ghw

ghw - Go HardWare discovery/inspection library

ghw is a Go library providing hardware inspection and discovery for Linux and Windows. There currently exists partial support for MacOSX.

Design Principles

• No root privileges needed for discovery

  ghw goes the extra mile to be useful without root privileges. We query for host hardware information as directly as possible without relying on shellouts to programs like dmidecode that require root privileges to execute.

  Elevated privileges are indeed required to query for some information, but ghw will never error out if blocked from reading that information. Instead, ghw will print a warning message about the information that could not be retrieved. You may disable these warning messages with the GHW_DISABLE_WARNINGS environment variable.

• Well-documented code and plenty of example code

  The code itself should be well-documented with lots of usage examples.

• Interfaces should be consistent across modules

  Each module in the library should be structured in a consistent fashion, and the structs returned by various library functions should have consistent attribute and method names.

Inspecting != Monitoring

ghw is a tool for gathering information about your hardware's capacity and capabilities.

It is important to point out that ghw does NOT report information that is temporary or variable. It is NOT a system monitor nor is it an appropriate tool for gathering data points for metrics that change over time. If you are looking for a system that tracks usage of CPU, memory, network I/O or disk I/O, there are plenty of great open source tools that do this! Check out the Prometheus project for a great example.

Usage

ghw has functions that return an Info object about a particular hardware domain (e.g. CPU, Memory, Block storage, etc).

Use the following functions in ghw to inspect information about the host hardware:

• ghw.CPU()
• ghw.Memory()
• ghw.Block() (block storage)
• ghw.Topology() (processor architecture, NUMA topology and memory cache hierarchy)
• ghw.Network()
• ghw.PCI()
• ghw.GPU() (graphical processing unit)
• ghw.Accelerator() (processing accelerators, AI)
• ghw.Chassis()
• ghw.BIOS()
• ghw.Baseboard()
• ghw.Product()

CPU

The ghw.CPU() function returns a ghw.CPUInfo struct that contains information about the CPUs on the host system.

ghw.CPUInfo contains the following fields:

• ghw.CPUInfo.TotalCores has the total number of physical cores the host system contains
• ghw.CPUInfo.TotalHardwareThreads has the total number of hardware threads the host system contains
• ghw.CPUInfo.Processors is an array of ghw.Processor structs, one for each physical processor package contained in the host

Each ghw.Processor struct contains a number of fields:

• ghw.Processor.ID is the physical processor uint32 ID according to the system
• ghw.Processor.TotalCores is the number of physical cores in the processor package
• ghw.Processor.TotalHardwareThreads is the number of hardware threads in the processor package
• ghw.Processor.Vendor is a string containing the vendor name
• ghw.Processor.Model is a string containing the vendor's model name
• ghw.Processor.Capabilities (Linux only) is an array of strings indicating the features the processor has enabled
• ghw.Processor.Cores (Linux only) is an array of ghw.ProcessorCore structs that are packed onto this physical processor

A ghw.ProcessorCore has the following fields:

• ghw.ProcessorCore.ID is the uint32 identifier that the host gave this core. Note that this does not necessarily equate to a zero-based index of the core within a physical package. For example, the core IDs for an Intel Core i7 are 0, 1, 2, 8, 9, and 10
• ghw.ProcessorCore.TotalHardwareThreads is the number of hardware threads associated with the core
• ghw.ProcessorCore.LogicalProcessors is an array of ints representing the logical processor IDs assigned to any processing unit for the core. These are sometimes called the "thread siblings". Logical processor IDs are the zero-based index of the processor on the host and are not related to the core ID.

package main

import (
	"fmt"
	"math"
	"strings"

	"github.com/jaypipes/ghw"
)

func main() {
	cpu, err := ghw.CPU()
	if err != nil {
		fmt.Printf("Error getting CPU info: %v", err)
	}

	fmt.Printf("%v\n", cpu)

	for _, proc := range cpu.Processors {
		fmt.Printf(" %v\n", proc)
		for _, core := range proc.Cores {
			fmt.Printf("  %v\n", core)
		}
		if len(proc.Capabilities) > 0 {
			// pretty-print the (large) block of capability strings into rows
			// of 6 capability strings
			rows := int(math.Ceil(float64(len(proc.Capabilities)) / float64(6)))
			for row := 1; row < rows; row = row + 1 {
				rowStart := (row * 6) - 1
				rowEnd := int(math.Min(float64(rowStart+6), float64(len(proc.Capabilities))))
				rowElems := proc.Capabilities[rowStart:rowEnd]
				capStr := strings.Join(rowElems, " ")
				if row == 1 {
					fmt.Printf("  capabilities: [%s\n", capStr)
				} else if rowEnd < len(proc.Capabilities) {
					fmt.Printf("                 %s\n", capStr)
				} else {
					fmt.Printf("                 %s]\n", capStr)
				}
			}
		}
	}
}

