sl2influx

SL2influx

Save current trafik data from Stockholm public transport (SL) to influxdb.

This program queries the SL real time traffic data API and saves the next arrival of each line to influxdb.

The program takes a few options

• -conf must be given and contains the configuration in YAML syntax
• -verbose prints out information on the program run
• -dryrun skips saving data to influxdb

Install

Prerequistes are of course an installation of the Go language https://golang.org/ and the following modules

• YAML https://gopkg.in/yaml.v2
• InfluxDB client https://github.com/influxdata/influxdb1-client

Configuration options

serverroot: http://api.sl.se/api2/realtimedeparturesV4.json
apikey: example-key
siteid: 1
sitedirection: 1
traveltype: 1

influxserver: http://127.0.0.1:8086
influxdb: SL
influxuser: SLuser
influxpasswd: SLpasswd

• serverroot is the URL of the real time traffic API (use the value provided)

• apikey You have to get your own API key at https://trafiklab.se

• siteid Trafiklab provides an API to find the siteid of the stop you want to monitor

• sitedirection is used to distinguish between side of the road for bus stops.

• traveltype is the type of transport to be saved (0=Metros,1=Buses,2=Trains,3=Trams,4=Ships)

• influxserver gives the URL to the influxdb server including port

• influxdb name of the database to save data to (must exist)

• influxuser username to access influxdb

• influxpasswd password to access influxdb

Influx

The database must be created before you start to save data. influx -execute 'create database "SL"'

All data is saved to a measurement called "SLlatest".

The measurement contains the following tags

• linenumber
• destination
• siteid
• sitedirection

and the following values

• TimeTableDateTime string in format YYYY-MM-DDTHH:MM:SS
• TimeTableTimestamp unix timestamp computed from TimeTableDateTime
• ExpectedDateTime strimg in format YYYY-MM-DDTHH:MM:SS
• ExpectedTimestamp unix timestamp computed from ExpectedDateTime
• DisplayTime string in varying format as is displayed on signs at stops

All times are given in Stockholm local time. Display time can be in format HH:MM or xx min or "Nu" (=Swedish for now).

API levels

Please be aware that the start level (Brons) of your API-Key can only make 10k API calls per month. That is not enough to update the data every minute. At that level you can only request updates every 5 minutes. Silver level gives you already plenty of calls to work with.

Future development

Please let me know if you would like to cover any other use cases.