curl_xml plugin¶

See this section in the full configuration reference

The curl_xml plugin uses libcurl (http://curl.haxx.se/) and libxml2 (http://xmlsoft.org/) to retrieve XML data via cURL.

<Plugin "curl_xml">
  <URL "http://localhost/stats.xml">
    AddressFamily "any"
    Host "my_host"
    #Plugin "curl_xml"
    Instance "some_instance"
    User "collectd"
    Password "thaiNg0I"
    VerifyPeer true
    VerifyHost true
    CACert "/path/to/ca.crt"
    Header "X-Custom-Header: foobar"
    Post "foo=bar"

    <XPath "table[@id=\"magic_level\"]/tr">
      Type "magic_level"
      #InstancePrefix "prefix-"
      InstanceFrom "td[1]"
      #PluginInstanceFrom "td[1]"
      ValuesFrom "td[2]/span[@class=\"level\"]"
    </XPath>
  </URL>
</Plugin>

In the Plugin block, there may be one or more URL blocks, each defining a URL to be fetched using libcurl. Within each URL block there are options which specify the connection parameters, for example authentication information, and one or more XPath blocks.

Each XPath block specifies how to get one type of information. The string argument must be a valid XPath expression which returns a list of "base elements". One value is dispatched for each "base element". The type instance and values are looked up using further XPath expressions that should be relative to the base element.

Within the URL block the following options are accepted:

AddressFamily Type

IP version to resolve URL to. Useful in cases when hostname in URL resolves to both IPv4 and IPv6 addresses, and you are interested in using one of them specifically. Use ipv4 to enforce IPv4, ipv6 to enforce IPv6, or any to keep the default behavior of resolving addresses to all IP versions your system allows. If libcurl is compiled without IPv6 support, using ipv6 will result in a warning and fallback to any. If Type cannot be parsed, a warning will be printed and the whole URL block will be ignored.

Host Name

Use Name as the host name when submitting values. Defaults to the global host name setting.

Plugin Plugin

Use Plugin as the plugin name when submitting values. Defaults to 'curl_xml'.

Instance Instance

Use Instance as the plugin instance when submitting values. May be overridden by PluginInstanceFrom option inside XPath blocks. Defaults to an empty string (no plugin instance).

Interval Interval

Sets the interval (in seconds) in which the values will be collected from this URL. By default the global Interval setting will be used.

Namespace Prefix URL

If an XPath expression references namespaces, they must be specified with this option. Prefix is the "namespace prefix" used in the XML document. URL is the "namespace name", an URI reference uniquely identifying the namespace. The option can be repeated to register multiple namespaces.

Examples:

Namespace "s" "http://schemas.xmlsoap.org/soap/envelope/"
Namespace "m" "http://www.w3.org/1998/Math/MathML"

User User

Password Password

Digest true|false

VerifyPeer true|false

VerifyHost true|false

CACert CA Cert File

Header Header

Post Body

Timeout Milliseconds

These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see there for a detailed description.

<StatisticsE<gt>

One Statistics block can be used to specify cURL statistics to be collected for each request to the remote URL. See the section "cURL Statistics" above for details.

<XPath XPath-expression>

Within each URL block, there must be one or more XPath blocks. Each XPath block specifies how to get one type of information. The string argument must be a valid XPath expression which returns a list of "base elements". One value is dispatched for each "base element".

Within the XPath block the following options are accepted:

Type Type

Specifies the Type used for submitting patches. This determines the number of values that are required / expected and whether the strings are parsed as signed or unsigned integer or as double values. See types.db(5) for details. This option is required.

InstancePrefix InstancePrefix

Prefix the type instance with InstancePrefix. The values are simply concatenated together without any separator. This option is optional.

InstanceFrom InstanceFrom

Specifies a XPath expression to use for determining the type instance. The XPath expression must return exactly one element. The element's value is then used as type instance, possibly prefixed with InstancePrefix (see above).

PluginInstanceFrom PluginInstanceFrom

Specifies a XPath expression to use for determining the plugin instance. The XPath expression must return exactly one element. The element's value is then used as plugin instance.

If the "base XPath expression" (the argument to the XPath block) returns exactly one argument, then InstanceFrom and PluginInstanceFrom may be omitted. Otherwise, at least one of InstanceFrom or PluginInstanceFrom is required.

ValuesFrom ValuesFrom [ValuesFrom ...]

Specifies one or more XPath expression to use for reading the values. The number of XPath expressions must match the number of data sources in the type specified with Type (see above). Each XPath expression must return exactly one element. The element's value is then parsed as a number and used as value for the appropriate value in the value list dispatched to the daemon. This option is required.