Example output from my personal workstation:

cpu (1 physical package, 6 cores, 12 hardware threads)
 physical package #0 (6 cores, 12 hardware threads)
  processor core #0 (2 threads), logical processors [0 6]
  processor core #1 (2 threads), logical processors [1 7]
  processor core #2 (2 threads), logical processors [2 8]
  processor core #3 (2 threads), logical processors [3 9]
  processor core #4 (2 threads), logical processors [4 10]
  processor core #5 (2 threads), logical processors [5 11]
  capabilities: [msr pae mce cx8 apic sep
                 mtrr pge mca cmov pat pse36
                 clflush dts acpi mmx fxsr sse
                 sse2 ss ht tm pbe syscall
                 nx pdpe1gb rdtscp lm constant_tsc arch_perfmon
                 pebs bts rep_good nopl xtopology nonstop_tsc
                 cpuid aperfmperf pni pclmulqdq dtes64 monitor
                 ds_cpl vmx est tm2 ssse3 cx16
                 xtpr pdcm pcid sse4_1 sse4_2 popcnt
                 aes lahf_lm pti retpoline tpr_shadow vnmi
                 flexpriority ept vpid dtherm ida arat]

Memory

The ghw.Memory() function returns a ghw.MemoryInfo struct that contains information about the RAM on the host system.

ghw.MemoryInfo contains the following fields:

• ghw.MemoryInfo.TotalPhysicalBytes contains the amount of physical memory on the host
• ghw.MemoryInfo.TotalUsableBytes contains the amount of memory the system can actually use. Usable memory accounts for things like the kernel's resident memory size and some reserved system bits. Please note this value is NOT the amount of memory currently in use by processes in the system. See [the discussion][#physical-versus-usage-memory] about the difference.
• ghw.MemoryInfo.SupportedPageSizes is an array of integers representing the size, in bytes, of memory pages the system supports
• ghw.MemoryInfo.Modules is an array of pointers to ghw.MemoryModule structs, one for each physical DIMM. Currently, this information is only included on Windows, with Linux support planned.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	memory, err := ghw.Memory()
	if err != nil {
		fmt.Printf("Error getting memory info: %v", err)
	}

	fmt.Println(memory.String())
}

Example output from my personal workstation:

memory (24GB physical, 24GB usable)

Physical versus Usable Memory

There has been some confusion regarding the difference between the total physical bytes versus total usable bytes of memory.

Some of this confusion has been due to a misunderstanding of the term "usable". As mentioned above, ghw does inspection of the system's capacity.

A host computer has two capacities when it comes to RAM. The first capacity is the amount of RAM that is contained in all memory banks (DIMMs) that are attached to the motherboard. ghw.MemoryInfo.TotalPhysicalBytes refers to this first capacity.

There is a (usually small) amount of RAM that is consumed by the bootloader before the operating system is started (booted). Once the bootloader has booted the operating system, the amount of RAM that may be used by the operating system and its applications is fixed. ghw.MemoryInfo.TotalUsableBytes refers to this second capacity.

You can determine the amount of RAM that the bootloader used (that is not made available to the operating system) by subtracting ghw.MemoryInfo.TotalUsableBytes from ghw.MemoryInfo.TotalPhysicalBytes:

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	memory, err := ghw.Memory()
	if err != nil {
		fmt.Printf("Error getting memory info: %v", err)
	}

        phys := memory.TotalPhysicalBytes
        usable := memory.TotalUsableBytes

	fmt.Printf("The bootloader consumes %d bytes of RAM\n", phys - usable)
}

Example output from my personal workstation booted into a Windows10 operating system with a Linux GRUB bootloader:

The bootloader consumes 3832720 bytes of RAM

Block storage

The ghw.Block() function returns a ghw.BlockInfo struct that contains information about the block storage on the host system.

ghw.BlockInfo contains the following fields:

• ghw.BlockInfo.TotalSizeBytes contains the amount of physical block storage on the host.
• ghw.BlockInfo.Disks is an array of pointers to ghw.Disk structs, one for each disk found by the system

Each ghw.Disk struct contains the following fields:

