nems-api

nems-api is a web-based api interface that outputs json data related to your NEMS server. It is lightweight, fast, and offers a connection for both internal NEMS features and third-party devices.

nems-api will always return either success: true or success: false to tell you whether a query was successful or not.

IP Restrictions

By default, access to nems-api is limited to the following IP addresses:

127.0.0.1
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

If you need to add an outside IP address, please put in a feature request in the Community Forum to add this feature to NEMS-SST. If there is demand for it, it will be added.

Secure Certificate

NEMS Linux uses self-signed certificates. In order to pull nems-api data over ssl (ie., https), you must ignore the certificates via your application.

Command Examples

All examples in this document assume that the API is available at

http://nems.local/nems-api/

http://nems.local/nems-api/hosts - output all configured hosts
http://nems.local/nems-api/services - output all configured services
http://nems.local/nems-api/downtimes - output all scheduled downtimes
http://nems.local/nems-api/hosts?Columns=name,state - output all host names along with their current state

Response Format

All responses are in JSON and have the following format:

{"success": <bool>, "content": <object>}

If “success” is true, “content” will contain the requested data. If false, it will contain

{"code": <int>, "message": <string>}

where “code” is the mk-livestatus error code and “message” is a human-readable explanation of the error.

Query interface

The query interface returns a list of objects in JSON. The available endpoints are the same as the tables available from mk-livestatus itself:

hosts
services - Nagios services, joined with all data from hosts
hostgroups
servicegroups
contactgroups
servicesbygroup - all services grouped by service groups
servicesbyhostgroup - all services grouped by host groups
hostsbygroup - all hosts grouped by host groups
contacts
commands - your defined Nagios commands
timeperiods - time period definitions (currently only name and alias)
downtimes - all scheduled host and service downtimes, joined with data from hosts and services.
comments - all host and service comments
log - a transparent access to the nagios logfiles
status - general performance and status information. This table contains exactly one dataset.
columns - a complete list of all tables and columns available via Livestatus, including descriptions!
statehist - sla statistics for hosts and services, joined with data from hosts, services and log.

To retrieve all records from a table, send a GET request to

http://nems.local/nems-api/{tablename}

For example, to get all host records from the server, GET

http://nems.local/nems-api/hosts

Columns

To limit the returned data to a subset of the available fields, pass a Columns query parameter containing a comma-separated list of column names. To fetch the name and services list for all hosts:

http://nems.local/nems-api/hosts?Columns=name,services

Filters

To filter the result set to records meeting some criteria, pass one or more Filter[] params. Each Filter is a urlencoded LQL filter (see the [mk-livestatus documentation](http://mathias-kettner.com/checkmk_livestatus.html#H1:LQL - The Livestatus Query Language) for detailed LQL filter syntax). If more than one filter is specified, they are ANDed together. To get all hosts starting with “api” in state OK (0):

http://nems.local/nems-api/hosts?Filter[]=name - ^api&Filter[]=state = 0

Stats

Stats queries allow you to get a count of objects matching a criteria. Stats queries return a list of counts and never take a Columns parameter. You can request several Stats with a single API call. You can also restrict the objects counted by adding Filters to your query. To count the number of hosts starting with “api” in state OK:

http://nems.local/nems-api/hosts?&Stats[]=name - ^api&Filter[]=state = 0

Command Interface

All calls to nems-api to execute Nagios commands must be HTTP POST requests.

Acknowledgements

Acknowledgements for host and service alerts can be sent via the acknowledge_problem endpoint.

Acknowledge Host Alerts

curl -is -XPOST https://nems.local/nems-api/acknowledge_problem -d '{"host": "host.example.com", "author": "rfrantz", "comment": "acked from livestatus"}'

Acknowledge Service Alerts

Acknowledging service alerts is similar to host alerts, with the addition of the service parameter:

curl -is -XPOST https://nems.local/nems-api/acknowledge_problem -d '{"host": "host.example.com", "service": "Apache", "author": "rfrantz", "comment": "acked from livestatus"}'

Downtime

cancel_downtime

Existing scheduled downtimes for a host can be canceled. cancel_downtime expects the downtime_id parameter. Downtime IDs can be found by querying a host and extracting the downtimes array:

curl -s https://nems.local/nems-api/hosts?Filter=name = my_host | jq '.' | grep 'downtimes"' -A 2

"downtimes": [
    12345
],

The subsequent request to cancel the host’s downtime is:

curl -s -XPOST 'https://nems.local/nems-api/cancel_downtime' -d '{"downtime_id": "12345"}'

To cancel the downtime for a service, pass the name of the service along with the downtime_id:

curl -s -XPOST 'https://nems.local/nems-api/cancel_downtime' -d '{"downtime_id": "12345", "service": "CPU"}'

schedule_downtime

Schedule downtime for a host as follows:

curl -s -XPOST 'https://nems.local/nems-api/schedule_downtime' -d '{"host": "host.example.com", "duration": "7200", "author": "rfrantz", "comment": "Downtimed via livestatus"}'

NOTE: The duration field expects a value whose unit is in seconds.

Downtimes can be scheduled for a particular service by adding a "service" parameter:

curl -s -XPOST 'https://nems.local/nems-api/schedule_downtime' -d '{"host": "host.example.com", "service": "CPU", duration": "7200", "author": "rfrantz", "comment": "Downtimed via livestatus"}'

Notifications

disable_notifications

Notifications for a host, a host’s service, or all of the host’s services can be disabled via the disable_notifications endpoint.

Disable Host Notifications

Send a request that includes a valid ‘host’ value:

curl -s -XPOST 'https://nems.local/nems-api/disable_notifications' -d '{"host": "host.example.com"}'

Disable Notifications for a Host’s Service

Send a request that includes valid ‘host’ and ‘service’ values:

curl -s -XPOST 'https://nems.local/nems-api/disable_notifications' -d '{"host": "host.example.com", "service": "httpd"}'

Disable Notifications for All of a Host’s Services

Send a request that includes a valid ‘host’ value and set ‘scope’ to ‘all’:

curl -s -XPOST 'https://nems.local/nems-api/disable_notifications' -d '{"host": "host.example.com", "scope": "all"}'

enable_notifications

Notifications for a host, a host’s service, or all of the host’s services can be enabled via the enable_notifications endpoint.

Enable Host Notifications

Send a request that includes a valid ‘host’ value:

curl -s -XPOST 'https://nems.local/nems-api/enable_notifications' -d '{"host": "host.example.com"}'

Enable Notifications for a Host’s Service

Send a request that includes valid ‘host’ and ‘service’ values:

curl -s -XPOST 'https://nems.local/nems-api/enable_notifications' -d '{"host": "host.example.com", "service": "httpd"}'

Enable Notifications for All of a Host’s Services

Send a request that includes a valid ‘host’ value and set ‘scope’ to ‘all’:

curl -s -XPOST 'https://nems.local/nems-api/enable_notifications' -d '{"host": "host.example.com", "scope": "all"}'