`InfoProvider` is now `InfoContributor` and contributes to the `Info`
instance via a builder. The `Info` instance is immutable. Each
contributor can be disabled via the `management.info.<name>.enabled`
key or all can be disabled using `management.info.defaults.enabled` (this
is similar to what the health endpoint does).
By default, all keys from the environment starting with `info.` are
exposed. If a `git.properties` file is present in the classpath, the
content of `GitInfo` is exposed using the `git` key.
A `SimpleInfoContributor` and `AbstractEnvironmentInfoContributor` are
available for convenience. `InfoContributor` instances can be ordered
the usual way, with a default order provided by
`InfoProviderAutoConfiguration#DEFAULT_ORDER`.
Closes gh-3492
Then we can optionally find a non-anonymous principal if there
is one. If the user is anonymous then the health result is cached
up to endpoints.health.ttl (default 1000ms) to prevent a DOS attack.
Fixes gh-1353
Since Spring supports gobal error handling through
@ControllerAdvice, it is quite easy to set up more meta-data
about an exception for the BasicErrorController. You need
to be careful not to swallow Security exceptions, and probably
others (optionally) so this feature needs a bit more work.
See gh-538
Long package names are really unnecessary in samples and they
just clutter things up. Also Spring Loaded doesn't work with
org.sfw packages, so to demo that technology you need a
different package name.
Main user-facing interface is still Counter/GaugeService but the
back end behind that has more options. The Default*Services write
metrics to a MetricWriter and there are some variants of that, and
also variants of MetricReader (basic read-only actions).
MetricRepository is now a combination of MetricReader, MetricWriter
and some more methods that make it a bit more repository like.
There is also a MultiMetricReader and a MultiMetricRepository for
the common case where metrics are stored in related (often open
ended) groups. Examples would be complex metrics like histograms
and "rich" metrics with averages and statistics attached (which
are both closed) and "field counters" which count the occurrences
of values of a particular named field or slot in an incoming message
(e.g. counting Twitter hastags, open ended).
In memory and redis implementations are provided for the repositories.
Generally speaking the in memory repository should be used as a
local buffer and then scheduled "exports" can be executed to copy
metric values accross to a remote repository for aggregation.
There is an Exporter interface to support this and a few implementations
dealing with different strategies for storing the results (singly or
grouped).
Codahale metrics are also supported through the MetricWriter interface.
Currently implemented through a naming convention (since Codahale has
a fixed object model this makes sense): metrics beginning with "histogram"
are Histograms, "timer" for Timers, "meter" for Meters etc.
Support for message driven metric consumption and production are provided
through a MetricWriterMessageHandler and a MessageChannelMetricWriter.
No support yet for pagination in the repositories, or for HATEOAS style
HTTP endpoints.
