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Overview

Metadata providers are a key component; Shibboleth is a 100% metadata-driven SAML implementation and has no other means of provisioning relationships with IdPs. If you don't have metadata for an IdP you have to create it.

Like most plugins, the type attribute determines which type of plugin to use. Each type may support its own attributes and child elements, in addition to the Common Attributes and Common Elements listed below.

Note that when multiple providers are configured, the behavior is unspecified when an entityID is present in more than one provider/source. The specifics of what happens at present depend on whether there are differences between the metadata that could be relevant to what the SP is actually searching for, but in most cases the first one found will trump later instances. That is not guaranteed behavior, merely the current behavior.

Types

typeFunction

XML

Loads metadata from a file or HTTP resource, including batches or "aggregates" of metadata for multiple IdPs

Dynamic

Loads metadata "on demand" (dynamically) from a remote HTTP server, one IdP at a time

MDQ

A special type of dynamic metadata source that adheres to an IETF draft standard convention for constructing a query URL

LocalDynamic

A special type of dynamic metadata source that loads metadata on-demand from a local directory of files

Folder

Largely replaced by the LocalDynamic type, this batch-loads metadata from all the files contained in a specified directory

Reference

Attributes

Common Attributes

The following attributes are supported for all MetadataProvider types:
NameTypeReq?DefaultDescription
type
stringY

Specifies the exact type of metadata plugin to use

id
string

A label for the metadata source, used in logging and status reporting
validate
boolean
falseWhether the XML should be schema validated before it is parsed. Note that some sources of metadata (e.g., ADFS) may contain a large number of extensions. The SP now includes a number of additional schemas to make validation of such extensions possible, but there are always exceptions.

Dynamic Provider Attributes

The following attributes are supported only for the "dynamic" (on-demand) MetadataProvider types (MDQDynamicLocalDynamic):
NameTypeDefaultDescription
cleanupIntervaltime in seconds1800 (30 mins)

Time in seconds between execution of background thread to scan for expired cached metadata and remove it from memory. You can set this to 0 to disable any cleanup, but this will potentially cause memory usage to grow.

cleanupTimeouttime in seconds

1800 (30 mins)

Extra time to leave recently-unused entries in the cache before the background cleanup process will remove them
maxCacheDuration time in seconds28800 (8 hours)Upper bound on time before attempt to reload metadata for an entity
minCacheDurationtime in seconds600 (10 mins)Lower bound on time before attempt to reload metadata for an entity
refreshDelayFactordecimal0.75Factor applied to the metadata's own validity or caching period to determine the reload interval to use. Once applied, the result is bounded by the minCacheDuration and maxCacheDuration settings to determine the time of the next attempt. If reload attempts fail, the existing metadata (if any) will be reused until it actually expires
negativeCachebooleansee description

Controls whether lookup failures are cached (for the minCacheDuration). This can avoid repeatedly accessing a server which is failing or simply has no metadata.

Defaults to "true" for remote dynamic metadata providers (MDQ, Dynamic) and "false" for the LocalDynamicProvider


Remote Dynamic Provider Attributes

The following attributes are supported only for the remote dynamic MetadataProvider types (MDQDynamic):
NameTypeDefaultDescription
cacheDirectory
string
Defines a directory in which downloaded metadata will be cached. During startup the directory is also scanned and the metadata loaded to prime the in-memory cache. This directory should be unique for every metadata provider configured.
backgroundInitializebooleantrueFlag indicating whether the plugin should initialize itself from the cache in the background to improve startup time. It has no effect if cacheDirectory is unset.
verifyHostbooleantrueIf true, attempts to resolve metadata using a TLS-enabled URL will verify the hostname in the server's certificate against the expected hostname (but this is the extent of the validation performed unless other configuration is in place)
ignoreTransportbooleanfalseIf true, authentication of the transport layer will be ignored when resolving metadata. If false, a <TrustEngine> child element must be specified.

Child Elements

Common Child Elements

The following child elements are supported across all MetadataProvider types:

Name

Cardinality

Description

<MetadataFilter>anyMetadata filter plugins to run
<KeyInfoResolver>0 or 1Not generally used, it provides an extension point to override the low-level handling of <ds:KeyInfo> elements and would be necessary to add support for some kind of custom XML key representation

Remote Dynamic Provider Child Elements

The following child elements are supported by the remote, on-demand MetadataProvider types (MDQDynamic):

Name

Cardinality

Description

<TrustEngine>0 or 1

A TrustEngine plugin to apply to a server's certificate when resolving metadata using a TLS-enabled URL.

This trust engine obviously cannot require the use of metadata to operate. If not supplied, the ignoreTransport attribute must be set to true to avoid a configuration error. This is done to prevent a misconfigured trust engine from resulting in insecure metadata resolution.


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