Add ability to export rows conditionally. (#7)

* Added Where property to Rules.
* Added example config for excluding non-current revisions of field_body.
* Added where conditions to mtk-dump.

dump/README.md

@@ -20,6 +20,11 @@ rewrite:
     mail: concat(uid, "@localhost")
     pass: '"password"'
 
+where:
+  # Only include body field data for current revisions.
+  node_revision__body: |-
+      revision_id IN (SELECT vid FROM node)
+
 nodata:
   - cache*
   - captcha_sessions

dump/main.go

@@ -88,5 +88,8 @@ func dump(stdout, stderr io.Writer, db *sql.DB, cfg config.Rules) error {
 	// Assign our sanitization rules to the dumper.
 	d.SelectMap = cfg.SanitizeMap()
 
+	// Assign conditional row rules to the dumper.
+	d.WhereMap = cfg.WhereMap()
+
 	return d.Dump(stdout)
 }

dump/pkg/config/config.go

@@ -15,6 +15,7 @@ type Rules struct {
 	Rewrite map[string]Rewrite `yaml:"rewrite" json:"rewrite"`
 	NoData  []string           `yaml:"nodata"  json:"nodata"`
 	Ignore  []string           `yaml:"ignore"  json:"ignore"`
+	Where   map[string]string  `yaml:"where"   json:"where"`
 }
 
 // Rewrite rules for while dumping a database.

dump/pkg/config/config_test.go

@@ -45,6 +45,15 @@ func TestLoad(t *testing.T) {
 				},
 			},
 		},
+		{
+			"where",
+			"test-data/where.yml",
+			Rules{
+				Where: map[string]string{
+					"some_table": "revision_id IN (SELECT revision_id FROM another_table)",
+				},
+			},
+		},
 		{
 			"mixed",
 			"test-data/mixed.yml",
@@ -56,10 +65,12 @@ func TestLoad(t *testing.T) {
 						"qux": "quux",
 					},
 				},
+				Where: map[string]string{
+					"corge": "grault IN (SELECT garply FROM waldo)",
+				},
 			},
 		},
 	}
-
 	for _, testCase := range testCases {
 		actual, err := Load(testCase.config)
 		fmt.Println(actual.SanitizeMap())

dump/pkg/config/test-data/mixed.yml

@@ -5,3 +5,6 @@ nodata:
 rewrite:
   baz:
     qux: quux
+where:
+  corge: |-
+    grault IN (SELECT garply FROM waldo)

dump/pkg/config/test-data/where.yml

@@ -0,0 +1,3 @@
+where:
+  some_table: |-
+    revision_id IN (SELECT revision_id FROM another_table)

dump/pkg/config/utils.go

@@ -10,3 +10,14 @@ func (r Rules) SanitizeMap() map[string]map[string]string {
 
 	return selectMap
 }
+
+// WhereMap list for conditional row exports in the MySQL dump.
+func (r Rules) WhereMap() map[string]string {
+	whereMap := make(map[string]string)
+
+	for table, condition := range r.Where {
+		whereMap[table] = condition
+	}
+
+	return whereMap
+}