[receiver/sqlserver] Add database status metric (#33064)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
This adds one more metric, `sqlserver.properties.db.status`, which shows
the total number of databases in each state.

**Link to tracking Issue:** <Issue number if applicable>
#29865

**Testing:** <Describe what testing was performed and which tests were
added.>
Testing added, existing tests are passing.

.chloggen/sqlserver_add_db_status_metrics.yaml

@@ -0,0 +1,27 @@
+# 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: sqlserverreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add metrics for database status
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [29865]
+
+# (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:
+
+# 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/sqlserverreceiver/documentation.md

@@ -226,6 +226,22 @@ metrics:
     enabled: true
 ```
 
+### sqlserver.database.count
+
+The number of databases
+
+This metric is only available when the receiver is configured to directly connect to SQL Server.
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| {databases} | Gauge | Int |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| database.status | The current status of a database | Str: ``online``, ``restoring``, ``recovering``, ``pending_recovery``, ``suspect``, ``offline`` |
+
 ### sqlserver.database.io.read_latency
 
 Total time that the users waited for reads issued on this file.

receiver/sqlserverreceiver/factory.go

@@ -51,6 +51,10 @@ func setupQueries(cfg *Config) []string {
 		queries = append(queries, getSQLServerPerformanceCounterQuery(cfg.InstanceName))
 	}
 
+	if cfg.MetricsBuilderConfig.Metrics.SqlserverDatabaseCount.Enabled {
+		queries = append(queries, getSQLServerPropertiesQuery(cfg.InstanceName))
+	}
+
 	return queries
 }
 

receiver/sqlserverreceiver/internal/metadata/testdata/config.yaml

@@ -7,6 +7,8 @@ all_set:
       enabled: true
     sqlserver.batch.sql_recompilation.rate:
       enabled: true
+    sqlserver.database.count:
+      enabled: true
     sqlserver.database.io.read_latency:
       enabled: true
     sqlserver.lock.wait.rate:
@@ -64,6 +66,8 @@ none_set:
       enabled: false
     sqlserver.batch.sql_recompilation.rate:
       enabled: false
+    sqlserver.database.count:
+      enabled: false
     sqlserver.database.io.read_latency:
       enabled: false
     sqlserver.lock.wait.rate:

receiver/sqlserverreceiver/metadata.yaml

@@ -39,6 +39,10 @@ attributes:
   file_type:
     description: The type of file being monitored.
     type: string
+  database.status:
+    description: The current status of a database
+    type: string
+    enum: [online, restoring, recovering, pending_recovery, suspect, offline]
 
 metrics:
   sqlserver.user.connection.count:
@@ -222,6 +226,15 @@ metrics:
       input_type: string
     attributes: []
     extended_documentation: This metric is only available when the receiver is configured to directly connect to SQL Server.
+  sqlserver.database.count:
+    enabled: false
+    description: The number of databases
+    unit: "{databases}"
+    gauge:
+      value_type: int
+      input_type: string
+    attributes: [database.status]
+    extended_documentation: This metric is only available when the receiver is configured to directly connect to SQL Server.
 
 tests:
   config: