RestService

Running a REST Service

Newts provides a REST endpoint service based on the popular Dropwizard project.

Table of Contents

• Initialization
• Running
• Newts-specific configuration
  • Cassandra
    • All
  • Search
    • All
  • Reports
    • All
    • Datasources
    • Expressions
    • Exports
• See also

Initialization

A one-time initialization must be performed before starting the service for the first time; The init script accepts as it's only argument, a Newts config file, and when invoked creates all necessary Cassandra schema.

bin/init etc/config.yaml

Running

Running the bin/newts with no arguments outputs command synopsis.

bin/newts
Usage: java NewtsDaemon -c CFGFILE [-D] [-p PIDFILE] [-h]
  -D (--daemonize)      : Detach and run in the background
  -c (--config) CFGFILE : Path to configuration file (required).
  -h (--help)           : Print usage informations.
  -p (--pid) PIDFILE    : Path to PID file (default: newtsd.pid)

To run Newts in the foreground (the default):

bin/newts -c etc/config.yaml

To daemonize, and store the PID in /var/run/newts.pid:

bin/newts -D -p /var/run/newts.pid -f etc/config.yaml

Newts-specific configuration

Cassandra

cassandra:
  keyspace: newts
  host: localhost
  port:9042
  username: cassandra
  password: cassandra
  time-to-live: 31536000
  compression: none

All

Name	Default	Description
keyspace	newts	Cassandra keyspace name.
host	localhost	Hostname of Cassandra node/cluster.
port	9042	TCP port number of Cassandra node/cluster.
username	cassandra	Username used to connect to the Cassandra node/cluster.
password	cassandra	Password used to connect to the Cassandra node/cluster.
time-to-live	31536000	Seconds to expiration of Cassandra columns.
compression	none	Compression scheme to use for Cassandra queries. One of none, lzr, or snappy.

Search

search:
  enabled: true
  maxCacheEntries: 1000000
  hierarchical-indexing: true
  separatorEscaping: false

All

Name	Default	Description
enabled	false	Determines whether search indexing should be enabled.
maxCacheEntries	1000000	The number of previously indexed resources to maintain a cached state of (avoids unnecessary, redundant (re)indexing).
hierarchical-indexing	true	Indexes additional terms that allow the resource tree to be discovered. See NEWTS-57 for details.
separatorEscaping	false	Allows resource id separators (:) to be escaped using a backslash (:)

Reports

reports:
  temps:
    interval: 300s
    datasources:
      - label: inlet
        source: inletTemp
        function: AVERAGE
        heartbeat: 600s
      - label: outlet
        source: outletTemp
        function: AVERAGE
        heartbeat: 600s
    expressions:
      - label: diff
        expression: outlet - inlet
    exports:
      - inlet
      - outlet
      - diff

All

Name	Default	Description
interval	(none)	The expected sample interval. Intervals are specified as a numeric value followed by one of w, d, h, m, s, and ms (for weeks, days, hours, minutes, seconds, and millseconds respectively).

Datasources

Name	Default	Description
label	(none)	The name of the aggregated datasource.
source	(none)	Stored metric name.
function	(none)	Aggregate function (currently one of MIN, MAX, AVERAGE).
heartbeat	(none)	Upper bound on sample intervals; Values outside heartbeat yield a NaN during aggregation. Specified as a numeric value followed by one of w, d, h, m, s, and ms (for weeks, days, hours, minutes, seconds, and millseconds respectively).

Expressions

Name	Default	Description
label	(none)	Name of the expression result.
expression	(none)	The expression to evaluate.

Exports

Exports consist of a list of valid datasource and expression labels from the report scope that should be exported to the result set.

See also

The complete Dropwizard Configuration Reference.