Keywords: Supervision, Icinga, Nagios, Linux

11.4. The Icinga-Web REST API
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## 11.4. The Icinga-Web REST API

In this document we'll describe the Icinga-Web REST API (yes, we know that the term is not yet completed) which allows you to request your monitoring information via GET or POST requests (in the future (>1.2), you will also be able to send commands via PUT).

### 11.4.1. Why should I use the API?

For most people, the combination Icinga/Icinga-Web will fit most needs. You can watch your monitoring status, act on problems and extend it to suit your needs (Modules/Cronks).

But sometimes, you have another piece of software that is interested in some monitoring data (for example: Icinga-Chromed-Status). You could parse the cgi output of Icinga (many programs do that at this time), but that's not really a high performance solution - and certainly no fun for the developer. The goal of the REST API is to return the data you want (and only the data you want) in a standardized, machine-readable format like JSON or XML

### 11.4.2. Features of the Icinga-Web REST API

Currently supported (v1.2):

- Availability of almost all monitoring fields via GET or POST.

- Return data as xml or json.

- AND & OR search filtergroups with unlimited nesting levels (AND)).

- You choose which columns you want returned, not the API (less overhead).

- Support of limit, offset, order, group by.

- Return an additional total count field.

- Authorization via auth_key in request or cookies.

- Respects Icinga-web principals (for example, limit to specific hostgroups).

Planned in future(> 1.2):

- Send commands via PUT

### 11.4.3. What's the difference between the Icinga-API and the Icinga-Web REST API?

The Icinga-API can at this point considered as an internal toolkit to access the database informations. In fact, the REST API acts on top of this API and extends it via the HTTP protocol. In the future, the Icinga-API will be merged into Icinga-Web.

### 11.4.4. Prerequisites

In order to use the API, you first have to enable the Auth provider for it. This can be done under icinga-web/app/modules/AppKit/config/auth.xml.

Change "auth_enabled" to 'true' in this section:

    <ae:parameter name="auth_key">
        <ae:parameter name="auth_module">AppKit</ae:parameter>
        <ae:parameter name="auth_provider">Auth.Provider.AuthKey</ae:parameter>
        <ae:parameter name="auth_enable">true</ae:parameter>
        <ae:parameter name="auth_authoritative">true</ae:parameter>
    </ae:parameter>

| Note
If you edit any *.xml file you have to clear the cache afterwards!

    rm -f app/cache/config/*.php

or

    icinga-web/bin/clearcache.sh

Now, in Icinga-Web, you have to add a user with API access:

- Create a new user

- Choose auth_key in the Auth_via field

- Insert an API key to use

- Under principals, add the appkit.api.access principal

That's it, now you can start.

### 11.4.5. Reference

So, here are the goodies. In the next few points we'll explain how the API can be accessed:

### 11.4.6. GET

Advantages:

- Easy to use, it's just an URL!

- You always see what parameters have been requested.

Disadvantages:

- If you request it in a browser your API key could be in the browser history.

- In a browser, you cannot add URLs with unlimited size (2,083 characters for Internet explorer, for example).

- Especially when parameters are escaped, the parameter list lacks a bit of clarity.

### 11.4.7. The structure of the URL:

To access the api, the URL should look as in the following (italics are optional, bold ones are required) host.com/icinga-web/web/api/ TARGET / COLUMNS / FILTER / ORDER / GROUPING / LIMIT / COUNTFIELD / OUTPUT_TYPE

### 11.4.8. The Parameters en detail:

- TARGET: Which field to request, is a simple string like host.

- COLUMNS: A listing of columns to return, must look like this: columns[COL1|COL2|COL3|...]

- FILTER: Defines which filters to use in the request. Must always be nested in AND or OR groups.

  The filter itself looks like this:

      filters[AND/OR(COLUMN|OPERATOR|VALUE;COLUMN2|OPERATOR2|VALUE2;OR(...),AND]

  Example: Select all services with smtp in the name, but only if they're ok or unknown

  Wrong:

      filters[SERVICE_NAME|like|*smtp*;OR(SERVICE_CURRENT_STATE|=|0;SERVICE_CURRENT_STATE|=|3)]

  You always need a nesting level at the beginning, see:

  Correct:

      filters[AND ( SERVICE_NAME|like|*smtp*;OR ( SERVICE_CURRENT_STATE|=|0;SERVICE_CURRENT_STATE|=|3 ) )]

- ORDER: Defines which field to use for ordering and if ascending or descending ordering should be used. Example: order[COLUMN| ASC or DESC]

- GROUPING: Defines a field to group by: group[COL]

- LIMIT: Defines a starting offset and/or a limit: limit[START;END ( if needed ) ]

- COUNTFIELD: Adds a total field to the result which counts by this field (in most cases, the id): countColumn=COL

- OUTPUT: At this time either json or xml

### 11.4.9. Example for GET

Get all services that are critical or warning, but have a host that is ok. Sort descending by the service state and count the services. Authentification is done via authkey (here APITEST123456). The request is broken into pieces for better readability, XML:

    http://localhost/icinga-web/web/api/service/filter[AND(HOST_CURRENT_STATE|=|0;OR(SERVICE_CURRENT_STATE|=|1;SERVICE_CURRENT_STATE|=|2))]/
    columns(SERVICE_NAME|HOST_NAME|SERVICE_CURRENT_STATE|HOST_NAME|HOST_CURRENT_STATE|HOSTGROUP_NAME)/
    order(SERVICE_CURRENT_STATE;DESC)/countColumn=SERVICE_ID/authkey=APITEST123456/xml

