Package org.apache.druid.java.util.metrics.cgroups

Class ProcCgroupDiscoverer

java.lang.Object

org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer

All Implemented Interfaces:

CgroupDiscoverer

Direct Known Subclasses:

ProcCgroupV2Discoverer

public class ProcCgroupDiscoverer
extends Object
implements CgroupDiscoverer

Field Summary

Fields

Modifier and Type	Field	Description
protected final File	procDir

Constructor Summary

Constructors

Constructor	Description
ProcCgroupDiscoverer(Path procDir)	Create a proc discovery mechanism based on a `/proc` directory.

Method Summary

Modifier and Type	Method	Description
Path	discover(String cgroup)	Gets the path in the virtual FS for the given cgroup (cpu, mem, etc.).
protected org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer.ProcMountsEntry	getMountEntry(File procMounts, String cgroup)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

procDir

protected final File procDir

Constructor Details

ProcCgroupDiscoverer

public ProcCgroupDiscoverer(Path procDir)

Create a proc discovery mechanism based on a `/proc` directory.

Parameters:

procDir - The directory under proc. This is usually `/proc/self` or `/proc/#pid`

Method Details

discover

public Path discover(String cgroup)

Gets the path in the virtual FS for the given cgroup (cpu, mem, etc.). The method first retrieves 2 paths: - The cgroup virtual FS mount point by calling /proc/mounts. This is usually like '/sys/fs/cgroup/cpu'. - The heirarchy path by calling /proc/[pid]/cgroup. In Docker this can look like '/docker/4b053f1267369a19dcdcb293e1b4d6b71fd0f26bf7711d589f19d48af92e6278' The method then tries to find the final virtual FS path by contenating the 2 paths first, and then falling back to the root virtual FS path. In this example, the method tries '/sys/fs/cgroup/cpu/docker/4b053f1267369a19dcdcb293e1b4d6b71fd0f26bf7711d589f19d48af92e6278' and then falls back to '/sys/fs/cgroup/cpu'. An exception is thrown if neither path exists.

Specified by:

discover in interface CgroupDiscoverer

Parameters:

cgroup - The cgroup.

Returns:

the virtual FS path.

getMountEntry

protected org.apache.druid.java.util.metrics.cgroups.ProcCgroupDiscoverer.ProcMountsEntry getMountEntry(File procMounts,
 String cgroup)