[receiver/mongodbatlas] Adds additional disk & process metrics (open-…

…telemetry#36694)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
Adds additional disk and process metrics to flesh out available
monitoring metrics from the API. No new API calls were needed as we were
already getting this data already.

<!-- Issue number (e.g. open-telemetry#1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes open-telemetry#36525

<!--Describe what testing was performed and which tests were added.-->
#### Testing
New tests generated and ran.

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#### Documentation
New documentation generated.

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---------

Co-authored-by: schmikei <keith.schmitty@gmail.com>

.chloggen/mongodbatlasreceiver-metric-adds.yaml

@@ -0,0 +1,31 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: mongodbatlasreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Adds additional metrics to the MongoDB Atlas receiver"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [36525]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  Adds a number of new default disabled metrics to the MongoDB Atlas receiver. These metrics are:
+  - mongodbatlas.disk.partition.queue.depth
+  - mongodbatlas.disk.partition.throughput
+  - mongodbatlas.process.cache.ratio
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

receiver/mongodbatlasreceiver/documentation.md

@@ -424,7 +424,7 @@ Aggregate of MongoDB Metrics DOCUMENT_METRICS_UPDATED, DOCUMENT_METRICS_DELETED,
 
 DB Operation Rates
 
-Aggregate of MongoDB Metrics OPCOUNTER_GETMORE, OPERATIONS_SCAN_AND_ORDER, OPCOUNTER_UPDATE, OPCOUNTER_REPL_UPDATE, OPCOUNTER_CMD, OPCOUNTER_DELETE, OPCOUNTER_REPL_DELETE, OPCOUNTER_REPL_CMD, OPCOUNTER_QUERY, OPCOUNTER_REPL_INSERT, OPCOUNTER_INSERT
+Aggregate of MongoDB Metrics OPCOUNTER_GETMORE, OPERATIONS_SCAN_AND_ORDER, OPCOUNTER_UPDATE, OPCOUNTER_REPL_UPDATE, OPCOUNTER_CMD, OPCOUNTER_DELETE, OPCOUNTER_REPL_DELETE, OPCOUNTER_REPL_CMD, OPCOUNTER_QUERY, OPCOUNTER_REPL_INSERT, OPCOUNTER_INSERT, OPCOUNTER_TTL_DELETED
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
@@ -434,7 +434,7 @@ Aggregate of MongoDB Metrics OPCOUNTER_GETMORE, OPERATIONS_SCAN_AND_ORDER, OPCOU
 
 | Name | Description | Values |
 | ---- | ----------- | ------ |
-| operation | Type of database operation | Str: ``cmd``, ``query``, ``update``, ``delete``, ``getmore``, ``insert``, ``scan_and_order`` |
+| operation | Type of database operation | Str: ``cmd``, ``query``, ``update``, ``delete``, ``getmore``, ``insert``, ``scan_and_order``, ``ttl_deleted`` |
 | cluster_role | Whether process is acting as replica or primary | Str: ``primary``, ``replica`` |
 
 ### mongodbatlas.process.db.operations.time
@@ -933,6 +933,58 @@ Aggregate of MongoDB Metrics MAX_SWAP_USAGE_FREE, MAX_SWAP_USAGE_USED
 | ---- | ----------- | ------ |
 | memory_state | Memory usage type | Str: ``resident``, ``virtual``, ``mapped``, ``computed``, ``shared``, ``free``, ``used`` |
 
+## Optional Metrics
+
+The following metrics are not emitted by default. Each of them can be enabled by applying the following configuration:
+
+```yaml
+metrics:
+  <metric_name>:
+    enabled: true
+```
+
+### mongodbatlas.disk.partition.queue.depth
+
+Disk queue depth
+
+Aggregate of MongoDB Metrics DISK_QUEUE_DEPTH
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| 1 | Gauge | Double |
+
+### mongodbatlas.disk.partition.throughput
+
+Disk throughput
+
+Aggregate of MongoDB Metrics DISK_PARTITION_THROUGHPUT_READ, DISK_PARTITION_THROUGHPUT_WRITE
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| By/s | Gauge | Double |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| disk_direction | Measurement type for disk operation | Str: ``read``, ``write``, ``total`` |
+
+### mongodbatlas.process.cache.ratio
+
+Cache ratios represented as (%)
+
+Aggregate of MongoDB Metrics CACHE_FILL_RATIO, DIRTY_FILL_RATIO
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| % | Gauge | Double |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| cache_ratio_type | Cache ratio type | Str: ``cache_fill``, ``dirty_fill`` |
+
 ## Resource Attributes
 
 | Name | Description | Values | Enabled |