1 files changed, 80 insertions, 0 deletions
diff --git a/src/main/java/org/onap/sdc/helmvalidator/helm/versions/ApiVersionsReader.java b/src/main/java/org/onap/sdc/helmvalidator/helm/versions/ApiVersionsReader.java
new file mode 100644
index 0000000..e5c1a2e
--- /dev/null
+++ b/src/main/java/org/onap/sdc/helmvalidator/helm/versions/ApiVersionsReader.java
@@ -0,0 +1,80 @@
+/*
+ * ============LICENSE_START=======================================================
+ * SDC-HELM-VALIDATOR
+ * ================================================================================
+ * Copyright (C) 2021 Nokia. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.sdc.helmvalidator.helm.versions;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.nio.file.Path;
+import java.util.Optional;
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
+import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
+import org.apache.commons.compress.compressors.gzip.GzipCompressorInputStream;
+import org.onap.sdc.helmvalidator.helm.versions.exception.ApiVersionNotFoundException;
+import org.onap.sdc.helmvalidator.helm.versions.exception.ReadFileException;
+import org.springframework.stereotype.Service;
+
+@Service
+public class ApiVersionsReader {
+
+    private static final int MAIN_CHART_DIR_DEPTH = 2;
+    private static final String API_VERSION_PREFIX = "apiVersion:";
+    private static final Path CHART_FILE_NAME = Path.of("Chart.yaml");
+
+    String readVersion(String chartPath) {
+        return tryReadVersionFromChart(chartPath)
+            .orElseThrow(ApiVersionNotFoundException::new);
+    }
+
+    private Optional<String> tryReadVersionFromChart(String chartPath) {
+        try (TarArchiveInputStream tarInput = new TarArchiveInputStream(
+            new GzipCompressorInputStream(new FileInputStream(chartPath)))) {
+            return readVersionFromChart(tarInput);
+        } catch (IOException e) {
+            throw new ReadFileException("Cannot read tar from path: " + chartPath, e);
+        }
+    }
+
+    private Optional<String> readVersionFromChart(TarArchiveInputStream tarInput) throws IOException {
+        TarArchiveEntry currentEntry;
+        while ((currentEntry = tarInput.getNextTarEntry()) != null) {
+            if (isMainChartYaml(currentEntry)) {
+                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(tarInput));
+                return bufferedReader.lines()
+                    .filter(chartLine -> chartLine.contains(API_VERSION_PREFIX))
+                    .map(apiVersionLine -> apiVersionLine.replaceAll(API_VERSION_PREFIX, ""))
+                    .map(String::trim)
+                    .findFirst();
+            }
+        }
+        return Optional.empty();
+    }
+
+    private boolean isMainChartYaml(TarArchiveEntry currentEntry) {
+        Path entryPath = Path.of(currentEntry.getName());
+        return currentEntry.isFile()
+            && CHART_FILE_NAME.equals(entryPath.getFileName())
+            && (entryPath.getNameCount() == MAIN_CHART_DIR_DEPTH);
+    }
+
+
+}