Small utility class used to get the stats of a container. More...

#include <DobbyStats.h>

Classes
struct	Process

Public Member Functions
	DobbyStats (const ContainerId &id, const std::shared_ptr< IDobbyEnv > &env, const std::shared_ptr< IDobbyUtils > &utils)

const Json::Value &	stats () const

Private Types
typedef struct DobbyStats::Process	Process

Static Private Member Functions
static ssize_t	readCgroupFile (const ContainerId &id, const std::string &cgroupMntPath, const std::string &cgroupfileName, char *buf, size_t bufLen)
	Reads a maximum of 4096 bytes from the given cgroup file.

static Json::Value	readSingleCgroupValue (const ContainerId &id, const std::string &cgroupMntPath, const std::string &cgroupfileName)
	Reads a single value from the given cgroup file.

static std::vector< int64_t >	readMultipleCgroupValues (const ContainerId &id, const std::string &cgroupMntPath, const std::string &cgroupfileName)
	Reads multiple values from the given cgroup file.

static Json::Value	readMultipleCgroupValuesJson (const ContainerId &id, const std::string &cgroupMntPath, const std::string &cgroupfileName)

static Json::Value	getStats (const ContainerId &id, const std::shared_ptr< IDobbyEnv > &env, const std::shared_ptr< IDobbyUtils > &utils)
	Gets the stats for the container.

static Json::Value	getProcessTree (const ContainerId &id, const std::string &cpuCgroupMntPath, const std::shared_ptr< IDobbyUtils > &utils)
	Builds a json array of the processes running in the container.

static Process	getProcessInfo (pid_t pid, const std::shared_ptr< IDobbyUtils > &utils)
	Returns information about a given PID.

static pid_t	readNsPidFromProc (pid_t pid)
	Given a pid (in global namespace) tries to find what it's namespace pid is.

Private Attributes
const Json::Value	mStats

Detailed Description

Small utility class used to get the stats of a container.

There is not much to this class, it's just a collection of utility functions for gathering statistics on a container with a given id.

Note that the code in this class tends not to print errors if it can't gather some stats, that's by design as it's meant to be a best effort.

Member Function Documentation

◆ getProcessInfo()

DobbyStats::Process DobbyStats::getProcessInfo	(	pid_t	pid,
		const std::shared_ptr< IDobbyUtils > &	utils
	)

staticprivate

Returns information about a given PID.

Parameters

[in] pid The PID to get information about

Returns: Process struct containing information about the specified process

◆ getProcessTree()

Json::Value DobbyStats::getProcessTree	(	const ContainerId &	id,
		const std::string &	cpuCgroupMntPath,
		const std::shared_ptr< IDobbyUtils > &	utils
	)

staticprivate

Builds a json array of the processes running in the container.

Will return a json array with all the processes inside the container with their filename, cmdline and PID (both in the host and container namespace)

"processes": [ { "pid": "2345", "nsPid": "1" "file": "/usr/libexec/DobbyInit", "cmdline": "/usr/libexec/DobbyInit sleep 30", } ]

Parameters

[in] id The string id of the container.

Returns: Json array with all container processes

◆ getStats()

Json::Value DobbyStats::getStats	(	const ContainerId &	id,
		const std::shared_ptr< IDobbyEnv > &	env,
		const std::shared_ptr< IDobbyUtils > &	utils
	)

staticprivate

Gets the stats for the container.

This is primarily a debugging method, used to get statistics on the container and roughly correlates to the 'runc events –stats <id>' call.

The reply is a json formatted string containing some info, it's form may change over time.

{
    "timestamp": 348134887768,
    "pids": [ 2046, 2064 ],
    "cpu": {
        "usage": {
            "total":734236982,
            "percpu":[348134887,386102095]
        }
    },
    "memory":{
        "user": {
            "limit":41943040,
            "usage":356352,
            "max":524288,
            "failcnt":0
        }
    }
    "gpu":{
        "memory": {
            "limit":41943040,
            "usage":356352,
            "max":524288,
            "failcnt":0
        }
    }
    ...
}

Parameters

[in]	id	The container id, assumed to also be the name of the cgroups.
[in]	env	The environment setup, used to get the mount point(s) of the various cgroups.

Returns: The populated json stats, may be an empty object if no cgroups could be found.

◆ readCgroupFile()

ssize_t DobbyStats::readCgroupFile	(	const ContainerId &	id,
		const std::string &	cgroupMntPath,
		const std::string &	cgroupfileName,
		char *	buf,
		size_t	bufLen
	)

staticprivate

Reads a maximum of 4096 bytes from the given cgroup file.

The path to read is made up like: <cgroupMntPath>/<id>/<cgroupfileName>

Parameters

[in]	id	The string id of the container.
[in]	cgroupMntPath	The path to the cgroup mount point.
[in]	cgroupfileName	The name of the cgroup file.
[out]	buf	Buffer to store the file contents in
[in]	bufLen	The size of the buffer.

Returns: The number of characters copied, or

◆ readMultipleCgroupValues()

std::vector< int64_t > DobbyStats::readMultipleCgroupValues	(	const ContainerId &	id,
		const std::string &	cgroupMntPath,
		const std::string &	cgroupfileName
	)

staticprivate

Reads multiple values from the given cgroup file.

The path to read is made up like:

<cgroupMntPath>/<id>/<cgroupfileName>

Each value is expected to be delimited with either a space, tab or newline.

Parameters

[in]	id	The string id of the container.
[in]	cgroupMntPath	The path to the cgroup mount point.
[in]	cgroupfileName	The name of the cgroup file.

Returns: The value read as a json object, typically an integer value.

◆ readNsPidFromProc()

pid_t DobbyStats::readNsPidFromProc ( pid_t pid )

staticprivate

Given a pid (in global namespace) tries to find what it's namespace pid is.

This reads the /proc/<pid>/status file, line NStgid.

Parameters

[in] pid The real pid of the process to lookup.

Returns: Set of all the real pids within the container.

◆ readSingleCgroupValue()

Json::Value DobbyStats::readSingleCgroupValue	(	const ContainerId &	id,
		const std::string &	cgroupMntPath,
		const std::string &	cgroupfileName
	)

staticprivate

Reads a single value from the given cgroup file.

The path to read is made up like:

<cgroupMntPath>/<id>/<cgroupfileName>

Parameters

[in]	id	The string id of the container.
[in]	cgroupMntPath	The path to the cgroup mount point.
[in]	cgroupfileName	The name of the cgroup file.

Returns: The value read as a json object, typically an integer value.

The documentation for this class was generated from the following files:

daemon/lib/source/include/DobbyStats.h
daemon/lib/source/DobbyStats.cpp

Classes

Public Member Functions

Private Types

Static Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

◆ getProcessInfo()

◆ getProcessTree()

◆ getStats()

◆ readCgroupFile()

◆ readMultipleCgroupValues()

◆ readNsPidFromProc()

◆ readSingleCgroupValue()