/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package jdk.internal.platform.cgroupv1;

import java.io.BufferedReader;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.stream.Stream;

public class Metrics implements jdk.internal.platform.Metrics {

    private SubSystem memory;

    private SubSystem cpu;

    private SubSystem cpuacct;

    private SubSystem cpuset;

    private SubSystem blkio;

    private boolean activeSubSystems;

    // Values returned larger than this number are unlimited.

    static long unlimited_minimum = 0x7FFFFFFFFF000000L;

    private static final Metrics INSTANCE = initContainerSubSystems();

    private static final String PROVIDER_NAME = "cgroupv1";

    private Metrics() {

        activeSubSystems = false;

    }

    public static Metrics getInstance() {

        return INSTANCE;

    }

    private static Metrics initContainerSubSystems() {

        Metrics metrics = new Metrics();

        /**

         * Find the cgroup mount points for subsystems

         * by reading /proc/self/mountinfo

         *

         * Example for docker MemorySubSystem subsystem:

         * 219 214 0:29 /docker/7208cebd00fa5f2e342b1094f7bed87fa25661471a4637118e65f1c995be8a34 /sys/fs/cgroup/MemorySubSystem ro,nosuid,nodev,noexec,relatime - cgroup cgroup rw,MemorySubSystem

         *

         * Example for host:

         * 34 28 0:29 / /sys/fs/cgroup/MemorySubSystem rw,nosuid,nodev,noexec,relatime shared:16 - cgroup cgroup rw,MemorySubSystem

         */

        try (Stream<String> lines =

             Files.lines(Paths.get("/proc/self/mountinfo"))) {

            lines.filter(line -> line.contains(" - cgroup "))

                 .map(line -> line.split(" "))

                 .forEach(entry -> createSubSystem(metrics, entry));

        } catch (IOException e) {

            return null;

        }

        /**

         * Read /proc/self/cgroup and map host mount point to

         * local one via /proc/self/mountinfo content above

         *

         * Docker example:

         * 5:memory:/docker/6558aed8fc662b194323ceab5b964f69cf36b3e8af877a14b80256e93aecb044

         *

         * Host example:

         * 5:memory:/user.slice

         *

         * Construct a path to the process specific memory and cpuset

         * cgroup directory.

         *

         * For a container running under Docker from memory example above

         * the paths would be:

         *

         * /sys/fs/cgroup/memory

         *

         * For a Host from memory example above the path would be:

         *

         * /sys/fs/cgroup/memory/user.slice

         *

         */

        try (Stream<String> lines =

             Files.lines(Paths.get("/proc/self/cgroup"))) {

            lines.map(line -> line.split(":"))

                 .filter(line -> (line.length >= 3))

                 .forEach(line -> setSubSystemPath(metrics, line));

        } catch (IOException e) {

            return null;

        }

        // Return Metrics object if we found any subsystems.

        if (metrics.activeSubSystems()) {

            return metrics;

        }

        return null;

    }

    /**

     * createSubSystem objects and initialize mount points

     */

    private static void createSubSystem(Metrics metric, String [] mountentry) {

        if (mountentry.length < 5) return;

        Path p = Paths.get(mountentry[4]);

        String subsystemName = p.getFileName().toString();

        if (subsystemName != null) {

            switch (subsystemName) {

                case "memory":

                    metric.setMemorySubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                case "cpuset":

                    metric.setCpuSetSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                case "cpu,cpuacct":

                case "cpuacct,cpu":

                    metric.setCpuSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    metric.setCpuAcctSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                case "cpuacct":

                    metric.setCpuAcctSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                case "cpu":

                    metric.setCpuSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                case "blkio":

                    metric.setBlkIOSubSystem(new SubSystem(mountentry[3], mountentry[4]));

                    break;

                default:

                    // Ignore subsystems that we don't support

                    break;

            }

        }

    }

    /**

     * setSubSystemPath based on the contents of /proc/self/cgroup

     */

    private static void setSubSystemPath(Metrics metric, String [] entry) {

        String controller;

        String base;

        SubSystem subsystem = null;

