Fail SQL gracefully if no python dependencies installed

python/pom.xml

@@ -37,7 +37,7 @@
     <py4j.version>0.9.2</py4j.version>
     <python.test.exclude>
         **/PythonInterpreterWithPythonInstalledTest.java,
-        **/PythonPandasSqlInterpreterTest.java
+        **/PythonInterpreterPandasSqlTest.java
     </python.test.exclude>
   </properties>
 

python/src/main/java/org/apache/zeppelin/python/PythonInterpreter.java

@@ -204,15 +204,20 @@ public class PythonInterpreter extends Interpreter {
   }
 
 
-  private String sendCommandToPython(String cmd) {
+  /**
+   * Sends given text to Python interpreter, blocks and returns the output
+   * @param cmd Python expression text
+   * @return output
+   */
+  String sendCommandToPython(String cmd) {
     String output = "";
-    LOG.info("Sending : \n" + (cmd.length() > 200 ? cmd.substring(0, 200) + "..." : cmd));
+    LOG.debug("Sending : \n" + (cmd.length() > 200 ? cmd.substring(0, 200) + "..." : cmd));
     try {
       output = process.sendAndGetResult(cmd);
     } catch (IOException e) {
       LOG.error("Error when sending commands to python process", e);
     }
-    //logger.info("Got : \n" + output);
+    LOG.debug("Got : \n" + output);
     return output;
   }
 
@@ -243,11 +248,7 @@ public class PythonInterpreter extends Interpreter {
 
   public Boolean isPy4jInstalled() {
     String output = sendCommandToPython("\n\nimport py4j\n");
-    if (output.contains("ImportError")) {
-      return false;
-    } else {
-      return true;
-    }
+    return !output.contains("ImportError");
   }
 
   private int findRandomOpenPortOnAllLocalInterfaces() {

python/src/main/java/org/apache/zeppelin/python/PythonInterpreterPandasSql.java

@@ -33,16 +33,16 @@ import org.slf4j.LoggerFactory;
  *
  * Match experience of %sparpk.sql over Spark DataFrame
  */
-public class PythonPandasSqlInterpreter extends Interpreter {
-  private static final Logger LOG = LoggerFactory.getLogger(PythonPandasSqlInterpreter.class);
+public class PythonInterpreterPandasSql extends Interpreter {
+  private static final Logger LOG = LoggerFactory.getLogger(PythonInterpreterPandasSql.class);
 
   private String SQL_BOOTSTRAP_FILE_PY = "/bootstrap_sql.py";
 
-  public PythonPandasSqlInterpreter(Properties property) {
+  public PythonInterpreterPandasSql(Properties property) {
     super(property);
   }
 
-  private PythonInterpreter getPythonInterpreter() {
+  PythonInterpreter getPythonInterpreter() {
     LazyOpenInterpreter lazy = null;
     PythonInterpreter python = null;
     Interpreter p = getInterpreterInTheSameSessionByClassName(PythonInterpreter.class.getName());
@@ -64,9 +64,6 @@ public class PythonPandasSqlInterpreter extends Interpreter {
   @Override
   public void open() {
     LOG.info("Open Python SQL interpreter instance: {}", this.toString());
-
-  //TODO(bzz): check i.e by importing and catching ImportError
-  //if (py4jAndPandasAndPandasqlAreInstalled) {
     try {
       LOG.info("Bootstrap {} interpreter with {}", this.toString(), SQL_BOOTSTRAP_FILE_PY);
       PythonInterpreter python = getPythonInterpreter();
@@ -74,7 +71,16 @@ public class PythonPandasSqlInterpreter extends Interpreter {
     } catch (IOException e) {
       LOG.error("Can't execute " + SQL_BOOTSTRAP_FILE_PY + " to import SQL dependencies", e);
     }
-  //}
+  }
+
+  /**
+   * Checks if Python dependencies pandas and pandasql are installed
+   * @return True if they are
+   */
+  boolean isPandasAndPandasqlInstalled() {
+    PythonInterpreter python = getPythonInterpreter();
+    String output = python.sendCommandToPython("\n\nimport pandas\nimport pandasql\n");
+    return !output.contains("ImportError");
   }
 
   @Override

python/src/main/resources/bootstrap.py

@@ -132,6 +132,8 @@ class PyZeppelinContext(object):
             # `isinstance(p, DataFrame)` would req `import pandas.core.frame.DataFrame`
             # and so a dependency on pandas
             self.show_dataframe(p, **kwargs)
+        elif hasattr(p, '__call__'):
+            p() #error reporting
     
     def show_dataframe(self, df, **kwargs):
         """Pretty prints DF using Table Display System

python/src/main/resources/bootstrap_sql.py

@@ -13,15 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# This is for org.apache.zeppelin.python.PythonPandasSqlInterpreterTest
+# Setup SQL over Pandas DataFrames
 # It requires next dependencies to be installed:
-#  - numpy
 #  - pandas
 #  - pandasql
 
+from __future__ import print_function
 
-import numpy as np
-import pandas as pd
-from pandasql import sqldf
-
-pysqldf = lambda q: sqldf(q, globals())
+try:
+    from pandasql import sqldf
+    pysqldf = lambda q: sqldf(q, globals())
+except ImportError:
+    pysqldf = lambda q: print("Can not run SQL over Pandas DataFrame" +
+                              "Make sure 'pandas' and 'pandasql' libraries are installed")

python/src/test/java/org/apache/zeppelin/python/PythonInterpreterPandasSqlTest.java

