Docs: Update s3 repository docs with client settings (#26033)

This commit updates the s3 repository docs to clearly mark settings as
part of the s3 client settings, as well as those that are secure and
must be stored in the elasticsearch keystore.

relates #25619

docs/plugins/repository-s3.asciidoc

@@ -12,90 +12,112 @@ include::install_remove.asciidoc[]
 [[repository-s3-usage]]
 ==== Getting started with AWS
 
-The plugin will default to using
+The plugin provides a repository type named `s3` which may be used when creating a repository.
+The repository defaults to using
 http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html[IAM Role]
-credentials for authentication. These can be overridden by, in increasing
-order of precedence, system properties `aws.accessKeyId` and `aws.secretKey`,
-environment variables `AWS_ACCESS_KEY_ID` and `AWS_SECRET_KEY`, or the
-elasticsearch config using `cloud.aws.access_key` and `cloud.aws.secret_key` or
-if you wish to set credentials specifically for s3 `cloud.aws.s3.access_key` and `cloud.aws.s3.secret_key`:
+credentials for authentication. The only mandatory setting is the bucket name:
 
-[source,yaml]
+[source,js]
 ----
-cloud:
-    aws:
-        access_key: AKVAIQBF2RECL7FJWGJQ
-        secret_key: vExyMThREXeRMm/b/LRzEB8jWwvzQeXgjqMX+6br
+PUT _snapshot/my_s3_repository
+{
+  "type": "s3",
+  "settings": {
+    "bucket": "my_bucket"
+  }
+}
 ----
+// CONSOLE
+// TEST[skip:we don't have s3 setup while testing this]
+
 
-[[repository-s3-usage-security]]
-===== Transport security
+[[repository-s3-client]]
+==== Client Settings
 
-By default this plugin uses HTTPS for all API calls to AWS endpoints. If you wish to configure HTTP you can set
-`cloud.aws.protocol` in the elasticsearch config. You can optionally override this setting per individual service
-via: `cloud.aws.ec2.protocol` or `cloud.aws.s3.protocol`.
+The client used to connect to S3 has a number of settings available. Client setting names are of
+the form `s3.client.CLIENT_NAME.SETTING_NAME` and specified inside `elasticsearch.yml`.  The
+default client name looked up by an s3 repository is called `default`, but can be customized
+with the repository setting `client`. For example:
 
-[source,yaml]
+[source,js]
 ----
-cloud:
-    aws:
-        protocol: https
-        s3:
-            protocol: http
-        ec2:
-            protocol: https
+PUT _snapshot/my_s3_repository
+{
+  "type": "s3",
+  "settings": {
+    "bucket": "my_bucket",
+    "client": "my_alternate_client"
+  }
+}
 ----
+// CONSOLE
+// TEST[skip:we don't have s3 setup while testing this]
 
-In addition, a proxy can be configured with the `proxy.host`, `proxy.port`, `proxy.username` and `proxy.password` settings
-(note that protocol can be `http` or `https`):
+Some settings are sensitive and must be stored in the {ref}/secure-settings.html[elasticsearch keystore].
+For example, to use explicit AWS access keys:
 
-[source,yaml]
+[source,sh]
 ----
-cloud:
-    aws:
-        protocol: https
-        proxy:
-            host: proxy1.company.com
-            port: 8083
-            username: myself
-            password: theBestPasswordEver!
+bin/elasticsearch-keystore add s3.client.default.access_key
+bin/elasticsearch-keystore add s3.client.default.secret_key
 ----
 
-You can also set different proxies for `ec2` and `s3`:
+The following are the available client settings. Those that must be stored in the keystore
+are marked as `Secure`.
 
-[source,yaml]
-----
-cloud:
-    aws:
-        s3:
-            proxy:
-                host: proxy1.company.com
-                port: 8083
-                username: myself1
-                password: theBestPasswordEver1!
-        ec2:
-            proxy:
-                host: proxy2.company.com
-                port: 8083
-                username: myself2
-                password: theBestPasswordEver2!
-----
+`access_key`::
 
-===== Read timeout
+    An s3 access key. The `secret_key` setting must also be specified. (Secure)
 
-Read timeout determines the amount of time to wait for data to be transferred over an established,
-open connection before the connection is timed out. Defaults to AWS SDK default value (`50s`).
-It can be configured with `cloud.aws.read_timeout` (or `cloud.aws.s3.read_timeout`) setting:
+`secret_key`::
 
