fix(CsvFileWriter): truncate existing files

pom.xml

@@ -1,5 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
 
   <name>Zeebe CSV Exporter</name>
@@ -13,7 +15,7 @@
     <artifactId>camunda-release-parent</artifactId>
     <version>2.5</version>
     <!-- do not remove empty tag - http://jira.codehaus.org/browse/MNG-4687 -->
-    <relativePath />
+    <relativePath/>
   </parent>
 
   <licenses>
@@ -52,6 +54,7 @@
     <plugin.version.fmt>2.6.0</plugin.version.fmt>
     <plugin.version.license>3.0</plugin.version.license>
     <plugin.version.shade>3.2.1</plugin.version.shade>
+    <plugin.version.surefire>3.0.0-M3</plugin.version.surefire>
   </properties>
 
   <dependencies>
@@ -154,6 +157,17 @@
         </executions>
       </plugin>
 
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>${plugin.version.surefire}</version>
+        <configuration>
+          <failIfNoTests>false</failIfNoTests>
+          <trimStackTrace>false</trimStackTrace>
+          <redirectTestOutputToFile>true</redirectTestOutputToFile>
+        </configuration>
+      </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-failsafe-plugin</artifactId>

src/main/java/io/zeebe/exporter/writer/CsvFileWriter.java

@@ -21,11 +21,12 @@
 import com.fasterxml.jackson.dataformat.csv.CsvSchema;
 import io.zeebe.exporter.record.CsvRecord;
 import java.io.BufferedWriter;
-import java.io.File;
-import java.io.FileWriter;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
+import java.nio.file.OpenOption;
 import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
 
 public class CsvFileWriter implements CsvWriter {
 
@@ -47,8 +48,11 @@ public CsvFileWriter(Path output, String prefix, Class schemaClass) {
   public void write(CsvRecord record) throws IOException {
     if (sequenceWriter == null) {
       Path path = filePath(output, prefix, record.getPartition());
-      File file = Files.createFile(path).toFile();
-      sequenceWriter = objectWriter.writeValues(new BufferedWriter(new FileWriter(file)));
+      OpenOption openOption =
+          Files.exists(path) ? StandardOpenOption.TRUNCATE_EXISTING : StandardOpenOption.CREATE_NEW;
+      BufferedWriter bufferedWriter =
+          Files.newBufferedWriter(path, StandardCharsets.UTF_8, openOption);
+      sequenceWriter = objectWriter.writeValues(bufferedWriter);
     }
 
     sequenceWriter.write(record);

src/test/java/io/zeebe/exporter/CsvFileWriterTest.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright © 2019 camunda services GmbH ([email protected])
+ *
+ * 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 io.zeebe.exporter;
+
+import io.zeebe.exporter.record.JobCsvRecord;
+import io.zeebe.exporter.writer.CsvFileWriter;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.function.Supplier;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+public class CsvFileWriterTest {
+
+  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+  @Test
+  public void shouldOverwriteExistingFile() throws IOException {
+    // given
+    Path path = temporaryFolder.getRoot().toPath();
+    Supplier<CsvFileWriter> writerFactory =
+        () -> new CsvFileWriter(path, "test", JobCsvRecord.class);
+
+    writerFactory.get().write(new JobCsvRecord());
+
+    // when then is no exception thrown
+    writerFactory.get().write(new JobCsvRecord());
+  }
+}