@@ -44,7 +44,8 @@ import org.junit.Test;
  * <ol>
  *  - <li>Python</li>
  *  - <li>NumPy</li>
- *  - <li>Pandas DataFrame</li>
+ *  - <li>Pandas</li>
+ *  - <li>PandaSql</li>
  * <ol>
  *
  * To run manually on such environment, use:
@@ -52,10 +53,10 @@ import org.junit.Test;
  *   mvn -Dpython.test.exclude='' test -pl python -am
  * </code>
  */
-public class PythonPandasSqlInterpreterTest {
+public class PythonInterpreterPandasSqlTest {
 
   private InterpreterGroup intpGroup;
-  private PythonPandasSqlInterpreter sql;
+  private PythonInterpreterPandasSql sql;
   private PythonInterpreter python;
 
   private InterpreterContext context;
@@ -72,7 +73,7 @@ public class PythonPandasSqlInterpreterTest {
     python.setInterpreterGroup(intpGroup);
     python.open();
 
-    sql = new PythonPandasSqlInterpreter(p);
+    sql = new PythonInterpreterPandasSql(p);
     sql.setInterpreterGroup(intpGroup);
 
     intpGroup.put("note", Arrays.asList(python, sql));
@@ -92,23 +93,47 @@ public class PythonPandasSqlInterpreterTest {
   }
 
   @Test
-  public void sqlOverTestDataPrintsTable() {
-    //given
-    // `import pandas as pd` and `import numpy as np` done
-    // DataFrame \w test data
-    String expectedTable = "name\tage\n\nmoon\t33\n\npark\t34";
-    python.interpret("df2 = pd.DataFrame({ 'age'  : np.array([33, 51, 51, 34]), "+
-                                          "'name' : pd.Categorical(['moon','jobs','gates','park'])})", context);
+  public void dependenciesAreInstalled() {
+    InterpreterResult ret = python.interpret("import pandas\nimport pandasql\nimport numpy\n", context);
+    assertEquals(ret.message(), InterpreterResult.Code.SUCCESS, ret.code());
+  }
 
+  @Test
+  public void errorMessageIfDependenciesNotInstalled() {
+    InterpreterResult ret;
+    // given
+    ret = python.interpret(
+        "pysqldf = lambda q: print('Can not execute SQL as Python dependency is not installed')",
+         context);
+    assertEquals(ret.message(), InterpreterResult.Code.SUCCESS, ret.code());
+
+    // when
+    ret = sql.interpret("SELECT * from something", context);
+
+    // then
+    assertNotNull(ret);
+    assertEquals(ret.message(), InterpreterResult.Code.SUCCESS, ret.code());
+    assertTrue(ret.message().contains("dependency is not installed"));
+  }
+
+  @Test
+  public void sqlOverTestDataPrintsTable() {
+    InterpreterResult ret;
+    // given
+    //String expectedTable = "name\tage\n\nmoon\t33\n\npark\t34";
+    ret = python.interpret("import pandas as pd", context);
+    ret = python.interpret("import numpy as np", context);
+    // DataFrame df2 \w test data
+    ret = python.interpret("df2 = pd.DataFrame({ 'age'  : np.array([33, 51, 51, 34]), "+
+                           "'name' : pd.Categorical(['moon','jobs','gates','park'])})", context);
+    assertEquals(ret.message(), InterpreterResult.Code.SUCCESS, ret.code());
 
     //when
-    InterpreterResult ret = sql.interpret("select name, age from df2 where age < 40", context);
+    ret = sql.interpret("select name, age from df2 where age < 40", context);
 
     //then
-    assertEquals(InterpreterResult.Code.SUCCESS, ret.code());
-    assertEquals(Type.TABLE, ret.type());
-    //System.out.println(ret.message());
-    //System.out.println(expectedTable);
+    assertEquals(ret.message(), InterpreterResult.Code.SUCCESS, ret.code());
+    assertEquals(ret.message(), Type.TABLE, ret.type());
     //assertEquals(expectedTable, ret.message()); //somehow it's same but not equal
     assertTrue(ret.message().indexOf("moon\t33") > 0);
     assertTrue(ret.message().indexOf("park\t34") > 0);
@@ -124,9 +149,8 @@ public class PythonPandasSqlInterpreterTest {
     //then
     assertNotNull("Interpreter returned 'null'", ret);
     //System.out.println("\nInterpreter response: \n" + ret.message());
-    assertEquals(InterpreterResult.Code.ERROR, ret.code());
+    assertEquals(ret.toString(), InterpreterResult.Code.ERROR, ret.code());
     assertTrue(ret.message().length() > 0);
   }
 
-
 }

python/src/test/java/org/apache/zeppelin/python/PythonInterpreterTest.java

@@ -187,7 +187,7 @@ public class PythonInterpreterTest {
       s.connect(sa, 10000);
       connected = true;
     } catch (IOException e) {
-      LOG.error("Can't open connection to " + sa, e);
+      //LOG.warn("Can't open connection to " + sa, e);
     }
     return connected;
   }

python/src/test/java/org/apache/zeppelin/python/PythonInterpreterWithPythonInstalledTest.java

@@ -36,7 +36,7 @@ import org.junit.Test;
  *
  * or
  * <code>
- * mvn -Dpython.test.exclude='' test -pl python
+ * mvn -Dpython.test.exclude='' test -pl python -am
  * </code>
  */
 public class PythonInterpreterWithPythonInstalledTest {