Use query builder for Teradata dbcinfo query (#314)

Author: dawidxc

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/TeradataLogsConnector.java

@@ -65,6 +65,8 @@ public class TeradataLogsConnector extends AbstractTeradataConnector
 
   private static final Logger LOG = LoggerFactory.getLogger(TeradataLogsConnector.class);
   private static final String ASSESSMENT_DEF_LOG_TABLE = "dbc.QryLogV";
+
+  /** The length of the VARCHAR column {@code DBQLSqlTbl.SQLTextInfo}. */
   static final int DBQLSQLTBL_SQLTEXTINFO_LENGTH = 31000;
 
   private static final Range<Long> MAX_SQL_LENGTH_RANGE =
@@ -93,7 +95,9 @@ public enum TeradataLogsConnectorProperty implements ConnectorProperty {
         "max-sql-length",
         "Max length of the DBQLSqlTbl.SqlTextInfo column."
             + " Text that is longer than the defined limit will be split into multiple rows."
-            + " Example: 10000. Allowed range: 5000-30000.",
+            + " Example: 10000. Allowed range: "
+            + MAX_SQL_LENGTH_RANGE
+            + ".",
         /* defaultValue= */ null);
 
     private final String name;

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/TeradataMetadataConnector.java

@@ -18,6 +18,10 @@
 
 import static com.google.edwmigration.dumper.application.dumper.connector.teradata.TeradataUtils.formatQuery;
 import static com.google.edwmigration.dumper.application.dumper.connector.teradata.TeradataUtils.optionalIf;
+import static com.google.edwmigration.dumper.application.dumper.connector.teradata.query.TeradataSelectBuilder.eq;
+import static com.google.edwmigration.dumper.application.dumper.connector.teradata.query.TeradataSelectBuilder.identifier;
+import static com.google.edwmigration.dumper.application.dumper.connector.teradata.query.TeradataSelectBuilder.stringLiteral;
+import static com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.SelectExpression.select;
 import static java.util.stream.Collectors.joining;
 import static java.util.stream.Collectors.toList;
 
@@ -53,8 +57,11 @@
 public class TeradataMetadataConnector extends AbstractTeradataConnector
     implements MetadataConnector, TeradataMetadataDumpFormat {
 
+  /** The length of the VARCHAR column {@code TableTextV.RequestText}. */
   private static final int TABLE_TEXT_V_REQUEST_TEXT_LENGTH = 32000;
-  private static final Range<Long> MAX_TEXT_LENGTH_RANGE = Range.closed(5000L, 32000L);
+
+  private static final Range<Long> MAX_TEXT_LENGTH_RANGE =
+      Range.closed(5000L, (long) TABLE_TEXT_V_REQUEST_TEXT_LENGTH);
 
   public enum TeradataMetadataConnectorProperties implements ConnectorProperty {
     TABLE_SIZE_V_MAX_ROWS(
@@ -136,10 +143,13 @@ public void addTasksTo(List<? super Task<?>> out, ConnectorArguments arguments)
         new TeradataJdbcSelectTask(
             VersionFormat.ZIP_ENTRY_NAME,
             TaskCategory.OPTIONAL,
-            "SELECT 'teradata' AS dialect, "
-                + "\"InfoData\" AS version, "
-                + "CURRENT_TIMESTAMP as export_time"
-                + " from dbc.dbcinfo where \"InfoKey\" = 'VERSION';"));
+            select(
+                    stringLiteral("teradata").as("dialect"),
+                    identifier("InfoData").as("version"),
+                    identifier("CURRENT_TIMESTAMP").as("export_time"))
+                .from("dbc.dbcinfo")
+                .where(eq(identifier("InfoKey"), stringLiteral("VERSION")))
+                .serialize()));
 
     // This is theoretically more reliable than ColumnsV, but if we are bandwidth limited, we should
     // risk taking ColumnsV only.

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/TeradataUtils.java

@@ -42,7 +42,7 @@ public static <T> Optional<T> optionalIf(boolean condition, Supplier<T> supplier
    * query contains string literals with whitespace, they will be modified, which might be
    * undesirable. This method should not be used in such cases.
    */
-  static String formatQuery(String query) {
+  public static String formatQuery(String query) {
     return query.replaceAll("\\s+", " ").replaceAll("\\( ", "(").replaceAll(" \\)", ")").trim();
   }
 