-[source, yaml]
-----
-cloud.aws.read_timeout: 30s
-----
+    An s3 secret key. The `access_key` setting must also be specified. (Secure)
+
+`endpoint`::
+
+    The s3 service endpoint to connect to. This will be automatically
+    figured out by the s3 client based on the bucket location, but
+    can be specified explicitly. See http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region.
+
+`protocol`::
+
+    The protocol to use to connect to s3. Valid values are either `http`
+    or `https`. Defaults to `https`. 
+
+`proxy.host`::
+
+    The host name of a proxy to connect to s3 through.
+
+`proxy.port`::
+
+    The port of a proxy to connect to s3 through.
+
+`proxy.username`::
+
+    The username to connect to the `proxy.host` with. (Secure)    
+
+`proxy.password`::
+
+    The password to connect to the `proxy.host` with. (Secure)    
+
+`read_timeout`::
+
+    The socket timeout for connecting to s3. The value should specify the unit. For example,
+    a value of `5s` specifies a 5 second timeout. The default value is 50 seconds.
+
+`max_retries`::
+
+    The number of retries to use when an s3 request fails. The default value is 3.
+
+`use_throttle_retries`::
+
+    Whether retries should be throttled (ie use backoff). Must be `true` or `false`. Defaults to `false`.
 
 [[repository-s3-repository]]
-==== S3 Repository
+==== Repository Settings
 
-The S3 repository is using S3 to store snapshots. The S3 repository can be created using the following command:
+The `s3` repository type supports a number of settings to customize how data is stored in S3.
+These can be specified when creating the repository. For example:
 
 [source,js]
 ----
@@ -103,7 +125,8 @@ PUT _snapshot/my_s3_repository
 {
   "type": "s3",
   "settings": {
-    "bucket": "my_bucket_name"
+    "bucket": "my_bucket_name",
+    "another_setting": "setting_value"
   }
 }
 ----
@@ -116,15 +139,9 @@ The following settings are supported:
 
     The name of the bucket to be used for snapshots. (Mandatory)
 
-`endpoint`::
-
-    The endpoint for the S3 region in which the bucket exists. The default S3 endpoint
-    will automatically find the region of the configured bucket and forward to there.
+`client`::
 
-`protocol`::
-
-    The protocol to use (`http` or `https`). Defaults to value of
-    `cloud.aws.protocol` or `cloud.aws.s3.protocol`.
+    The name of the s3 client to use to connect to S3. Defaults to `default`.
 
 `base_path`::
 
@@ -134,16 +151,6 @@ The following settings are supported:
     However, this has been deprecated and setting the base_path now should
     omit the leading `/`.
 
-`access_key`::
-
-    The access key to use for authentication. Defaults to value of
-    `cloud.aws.access_key`.
-
-`secret_key`::
-
-    The secret key to use for authentication. Defaults to value of
-    `cloud.aws.secret_key`.
-
 `chunk_size`::
 
     Big files can be broken down into chunks during snapshotting if needed.
@@ -172,18 +179,6 @@ The following settings are supported:
     Multipart API and may result in upload errors. Defaults to the minimum
     between `100mb` and `5%` of the heap size.
 
-`max_retries`::
-
-    Number of retries in case of S3 errors. Defaults to `3`.
-
-`use_throttle_retries`::
-
-    Set to `true` if you want to throttle retries. Defaults to AWS SDK default value (`false`).
-
-`readonly`::
-
-    Makes repository read-only. Defaults to `false`.
-
 `canned_acl`::
 
     The S3 repository supports all http://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl[S3 canned ACLs]
@@ -200,22 +195,6 @@ The following settings are supported:
     currently supported by the plugin. For more information about the
     different classes, see http://docs.aws.amazon.com/AmazonS3/latest/dev/storage-class-intro.html[AWS Storage Classes Guide]
 
-`path_style_access`::
-
-    Activate path style access for http://docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosting.html[virtual hosting of buckets].
-    The default behaviour is to detect which access style to use based on the configured endpoint (an IP will result
-    in path-style access) and the bucket being accessed (some buckets are not valid DNS names).
-
-Note that you can define S3 repository settings for all S3 repositories in `elasticsearch.yml` configuration file.
-They are all prefixed with `repositories.s3.`. For example, you can define compression for all S3 repositories
-by setting `repositories.s3.compress: true` in `elasticsearch.yml`.
-
-The S3 repositories use the same credentials as the rest of the AWS services
-provided by this plugin (`discovery`). See <<repository-s3-usage>> for details.
-
-Multiple S3 repositories can be created. If the buckets require different
-credentials, then define them as part of the repository settings.
-
 [[repository-s3-permissions]]
 ===== Recommended S3 Permissions
 
@@ -321,15 +300,6 @@ specific bucket like this:
 ----
 // NOTCONSOLE
 
-[[repository-s3-endpoint]]
-===== Using other S3 endpoint
-
-If you are using any S3 api compatible service, you can set a global endpoint by setting `cloud.aws.s3.endpoint`
-to your URL provider. Note that this setting will be used for all S3 repositories.
-
-Different `endpoint` and `protocol` settings can be set on a per-repository basis
-See <<repository-s3-repository>> for details.
-
 [[repository-s3-aws-vpc]]
 [float]
 ==== AWS VPC Bandwidth Settings