[case15]springboot2增加diskspace指标

序

本文主要研究下如何在springboot2新增一个diskspace指标

disk health indicator

DiskSpaceHealthIndicatorProperties

spring-boot-actuator-autoconfigure-2.0.1.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/system/DiskSpaceHealthIndicatorProperties.java

/**
 * External configuration properties for {@link DiskSpaceHealthIndicator}.
 *
 * @author Andy Wilkinson
 * @since 1.2.0
 */
@ConfigurationProperties(prefix = "management.health.diskspace")
public class DiskSpaceHealthIndicatorProperties {

    private static final int MEGABYTES = 1024 * 1024;

    private static final int DEFAULT_THRESHOLD = 10 * MEGABYTES;

    /**
     * Path used to compute the available disk space.
     */
    private File path = new File(".");

    /**
     * Minimum disk space, in bytes, that should be available.
     */
    private long threshold = DEFAULT_THRESHOLD;

    public File getPath() {
        return this.path;
    }

    public void setPath(File path) {
        Assert.isTrue(path.exists(), () -> "Path '" + path + "' does not exist");
        Assert.isTrue(path.canRead(), () -> "Path '" + path + "' cannot be read");
        this.path = path;
    }

    public long getThreshold() {
        return this.threshold;
    }

    public void setThreshold(long threshold) {
        Assert.isTrue(threshold >= 0, "threshold must be greater than 0");
        this.threshold = threshold;
    }

}

DiskSpaceHealthIndicator

spring-boot-actuator-2.0.1.RELEASE-sources.jar!/org/springframework/boot/actuate/system/DiskSpaceHealthIndicator.java

/**
 * A {@link HealthIndicator} that checks available disk space and reports a status of
 * {@link Status#DOWN} when it drops below a configurable threshold.
 *
 * @author Mattias Severson
 * @author Andy Wilkinson
 * @since 2.0.0
 */
public class DiskSpaceHealthIndicator extends AbstractHealthIndicator {

    private static final Log logger = LogFactory.getLog(DiskSpaceHealthIndicator.class);

    private final File path;

    private final long threshold;

    /**
     * Create a new {@code DiskSpaceHealthIndicator} instance.
     * @param path the Path used to compute the available disk space
     * @param threshold the minimum disk space that should be available (in bytes)
     */
    public DiskSpaceHealthIndicator(File path, long threshold) {
        super("DiskSpace health check failed");
        this.path = path;
        this.threshold = threshold;
    }

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        long diskFreeInBytes = this.path.getUsableSpace();
        if (diskFreeInBytes >= this.threshold) {
            builder.up();
        }
        else {
            logger.warn(String.format(
                    "Free disk space below threshold. "
                            + "Available: %d bytes (threshold: %d bytes)",
                    diskFreeInBytes, this.threshold));
            builder.down();
        }
        builder.withDetail("total", this.path.getTotalSpace())
                .withDetail("free", diskFreeInBytes)
                .withDetail("threshold", this.threshold);
    }

}

metrics

这里我们把disk的health indicator转为metrics

@Component
public class DiskMetrics implements MeterBinder {

    private File rootFilePath;

    public DiskMetrics() {
        this.rootFilePath = new File(".");
    }

    @Override
    public void bindTo(MeterRegistry registry) {
        Gauge.builder("diskspace.total", rootFilePath, c -> c.getTotalSpace())
                .register(registry);
        Gauge.builder("diskspace.free", rootFilePath, c -> c.getFreeSpace())
                .register(registry);
        Gauge.builder("diskspace.usage", rootFilePath, c -> {
            long totalDiskSpace = rootFilePath.getTotalSpace();
            if (totalDiskSpace == 0) {
                return 0.0;
            }

            long usedDiskSpace = totalDiskSpace - rootFilePath.getFreeSpace();
            return Double.valueOf(usedDiskSpace) / totalDiskSpace * 100;
        })
                .register(registry);
    }
}

输出

• /actuator/metrics

{
  "names": [
    "jvm.memory.committed",
    "jvm.buffer.memory.used",
    "jvm.gc.memory.allocated",
    "jvm.memory.used",
    "jvm.gc.max.data.size",
    "logback.events",
    "system.cpu.count",
    "jvm.memory.max",
    "jvm.buffer.total.capacity",
    "jvm.buffer.count",
    "process.files.max",
    "jvm.threads.daemon",
    "process.start.time",
    "diskspace.usage",
    "jvm.gc.live.data.size",
    "process.files.open",
    "process.cpu.usage",
    "process.uptime",
    "system.load.average.1m",
    "statsd.queue.size",
    "statsd.queue.capacity",
    "http.server.requests",
    "system.cpu.usage",
    "diskspace.free",
    "jvm.threads.live",
    "jvm.classes.loaded",
    "jvm.classes.unloaded",
    "jvm.threads.peak",
    "jvm.gc.pause",
    "jvm.gc.memory.promoted",
    "diskspace.total"
  ]
}

• /actuator/metrics/diskspace.usage

{
  "name": "diskspace.usage",
  "measurements": [
    {
      "statistic": "VALUE",
      "value": 96.99886102691765
    }
  ],
  "availableTags": []
}

小结

springboot2默认把diskspace作为一个healthIndicator，其阈值默认为10M。这里通过自定义micrometer的metrics，新增diskspace相关指标，这样就可以统一通过metrcis进行监控报警。

doc

• SpringBoot四大神器之Actuator
• micrometer自定义metrics