This would return something like:

    <results>
       <result>
           <column name="SERVICE_ID">295</column>
           <column name="SERVICE_OBJECT_ID">139</column>
           <column name="SERVICE_IS_ACTIVE">1</column>
           <column name="SERVICE_INSTANCE_ID">1</column>
           <column name="SERVICE_NAME">MailQ</column>
           <column name="SERVICE_DISPLAY_NAME">MailQ</column>
           <column name="SERVICE_OUTPUT">Error occured:error=1:0:0</column>
           <column name="SERVICE_PERFDATA"></column>
       </result>
       <result>
           <column name="SERVICE_ID">311</column>
           <column name="SERVICE_OBJECT_ID">155</column>
           <column name="SERVICE_IS_ACTIVE">1</column>
           <column name="SERVICE_INSTANCE_ID">1</column>
           <column name="SERVICE_NAME">POP3</column>
           <column name="SERVICE_DISPLAY_NAME">POP3</column>
           <column name="SERVICE_OUTPUT">Verbindungsaufbau abgelehnt</column>
           <column name="SERVICE_PERFDATA"></column>
       </result>
       <total>2</total>
    </results>

If you change the xml to json you get the same information (plus additional infos for ExtJS, which you can ignore if you're not using it) in json format:

    {"metaData":
       {"paramNames":{"start":"limit_start","limit":"limit"},
        "totalProperty":"total",
        "root":"result",
        "fields":null},
        "result": [{
           "SERVICE_ID":"295",
           "SERVICE_OBJECT_ID":"139",
           "SERVICE_IS_ACTIVE":"1",
           "SERVICE_INSTANCE_ID":"1",
           "SERVICE_NAME":"MailQ",
           "SERVICE_DISPLAY_NAME":"MailQ",
           "SERVICE_OUTPUT":"Error occured:error=1:0:0",
           "SERVICE_PERFDATA":""
       },{
           "SERVICE_ID":"311",
           "SERVICE_OBJECT_ID":"155",
           "SERVICE_IS_ACTIVE":"1",
           "SERVICE_INSTANCE_ID":"1",
           "SERVICE_NAME":"POP3",
           "SERVICE_DISPLAY_NAME":"POP3",
           "SERVICE_OUTPUT":"Connection refused",
           "SERVICE_PERFDATA":""
       }],
       "success":"true",
       "total":"2"
    }
    *CAUTION*: If you're not using the countField parameter, you'll get a flat json with the result.

### 11.4.10. POST

Advantages:

- Unlimited parameter size, as it's made for big requests.

- Your parameters don't appear in the browser history, only the base url.

- It's easier to implement in applications (ok, that's my opinion :) )

Disadvantages:

- POST will be send via the header, so you can't request it easily from the browser's address field.

### 11.4.11. Parameters en detail

The link is almost the same like the GET baselink, but with the output type in it: For example, host.com/icinga-web/web/api/json. The following parameters are supported:

- 'target': The search target, like host

- 'columns[]': An array of columns

  Example:

  columns [0] = SERVICE_NAME

  columns [1] = SERVICE_ID

- 'groups[]' : Group by this field

- 'filters_json' : A json describing how to filter

  Example:

      [{
         "type": "AND",
         "field": [{
            "type": 'atom',
            "field":  ['SERVICE_NAME'],
            "method": ['like'],
            "value":  ['*pop*']
         },{
            "type": 'OR',
            "field": [{
                "type": 'atom',
                "field": ['SERVICE_CURRENT_STATE'],
                "method": ['>'],
                "value": [0]
            },{
                "type": 'atom',
                "field": ['SERVICE_IS_FLAPPING'],
                "method": ['='],
                "value": [1]
            }]
         }]
      }]

- 'order_col' : Column to order by

- 'order_dir' : Order direction (asc oder desc)

- 'limit_start' : The offset of the records to start

- 'limit' : Limits the result to x responses

- 'countColumn' : Add a total field with this column

### 11.4.12. Example for POST

Let's take the example from Example for GET and use a post request this time. We're going to use curl, so the example can be repeated from the console:

    curl
    -d target=service
    -d 'filters_json={"type":"AND","field":[{"type":"atom","field":["HOST_CURRENT_STATE"],"method":["="],"value":[0]},{"type":"OR","field":[{"type":"atom","field":["SERVICE_CURRENT_STATE"],"method":["="],"value":[1]},{"type":"atom","field":["SERVICE_CURRENT_STATE"],"method":["="],"value" : [2] }]}]}'
    -d columns[0]=SERVICE_NAME
    -d columns[1]=HOST_NAME
    -d columns[2]=SERVICE_CURRENT_STATE
    -d columns[3]=HOST_NAME
    -d columns[4]=HOST_CURRENT_STATE
    -d columns[5]=HOSTGROUP_NAME
    -d 'order=SERVICE_CURRENT_STATE;DESC'
    -d countColumn=SERVICE_ID
    -d 'authkey=API123456'
    http://localhost/icinga-web/web/api/xml

This would return the same result as the GET request shown before.

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