY station_type LIMIT 100"

Setup

wget --no-clobber --output-document=/usr/local/bin/influxdb-fetcher https://raw.githubusercontent.com/hgomez/influxdb/master/bin/influxdb-fetcher
chmod +x /usr/local/bin/influxdb-fetcher

Advanced usage

Transform fields to tags

You could also transform fields into tags by adding them as a list of comma- separated labels as a last parameter to the command line.

The background of this is that since as of today, there is now way to transform fields into tags. See also: influxdata/influxdb#3904.

In the following example, latitude and longitude fields will be put as tags into the line protocol format output.

influxdb-fetcher \
    http://influxdb.example.org:8086 root root aqi_readings \
    "SELECT * FROM testdrive GROUP BY station_type LIMIT 100" \
    latitude,longitude

Rename fields

As the line protocol format is pure ASCII, it is easy to use standard Unix tools like sed to manipulate the content. For more advanced manipulations, we recommend to use Perl. Those are some examples which roughly outline the process.

# Fetch data.
influxdb-fetcher ... > data.lineproto

# Manipulate schema: Rename field.
sed -i -e "s/foo\=\([0-9.]*\)/bar=\1/g" data.lineproto

# Manipulate schema: Advanced field renaming with negative lookbehind.
# This renames all fields not already prefixed with `SonoffSC.`.
perl -pi -e "
  s/(?<!SonoffSC\.)AirQuality/SonoffSC\.AirQuality/; \
  s/(?<!SonoffSC\.)Humidity/SonoffSC\.Humidity/; \
  s/(?<!SonoffSC\.)Light/SonoffSC\.Light/; \
  s/(?<!SonoffSC\.)Noise/SonoffSC\.Noise/; \
  s/(?<!SonoffSC\.)Temperature/SonoffSC\.Temperature/; \
  " \
  data.lineproto

# Manipulate data: Cast from Int64 to Float.
sed -i -e "s/value\=\([0-9]*\)i/value=\1/g" data.lineproto

# Upload data to different destination.
curl -u login:password -i -POST \
  "http://dest-influxdb.example.org:8086/write?db=new_db" \
  --data-binary @data.lineproto

Notes

  • To get InfluxDB tags properly populated into line protocol format, you should add a GROUP BY clause.

  • By carefully crafting InfluxQL expressions (using WHERE time=...), you should be able to fetch data in batches, ideally 10K-20K at a time. This way you can extract chunks of the source data. The background of this is that InfluxDB will OOM with too large POST requests.

Development

Build code

cd influxdb-fetcher
mvn clean package