        SubSystem subsystem2 = null;

        controller = entry[1];

        base = entry[2];

        if (controller != null && base != null) {

            switch (controller) {

                case "memory":

                    subsystem = metric.MemorySubSystem();

                    break;

                case "cpuset":

                    subsystem = metric.CpuSetSubSystem();

                    break;

                case "cpu,cpuacct":

                case "cpuacct,cpu":

                    subsystem = metric.CpuSubSystem();

                    subsystem2 = metric.CpuAcctSubSystem();

                    break;

                case "cpuacct":

                    subsystem = metric.CpuAcctSubSystem();

                    break;

                case "cpu":

                    subsystem = metric.CpuSubSystem();

                    break;

                case "blkio":

                    subsystem = metric.BlkIOSubSystem();

                    break;

                // Ignore subsystems that we don't support

                default:

                    break;

            }

        }

        if (subsystem != null) {

            subsystem.setPath(base);

            metric.setActiveSubSystems();

        }

        if (subsystem2 != null) {

            subsystem2.setPath(base);

        }

    }

    private void setActiveSubSystems() {

        activeSubSystems = true;

    }

    private boolean activeSubSystems() {

        return activeSubSystems;

    }

    private void setMemorySubSystem(SubSystem memory) {

        this.memory = memory;

    }

    private void setCpuSubSystem(SubSystem cpu) {

        this.cpu = cpu;

    }

    private void setCpuAcctSubSystem(SubSystem cpuacct) {

        this.cpuacct = cpuacct;

    }

    private void setCpuSetSubSystem(SubSystem cpuset) {

        this.cpuset = cpuset;

    }

    private void setBlkIOSubSystem(SubSystem blkio) {

        this.blkio = blkio;

    }

    private SubSystem MemorySubSystem() {

        return memory;

    }

    private SubSystem CpuSubSystem() {

        return cpu;

    }

    private SubSystem CpuAcctSubSystem() {

        return cpuacct;

    }

    private SubSystem CpuSetSubSystem() {

        return cpuset;

    }

    private SubSystem BlkIOSubSystem() {

        return blkio;

    }

    public String getProvider() {

        return PROVIDER_NAME;

    }

    /*****************************************************************

     * CPU Accounting Subsystem

     ****************************************************************/

    public long getCpuUsage() {

        return SubSystem.getLongValue(cpuacct, "cpuacct.usage");

    }

    public long[] getPerCpuUsage() {

        String usagelist = SubSystem.getStringValue(cpuacct, "cpuacct.usage_percpu");

        if (usagelist == null) {

            return new long[0];

        }

        String list[] = usagelist.split(" ");

        long percpu[] = new long[list.length];

        for (int i = 0; i < list.length; i++) {

            percpu[i] = Long.parseLong(list[i]);

        }

        return percpu;

    }

    public long getCpuUserUsage() {

        return SubSystem.getLongEntry(cpuacct, "cpuacct.stat", "user");

    }

    public long getCpuSystemUsage() {

        return SubSystem.getLongEntry(cpuacct, "cpuacct.stat", "system");

    }

    /*****************************************************************

     * CPU Subsystem

     ****************************************************************/

    public long getCpuPeriod() {

        return SubSystem.getLongValue(cpuacct, "cpu.cfs_period_us");

    }

    public long getCpuQuota() {

        return SubSystem.getLongValue(cpuacct, "cpu.cfs_quota_us");

    }

    public long getCpuShares() {

        long retval = SubSystem.getLongValue(cpuacct, "cpu.shares");

        if (retval == 0 || retval == 1024)

            return -1;

        else

            return retval;

    }

    public long getCpuNumPeriods() {

        return SubSystem.getLongEntry(cpuacct, "cpu.stat", "nr_periods");

    }

    public long getCpuNumThrottled() {

        return SubSystem.getLongEntry(cpuacct, "cpu.stat", "nr_throttled");

    }

    public long getCpuThrottledTime() {

        return SubSystem.getLongEntry(cpuacct, "cpu.stat", "throttled_time");

    }

    public long getEffectiveCpuCount() {

        return Runtime.getRuntime().availableProcessors();

    }

    /*****************************************************************

     * CPUSet Subsystem

     ****************************************************************/

    public int[] getCpuSetCpus() {

        return SubSystem.StringRangeToIntArray(SubSystem.getStringValue(cpuset, "cpuset.cpus"));

