15.5. Transformation Function Overview

The provided transformation functions are listed below.

15.5.1. Control Functions

  • try

15.5.2. String Functions

  • stripQuotes
  • length
  • trim
  • capitalize
  • lowercase
  • regexReplace
  • concatenate
  • substring
  • toString

15.5.3. Date Functions

  • now
  • date
  • dateTime
  • basicDate
  • basicDateTime
  • basicDateTimeNoMillis
  • dateHourMinuteSecondMillis
  • millisToDate
  • secsToDate

15.5.4. Geometry Functions

  • point
  • linestring
  • polygon
  • geometry

15.5.5. ID Functions

  • stringToBytes
  • md5
  • uuid
  • base64

15.5.6. Type Conversions

  • ::int or ::integer
  • ::long
  • ::float
  • ::double
  • ::boolean
  • ::r
  • stringToInt or stringToInteger
  • stringToLong
  • stringToFloat
  • stringToDouble
  • stringToBoolean

15.5.7. List and Map Parsing

  • parseList
  • parseMap

15.5.8. Functions defined using scripting languages

You can define functions using scripting languages that support JSR-223. This is currently tested with JavaScript only as it is natively supported in all JREs via the Nashorn extension. To define a JavaScript function for use in the converter framework, create a file with the .js extension and the function definition as the contents of the file. For instance, if you have defined a function such as

function hello(s) {
   return "hello: " + s;
}

you can reference that function in a transform expression as js:hello($2)

15.5.9. Installing Custom Scripts

Custom scripting functions are made available to GeoMesa comamnd line tools or distributed (mapreduce) ingest via including them on the classpath or setting a system property.

For local usage, geomesa defines the system property geomesa.convert.scripts.path to be a colon-separated list of script files and/or directories containing scripts. This system property can be set when using the command line tools by setting the CUSTOM_JAVA_OPTS environmental variable:

CUSTOM_JAVA_OPTS="/path/to/script.js:/path/to/script-dir/"

A more resilient method of including custom scripts is to package them as a JAR or ZIP file and add it to the GEOMESA_EXTRA_CLASSPATHS environmental variable. If using maven you can simply package them in a folder under src/main/resources/geomesa-convert-scripts/ which will create a folder in your jar file named geomesa-convert-scripts with the scripts inside. You can manually create a jar with this folder as well. An easier way is often to package them as a zip archive with a folder similary named geomesa-convert-scripts inside the archive containing the scripts:

$ unzip -l /tmp/scripts.zip
Archive:  /tmp/scripts.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2017-03-09 11:33   geomesa-convert-scripts/
       42  2017-03-09 11:33   geomesa-convert-scripts/my-script.js
---------                     -------
       42                     2 files

For either zip or jar files add them to the extra classpaths in your environment to make them available for the tools or mapreduce ingest:

GEOMESA_EXTRA_CLASSPATHS="/path/to/my-scripts.jar:/tmp/scripts.zip"

A example of ingest with a scripts on the classpath is below:

GEOMESA_EXTRA_CLASSPATHS="/tmp/scripts.zip:/path/to/my-scripts.jar" bin/geomesa ingest -u <user-name>
-p <password> -s <sft-name> -C <converter-name> -c geomesa.catalog hdfs://localhost:9000/data/example.csv

You can also verify the classpath is properly configured with the tools:

GEOMESA_EXTRA_CLASSPATHS="/tmp/scripts.zip:/path/to/my-scripts.jar" bin/geomesa classpath

15.5.10. CQL Functions

Most of the basic CQL functions are available as transformations. To use one, invoke it like a regular function, prefixed with the cql namespace. For example, you can use the CQL buffer function to turn a point into a polygon:

cql:buffer($1, 2.0)

For more information on the various CQL functions, see the GeoServer filter function reference.

15.5.11. JSON/Avro Transformations

See Parsing Json and Parsing Avro sections