Implement mysql_databases data source (petoju#160)

Author: hfm

mysql/data_source_databases.go

@@ -0,0 +1,70 @@
+package mysql
+
+import (
+	"context"
+	"fmt"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
+	"log"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/id"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+)
+
+func dataSourceDatabases() *schema.Resource {
+	return &schema.Resource{
+		ReadContext: ShowDatabases,
+		Schema: map[string]*schema.Schema{
+			"pattern": {
+				Type:     schema.TypeString,
+				Optional: true,
+			},
+			"databases": {
+				Type:     schema.TypeList,
+				Computed: true,
+				Elem:     &schema.Schema{Type: schema.TypeString},
+			},
+		},
+	}
+}
+
+func ShowDatabases(ctx context.Context, d *schema.ResourceData, meta interface{}) diag.Diagnostics {
+	db, err := getDatabaseFromMeta(ctx, meta)
+	if err != nil {
+		return diag.FromErr(err)
+	}
+
+	pattern := d.Get("pattern").(string)
+
+	sql := fmt.Sprint("SHOW DATABASES")
+
+	if pattern != "" {
+		sql += fmt.Sprintf(" LIKE '%s'", pattern)
+	}
+
+	log.Printf("[DEBUG] SQL: %s", sql)
+
+	rows, err := db.QueryContext(ctx, sql)
+	if err != nil {
+		return diag.Errorf("failed querying for databases: %v", err)
+	}
+	defer rows.Close()
+
+	var databases []string
+	for rows.Next() {
+		var database string
+
+		if err := rows.Scan(&database); err != nil {
+			return diag.Errorf("failed scanning MySQL rows: %v", err)
+		}
+
+		databases = append(databases, database)
+	}
+
+	if err := d.Set("databases", databases); err != nil {
+		return diag.Errorf("failed setting databases field: %v", err)
+	}
+
+	d.SetId(id.UniqueId())
+
+	return nil
+}

mysql/data_source_databases_test.go

@@ -0,0 +1,76 @@
+package mysql
+
+import (
+	"fmt"
+	"strconv"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
+)
+
+func TestAccDataSourceDatabases(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:          func() { testAccPreCheck(t) },
+		ProviderFactories: testAccProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccDatabasesConfigBasic("%"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("data.mysql_databases.test", "pattern", "%"),
+					testAccDatabasesCount("data.mysql_databases.test", "databases.#", func(rn string, databaseCount int) error {
+						if databaseCount < 1 {
+							return fmt.Errorf("%s: databases not found", rn)
+						}
+
+						return nil
+					}),
+				),
+			},
+			{
+				Config: testAccDatabasesConfigBasic("__database_does_not_exist__"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("data.mysql_databases.test", "pattern", "__database_does_not_exist__"),
+					testAccDatabasesCount("data.mysql_databases.test", "databases.#", func(rn string, databaseCount int) error {
+						if databaseCount > 0 {
+							return fmt.Errorf("%s: unexpected database found", rn)
+						}
+
+						return nil
+					}),
+				),
+			},
+		},
+	})
+}
+
+func testAccDatabasesCount(rn string, key string, check func(string, int) error) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[rn]
+
+		if !ok {
+			return fmt.Errorf("resource not found: %s", rn)
+		}
+
+		value, ok := rs.Primary.Attributes[key]
+
+		if !ok {
+			return fmt.Errorf("%s: attribute '%s' not found", rn, key)
+		}
+
+		databaseCount, err := strconv.Atoi(value)
+
+		if err != nil {
+			return err
+		}
+
+		return check(rn, databaseCount)
+	}
+}
+
+func testAccDatabasesConfigBasic(pattern string) string {
+	return fmt.Sprintf(`
+data "mysql_databases" "test" {
+		pattern = "%s"
+}`, pattern)
+}

mysql/provider.go

@@ -241,7 +241,8 @@ func Provider() *schema.Provider {
 		},
 
 		DataSourcesMap: map[string]*schema.Resource{
-			"mysql_tables": dataSourceTables(),
+			"mysql_databases": dataSourceDatabases(),
+			"mysql_tables":    dataSourceTables(),
 		},
 
 		ResourcesMap: map[string]*schema.Resource{

website/docs/d/databases.html.markdown

@@ -0,0 +1,32 @@
+---
+layout: "mysql"
+page_title: "MySQL: mysql_databases"
+sidebar_current: "docs-mysql-datasource-databases"
+description: |-
+  Gets databases on a MySQL server.
+---
+
+# Data Source: mysql\_databases
+
+The ``mysql_databases`` gets databases on a MySQL
+server.
+
+## Example Usage
+
+```hcl
+data "mysql_databases" "app" {
+  pattern = "test_%"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `pattern` - (Optional) Patterns for searching databases.
+
+## Attributes Reference
+
+The following attributes are exported:
+
+* `databases` - The list of the database names.

website/mysql.erb

@@ -40,6 +40,10 @@
           <a href="#">Data Sources</a>
           <ul class="nav nav-visible">
 
+            <li<%= sidebar_current("docs-mysql-datasource-databases") %>>
+              <a href="/docs/providers/mysql/d/databases.html">mysql_databases</a>
+            </li>
+
             <li<%= sidebar_current("docs-mysql-datasource-tables") %>>
               <a href="/docs/providers/mysql/d/tables.html">mysql_tables</a>
             </li>