smiklosovic commented on code in PR #2842: URL: https://github.com/apache/cassandra/pull/2842#discussion_r1440328178
########## src/java/org/apache/cassandra/utils/SystemInfo.java: ########## @@ -0,0 +1,223 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.cassandra.utils; + +import java.util.List; +import java.util.Optional; +import java.util.function.Supplier; +import java.util.regex.Pattern; + +import com.vdurmont.semver4j.Semver; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.io.util.File; +import org.apache.cassandra.io.util.FileUtils; +import oshi.PlatformEnum; + +import static java.lang.String.format; +import static java.util.Optional.empty; +import static java.util.Optional.of; + +/** + * An abstraction of System information, this class provides access to system information without specifying how + * it is retrieved. + */ +public final class SystemInfo +{ + // TODO: Determine memlock limits if possible + // TODO: Determine if file system is remote or local + // TODO: Determine if disk latency is within acceptable limits + + private static final Logger logger = LoggerFactory.getLogger(SystemInfo.class); + + private static final long INFINITY = -1L; + private static final long EXPECTED_MIN_NOFILE = 10000L; // number of files that can be opened + private static final long EXPECTED_NPROC = 32768L; // number of processes + private static final long EXPECTED_AS = 0x7FFFFFFFL; // address space + + /** + * The default number of processes that are reported if the actual value can not be retrieved. + */ + private static final long DEFAULT_MAX_PROCESSES = 1024; + + private static final Pattern SPACES_PATTERN = Pattern.compile("\\s+"); + + /** + * The oshi.SystemInfo has the following note: + * Platform-specific Hardware and Software objects are retrieved via memoized suppliers. To conserve memory at the + * cost of additional processing time, create a new version of SystemInfo() for subsequent calls. To conserve + * processing time at the cost of additional memory usage, re-use the same {@link SystemInfo} object for future + * queries. + * <p> + * We are opting for minimal memory footprint. + */ + private final oshi.SystemInfo si; + + public SystemInfo() + { + si = new oshi.SystemInfo(); + } + + /** + * @return The name of the current platform. (e.g. Linux) + */ + public String platform() + { + return oshi.SystemInfo.getCurrentPlatform().name(); + } + + /** + * Gets the maximum number of processes the user can create. + * Note: if not on a Linux system this always return the + * + * @return The maximum number of processes. + * @see #DEFAULT_MAX_PROCESSES + */ + public long getMaxProcess() + { + // this check only works on Linux systems. Errors fall through to return default. + if (oshi.SystemInfo.getCurrentPlatform() == PlatformEnum.LINUX) + { + String path = format("/proc/%s/limits", getPid()); + try + { + List<String> lines = FileUtils.readLines(new File(path)); + for (String line : lines) + { + if (line.startsWith("Max processes")) + { + String[] parts = SPACES_PATTERN.split(line); + + if (parts.length < 3) + continue; + + String limit = parts[2]; + return "unlimited".equals(limit) ? INFINITY : Long.parseLong(limit); + } + } + logger.error( "'Max processes' not found in "+path); + } + catch (Throwable t) + { + logger.error(format("Unable to read %s", path), t); + } + } + + /* return the default value for non-Linux systems or parsing error. + * Can not return 0 as we know there is at least 1 process (this one) and + * -1 historically represents infinity. + */ + return DEFAULT_MAX_PROCESSES; + } + + /** + * @return The maximum number of open files allowd to the current process/user. + */ + public long getMaxOpenFiles() + { + // ulimit -H -n + return si.getOperatingSystem().getCurrentProcess().getHardOpenFileLimit(); + } + + /** + * Gets the Virtual Memory Size (VSZ). Includes all memory that the process can access, + * including memory that is swapped out and memory that is from shared libraries. + * + * @return The amount of virtual memory allowed to be allocatedby the current process/user. + */ + public long getVirtualMemoryMax() + { + return si.getOperatingSystem().getCurrentProcess().getVirtualSize(); + } + + /** + * @return The amount of swap space allocated on the system. + */ + public long getSwapSize() + { + return si.getHardware().getMemory().getVirtualMemory().getSwapTotal(); + } + + /** + * @return the PID of the current system. + */ + public long getPid() + { + return si.getOperatingSystem().getProcessId(); + } + + /** + * @return the Semver for the kernel version of the OS. + */ + public Semver getKernelVersion() + { + return new Semver(si.getOperatingSystem().getVersionInfo().getBuildNumber(), Semver.SemverType.LOOSE); + } + + /** + * Tests if the system is running in degraded mode. + * + * @return non-empty optional with degradation messages if the system is in degraded mode, empty optional otherwise. + */ + public Optional<String> isDegraded() Review Comment: @Claudenw I was thinking about adding some tests for this. As of now, we just don't test the logic in this method. SystemInfo might be mocked by Mockito on its methods to return whatever we want instead of oshi returning it and then we could make assertions on various corner cases and values so we might watch what degradation string we resolve here. Another option is to not use Mockito but we might just extend this class and override its methods, returning whatever we want. Then we might do assertions on `isDegraded` output. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