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/ExpressionSerializer.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query;
+
+import com.google.common.collect.ImmutableList;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.BinaryExpression;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Expression;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Identifier;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Projection;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.SelectExpression;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.SourceSpec;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.StringLiteral;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.TableSourceSpec;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public class ExpressionSerializer {
+
+  private final Expression expression;
+  private StringBuilder serializedQuery = new StringBuilder();
+
+  ExpressionSerializer(Expression expression) {
+    this.expression = expression;
+  }
+
+  public static String serialize(Expression expression) {
+    return new ExpressionSerializer(expression).serialize();
+  }
+
+  String serialize() {
+    serializedQuery = new StringBuilder();
+    append(expression);
+    return serializedQuery.toString();
+  }
+
+  private void append(Expression expr) {
+    if (expr instanceof SelectExpression) {
+      append((SelectExpression) expression);
+    } else if (expr instanceof StringLiteral) {
+      serializedQuery.append(escapeStringLiteral(((StringLiteral) expr).value()));
+    } else if (expr instanceof Identifier) {
+      serializedQuery.append(((Identifier) expr).name());
+    } else if (expr instanceof BinaryExpression) {
+      append(((BinaryExpression) expr));
+    } else {
+      throw new IllegalArgumentException(String.format("Unsupported expression type: '%s'.", expr));
+    }
+  }
+
+  private void append(BinaryExpression expr) {
+    appendSpaceIfNecessary();
+    append(expr.lhs());
+    serializedQuery.append(' ');
+    serializedQuery.append(expr.operator());
+    serializedQuery.append(' ');
+    append(expr.rhs());
+  }
+
+  private void append(SelectExpression selectExpression) {
+    serializedQuery.append("SELECT");
+    appendCommaSeparated(selectExpression.projections(), this::append);
+    selectExpression
+        .sourceSpec()
+        .ifPresent(
+            sourceSpec -> {
+              serializedQuery.append(" FROM");
+              append(sourceSpec);
+            });
+    selectExpression
+        .whereCondition()
+        .ifPresent(
+            condition -> {
+              serializedQuery.append(" WHERE");
+              append(condition);
+            });
+  }
+
+  private void append(SourceSpec sourceSpec) {
+    if (sourceSpec instanceof TableSourceSpec) {
+      append((TableSourceSpec) sourceSpec);
+    } else {
+      throw new IllegalStateException(String.format("Unsupported source spec='%s'.", sourceSpec));
+    }
+  }
+
+  private void append(TableSourceSpec tableSourceSpec) {
+    serializedQuery.append(' ');
+    append(tableSourceSpec.tableName());
+    append(tableSourceSpec.alias());
+  }
+
+  private void append(Projection projection) {
+    append(projection.expression());
+    append(projection.alias());
+  }
+
+  private void append(Optional<String> aliasMaybe) {
+    aliasMaybe.ifPresent(alias -> serializedQuery.append(" AS ").append(alias));
+  }
+
+  private void appendSpaceIfNecessary() {
+    if (serializedQuery.length() > 0) {
+      serializedQuery.append(' ');
+    }
+  }
+
+  private <T> void appendCommaSeparated(ImmutableList<T> list, Consumer<T> appender) {
+    boolean first = true;
+    for (T element : list) {
+      if (first) {
+        first = false;
+      } else {
+        serializedQuery.append(',');
+      }
+      serializedQuery.append(' ');
+      appender.accept(element);
+    }
+  }
+
+  private static String escapeStringLiteral(String s) {
+    return "'" + (s.replaceAll("'", "''")) + "'";
+  }
+}

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/TeradataSelectBuilder.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query;
+
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.BinaryExpression;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Expression;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Identifier;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.Projection;
+import com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model.StringLiteral;
+import java.util.Optional;
+
+public class TeradataSelectBuilder {
+
+  public static Identifier identifier(String name) {
+    return Identifier.create(name);
+  }
+
+  public static Projection projection(Expression expression) {
+    return Projection.create(expression, /* alias= */ Optional.empty());
+  }
+
+  public static Projection projection(Expression expression, String alias) {
+    return Projection.create(expression, Optional.of(alias));
+  }
+
+  public static Expression eq(Expression lhs, Expression rhs) {
+    return BinaryExpression.create(lhs, "=", rhs);
+  }
+
+  public static StringLiteral stringLiteral(String value) {
+    return StringLiteral.create(value);
+  }
+}

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/model/BinaryExpression.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model;
+
+import com.google.auto.value.AutoValue;
+
+@AutoValue
+public abstract class BinaryExpression implements Expression {
+  public abstract Expression lhs();
+
+  public abstract String operator();
+
+  public abstract Expression rhs();
+
+  public static BinaryExpression create(Expression lhs, String operator, Expression rhs) {
+    return new AutoValue_BinaryExpression(lhs, operator, rhs);
+  }
+}

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/model/Expression.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model;
+
+import static com.google.edwmigration.dumper.application.dumper.connector.teradata.query.TeradataSelectBuilder.projection;
+
+public interface Expression {
+  default Projection as(String alias) {
+    return projection(this, alias);
+  }
+}

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/model/Identifier.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model;
+
+import com.google.auto.value.AutoValue;
+
+@AutoValue
+public abstract class Identifier implements Expression {
+  public abstract String name();
+
+  public static Identifier create(String name) {
+    return new AutoValue_Identifier(name);
+  }
+}

dumper/app/src/main/java/com/google/edwmigration/dumper/application/dumper/connector/teradata/query/model/Projection.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2022-2023 Google LLC
+ * Copyright 2013-2021 CompilerWorks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.edwmigration.dumper.application.dumper.connector.teradata.query.model;
+
+import com.google.auto.value.AutoValue;
+import java.util.Optional;
+
+@AutoValue
+public abstract class Projection {
+  public abstract Expression expression();
+
+  public abstract Optional<String> alias();
+
+  public static Projection create(Expression expression, Optional<String> alias) {
+    return new AutoValue_Projection(expression, alias);
+  }
+}