Extended preflight check, added logging and adapted state machine transitions (#15149)

* Extended preflight check, added logging and adapted state machine transitions

* fixed opensearch preflight check

* fixed opensearch preflight check, add tests

data-node/src/test/java/org/graylog/datanode/bootstrap/OpensearchBinPreflightCheckTest.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2020 Graylog, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ */
+package org.graylog.datanode.bootstrap;
+
+import org.assertj.core.api.Assertions;
+import org.graylog2.bootstrap.preflight.PreflightCheckException;
+import org.graylog2.shared.utilities.StringUtils;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.PosixFilePermission;
+import java.util.Collections;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class OpensearchBinPreflightCheckTest {
+
+    @TempDir
+    private Path tempDir;
+
+    @Test
+    void testNonexistentDirectory() {
+        final Path baseDirectory = tempDir.resolve("nonexistent");
+        final OpensearchBinPreflightCheck check = new OpensearchBinPreflightCheck(baseDirectory);
+        Assertions.assertThatThrownBy(check::runCheck)
+                .isInstanceOf(PreflightCheckException.class)
+                .hasMessage("Opensearch base directory %s doesn't exist!", baseDirectory.toAbsolutePath());
+    }
+
+
+    @Test
+    void testNonexistentBinary() throws IOException {
+        final Path baseDir = tempDir.resolve("opensearch");
+        final Path binDir = baseDir.resolve("bin");
+        Files.createDirectories(binDir);
+
+        // nonexistent!
+        final Path executable = binDir.resolve("opensearch");
+
+        final OpensearchBinPreflightCheck check = new OpensearchBinPreflightCheck(baseDir);
+
+        Assertions.assertThatThrownBy(check::runCheck)
+                .isInstanceOf(PreflightCheckException.class)
+                .hasMessage("Opensearch binary %s doesn't exist!", executable.toAbsolutePath());
+    }
+
+    @Test
+    void testBinaryWithoutExecPermission() throws IOException {
+        final Path baseDir = tempDir.resolve("opensearch");
+        final Path binDir = baseDir.resolve("bin");
+        Files.createDirectories(binDir);
+        final Path executable = binDir.resolve("opensearch");
+        Files.createFile(executable);
+
+        final OpensearchBinPreflightCheck check = new OpensearchBinPreflightCheck(baseDir);
+        Assertions.assertThatThrownBy(check::runCheck)
+                .isInstanceOf(PreflightCheckException.class)
+                .hasMessageStartingWith(StringUtils.f("Opensearch binary %s is not executable!", executable.toAbsolutePath()));
+    }
+
+
+    @Test
+    void testBinaryOk() throws IOException {
+        final Path baseDir = tempDir.resolve("opensearch");
+        final Path binDir = baseDir.resolve("bin");
+        Files.createDirectories(binDir);
+        final Path executable = binDir.resolve("opensearch");
+        Files.createFile(executable);
+       Files.setPosixFilePermissions(executable, Collections.singleton(PosixFilePermission.OWNER_EXECUTE));
+
+
+        final OpensearchBinPreflightCheck check = new OpensearchBinPreflightCheck(baseDir);
+        Assertions.assertThatCode(check::runCheck)
+                .doesNotThrowAnyException();
+    }
+}
+