    }

    public int[] getEffectiveCpuSetCpus() {

        return SubSystem.StringRangeToIntArray(SubSystem.getStringValue(cpuset, "cpuset.effective_cpus"));

    }

    public int[] getCpuSetMems() {

        return SubSystem.StringRangeToIntArray(SubSystem.getStringValue(cpuset, "cpuset.mems"));

    }

    public int[] getEffectiveCpuSetMems() {

        return SubSystem.StringRangeToIntArray(SubSystem.getStringValue(cpuset, "cpuset.effective_mems"));

    }

    public double getCpuSetMemoryPressure() {

        return SubSystem.getDoubleValue(cpuset, "cpuset.memory_pressure");

    }

    public boolean isCpuSetMemoryPressureEnabled() {

        long val = SubSystem.getLongValue(cpuset, "cpuset.memory_pressure_enabled");

        return (val == 1);

    }

    /*****************************************************************

     * Memory Subsystem

     ****************************************************************/

    public long getMemoryFailCount() {

        return SubSystem.getLongValue(memory, "memory.failcnt");

    }

    public long getMemoryLimit() {

        long retval = SubSystem.getLongValue(memory, "memory.limit_in_bytes");

        return retval > unlimited_minimum ? -1L : retval;

    }

    public long getMemoryMaxUsage() {

        return SubSystem.getLongValue(memory, "memory.max_usage_in_bytes");

    }

    public long getMemoryUsage() {

        return SubSystem.getLongValue(memory, "memory.usage_in_bytes");

    }

    public long getKernelMemoryFailCount() {

        return SubSystem.getLongValue(memory, "memory.kmem.failcnt");

    }

    public long getKernelMemoryLimit() {

        long retval = SubSystem.getLongValue(memory, "memory.kmem.limit_in_bytes");

        return retval > unlimited_minimum ? -1L : retval;

    }

    public long getKernelMemoryMaxUsage() {

        return SubSystem.getLongValue(memory, "memory.kmem.max_usage_in_bytes");

    }

    public long getKernelMemoryUsage() {

        return SubSystem.getLongValue(memory, "memory.kmem.usage_in_bytes");

    }

    public long getTcpMemoryFailCount() {

        return SubSystem.getLongValue(memory, "memory.kmem.tcp.failcnt");

    }

    public long getTcpMemoryLimit() {

        long retval =  SubSystem.getLongValue(memory, "memory.kmem.tcp.limit_in_bytes");

        return retval > unlimited_minimum ? -1L : retval;

    }

    public long getTcpMemoryMaxUsage() {

        return SubSystem.getLongValue(memory, "memory.kmem.tcp.max_usage_in_bytes");

    }

    public long getTcpMemoryUsage() {

        return SubSystem.getLongValue(memory, "memory.kmem.tcp.usage_in_bytes");

    }

    public long getMemoryAndSwapFailCount() {

        return SubSystem.getLongValue(memory, "memory.memsw.failcnt");

    }

    public long getMemoryAndSwapLimit() {

        long retval = SubSystem.getLongValue(memory, "memory.memsw.limit_in_bytes");

        return retval > unlimited_minimum ? -1L : retval;

    }

    public long getMemoryAndSwapMaxUsage() {

        return SubSystem.getLongValue(memory, "memory.memsw.max_usage_in_bytes");

    }

    public long getMemoryAndSwapUsage() {

        return SubSystem.getLongValue(memory, "memory.memsw.usage_in_bytes");

    }

    public boolean isMemoryOOMKillEnabled() {

        long val = SubSystem.getLongEntry(memory, "memory.oom_control", "oom_kill_disable");

        return (val == 0);

    }

    public long getMemorySoftLimit() {

        long retval = SubSystem.getLongValue(memory, "memory.soft_limit_in_bytes");

        return retval > unlimited_minimum ? -1L : retval;

    }

    /*****************************************************************

     * BlKIO Subsystem

     ****************************************************************/

    public long getBlkIOServiceCount() {

        return SubSystem.getLongEntry(blkio, "blkio.throttle.io_service_bytes", "Total");

    }

    public long getBlkIOServiced() {

        return SubSystem.getLongEntry(blkio, "blkio.throttle.io_serviced", "Total");

    }

}