OpenSearch/docs/reference/migration/migrate_5_0/plugins.asciidoc

[[breaking_50_plugins]]
=== Plugin changes

The command `bin/plugin` has been renamed to `bin/elasticsearch-plugin`. The
structure of the plugin ZIP archive has changed. All the plugin files must be
contained in a top-level directory called `elasticsearch`. If you use the
gradle build, this structure is automatically generated.

==== Plugins isolation

`isolated` option has been removed. Each plugin will have its own classloader.

==== Site plugins removed

Site plugins have been removed. Site plugins should be reimplemented as Kibana
plugins.

==== Multicast plugin removed

Multicast has been removed. Use unicast discovery, or one of the cloud
discovery plugins.

==== Plugins with custom query implementations

Plugins implementing custom queries need to implement the `fromXContent(QueryParseContext)` method in their
`QueryParser` subclass rather than `parse`. This method will take care of parsing the query from `XContent` format
into an intermediate query representation that can be streamed between the nodes in binary format, effectively the
query object used in the java api. Also, the query parser needs to implement the `getBuilderPrototype` method that
returns a prototype of the `NamedWriteable` query, which allows to deserialize an incoming query by calling
`readFrom(StreamInput)` against it, which will create a new object, see usages of `Writeable`. The `QueryParser`
also needs to declare the generic type of the query that it supports and it's able to parse.
The query object can then transform itself into a lucene query through the new `toQuery(QueryShardContext)` method,
which returns a lucene query to be executed on the data node.

Similarly, plugins implementing custom score functions need to implement the `fromXContent(QueryParseContext)`
method in their `ScoreFunctionParser` subclass rather than `parse`. This method will take care of parsing
the function from `XContent` format into an intermediate function representation that can be streamed between
the nodes in binary format, effectively the function object used in the java api. Also, the query parser needs
to implement the `getBuilderPrototype` method that returns a prototype of the `NamedWriteable` function, which
allows to deserialize an incoming function by calling `readFrom(StreamInput)` against it, which will create a
new object, see usages of `Writeable`. The `ScoreFunctionParser` also needs to declare the generic type of the
function that it supports and it's able to parse. The function object can then transform itself into a lucene
function through the new `toFunction(QueryShardContext)` method, which returns a lucene function to be executed
on the data node.

==== Cloud AWS plugin changes

Cloud AWS plugin has been split in two plugins:

* {plugins}/discovery-ec2.html[Discovery EC2 plugin]
* {plugins}/repository-s3.html[Repository S3 plugin]

Proxy settings for both plugins have been renamed:

* from `cloud.aws.proxy_host` to `cloud.aws.proxy.host`
* from `cloud.aws.ec2.proxy_host` to `cloud.aws.ec2.proxy.host`
* from `cloud.aws.s3.proxy_host` to `cloud.aws.s3.proxy.host`
* from `cloud.aws.proxy_port` to `cloud.aws.proxy.port`
* from `cloud.aws.ec2.proxy_port` to `cloud.aws.ec2.proxy.port`
* from `cloud.aws.s3.proxy_port` to `cloud.aws.s3.proxy.port`

==== Cloud Azure plugin changes

Cloud Azure plugin has been split in three plugins:

* {plugins}/discovery-azure-classic.html[Discovery Azure plugin]
* {plugins}/repository-azure.html[Repository Azure plugin]
* {plugins}/store-smb.html[Store SMB plugin]

If you were using the `cloud-azure` plugin for snapshot and restore, you had in `elasticsearch.yml`:

[source,yaml]
-----
cloud:
    azure:
        storage:
            account: your_azure_storage_account
            key: your_azure_storage_key
-----

You need to give a unique id to the storage details now as you can define multiple storage accounts:

[source,yaml]
-----
cloud:
    azure:
        storage:
            my_account:
                account: your_azure_storage_account
                key: your_azure_storage_key
-----


==== Cloud GCE plugin changes

Cloud GCE plugin has been renamed to {plugins}/discovery-gce.html[Discovery GCE plugin].

==== Delete-By-Query plugin removed

The Delete-By-Query plugin has been removed in favor of a new <<docs-delete-by-query,Delete By Query API>>
implementation in core. It now supports throttling, retries and cancellation but no longer supports timeouts.
Instead use the <<docs-delete-by-query-cancel-task-api,cancel API>> to cancel deletes that run too long.

==== Mapper Attachments plugin deprecated

Mapper attachments has been deprecated. Users should use now the {plugins}/ingest-attachment.html[`ingest-attachment`]
plugin.

==== Passing of Java System Properties

Previously, Java system properties could be passed to the plugin
command by passing `-D` style arguments directly to the plugin script.
This is no longer permitted and such system properties must be passed
via ES_JAVA_OPTS.

==== Custom plugins path

The ability to specify a custom plugins path via `path.plugins` has
been removed.

==== ScriptPlugin

Plugins that register custom scripts should implement `ScriptPlugin` and remove
their `onModule(ScriptModule)` implementation.

==== AnalysisPlugin

Plugins that register custom analysis components should implement
`AnalysisPlugin` and remove their `onModule(AnalysisModule)` implementation.

==== MapperPlugin

Plugins that register custom mappers should implement
`MapperPlugin` and remove their `onModule(IndicesModule)` implementation.

==== ActionPlugin

Plugins that register custom actions should implement `ActionPlugin` and
remove their `onModule(ActionModule)` implementation.

Plugins that register custom `RestHandler`s should implement `ActionPlugin` and
remove their `onModule(NetworkModule)` implemnetation.

==== SearchPlugin

Plugins that register custom search time behavior (`Suggester`, `ScoreFunction`,
`FetchSubPhase`, `Highlighter`, etc) should implement `SearchPlugin` and remove
their `onModule(SearchModule)` implementation.

==== Mapper-Size plugin

The metadata field `_size` is not accessible in aggregations, scripts and when
sorting for indices created in 2.x even if the index has been upgraded using the <<indices-upgrade,`upgrade`>> API.
If these features are needed in your application it is required to reindex the data with Elasticsearch 5.x.
The easiest way to reindex old indices is to use the `reindex` API, or the reindex UI provided by
the <<migration-plugin,Migration Plugin>>.