• ghw.Disk.Name contains a string with the short name of the disk, e.g. "sda"
• ghw.Disk.SizeBytes contains the amount of storage the disk provides
• ghw.Disk.PhysicalBlockSizeBytes contains the size of the physical blocks used on the disk, in bytes. This is typically the minimum amount of data that will be written in a single write operation for the disk.
• ghw.Disk.IsRemovable contains a boolean indicating if the disk drive is removable
• ghw.Disk.DriveType is the type of drive. It is of type ghw.DriveType which has a ghw.DriveType.String() method that can be called to return a string representation of the bus. This string will be HDD, FDD, ODD, or SSD, which correspond to a hard disk drive (rotational), floppy drive, optical (CD/DVD) drive and solid-state drive.
• ghw.Disk.StorageController is the type of storage controller. It is of type ghw.StorageController which has a ghw.StorageController.String() method that can be called to return a string representation of the bus. This string will be SCSI, IDE, virtio, MMC, or NVMe
• ghw.Disk.BusPath (Linux, Darwin only) is the filepath to the bus used by the disk.
• ghw.Disk.NUMANodeID (Linux only) is the numeric index of the NUMA node this disk is local to, or -1 if the host system is not a NUMA system or is not Linux.
• ghw.Disk.Vendor contains a string with the name of the hardware vendor for the disk
• ghw.Disk.Model contains a string with the vendor-assigned disk model name
• ghw.Disk.SerialNumber contains a string with the disk's serial number
• ghw.Disk.WWN contains a string with the disk's World Wide Name
• ghw.Disk.Partitions contains an array of pointers to ghw.Partition structs, one for each partition on the disk

Each ghw.Partition struct contains these fields:

• ghw.Partition.Name contains a string with the short name of the partition, e.g. sda1
• ghw.Partition.Label contains the label for the partition itself. On Linux systems, this is derived from the ID_PART_ENTRY_NAME udev entry for the partition.
• ghw.Partition.FilesystemLabel contains the label for the filesystem housed on the partition. On Linux systems, this is derived from the ID_FS_NAME udev entry for the partition.
• ghw.Partition.SizeBytes contains the amount of storage the partition provides
• ghw.Partition.MountPoint contains a string with the partition's mount point, or "" if no mount point was discovered
• ghw.Partition.Type contains a string indicated the filesystem type for the partition, or "" if the system could not determine the type
• ghw.Partition.IsReadOnly is a bool indicating the partition is read-only
• ghw.Partition.Disk is a pointer to the ghw.Disk object associated with the partition.
• ghw.Partition.UUID is a string containing the partition UUID on Linux and MacOS, and the VolumeSerialNumber on Windows (e.g. "A8C3D032"). On Linux systems, this is derived from the ID_PART_ENTRY_UUID udev entry for the partition.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	block, err := ghw.Block()
	if err != nil {
		fmt.Printf("Error getting block storage info: %v", err)
	}

	fmt.Printf("%v\n", block)

	for _, disk := range block.Disks {
		fmt.Printf(" %v\n", disk)
		for _, part := range disk.Partitions {
			fmt.Printf("  %v\n", part)
		}
	}
}

Example output from my personal workstation:

block storage (1 disk, 2TB physical storage)
 sda HDD (2TB) SCSI [@pci-0000:04:00.0-scsi-0:1:0:0 (node #0)] vendor=LSI model=Logical_Volume serial=600508e000000000f8253aac9a1abd0c WWN=0x600508e000000000f8253aac9a1abd0c
  /dev/sda1 (100MB)
  /dev/sda2 (187GB)
  /dev/sda3 (449MB)
  /dev/sda4 (1KB)
  /dev/sda5 (15GB)
  /dev/sda6 (2TB) [ext4] mounted@/

NOTE: ghw looks in the udev runtime database for some information. If you are using ghw in a container, remember to bind mount /dev/disk and /run into your container, otherwise ghw won't be able to query the udev DB or sysfs paths for information.

Topology

NOTE: Topology support is currently Linux-only. Windows support is planned.

The ghw.Topology() function returns a ghw.TopologyInfo struct that contains information about the host computer's architecture (NUMA vs. SMP), the host's NUMA node layout and processor-specific memory caches.

The ghw.TopologyInfo struct contains two fields:

• ghw.TopologyInfo.Architecture contains an enum with the value ghw.NUMA or ghw.SMP depending on what the topology of the system is
• ghw.TopologyInfo.Nodes is an array of pointers to ghw.TopologyNode structs, one for each topology node (typically physical processor package) found by the system

Each ghw.TopologyNode struct contains the following fields:

• ghw.TopologyNode.ID is the system's uint32 identifier for the node
• ghw.TopologyNode.Memory is a ghw.MemoryArea struct describing the memory attached to this node.
• ghw.TopologyNode.Cores is an array of pointers to ghw.ProcessorCore structs that are contained in this node
• ghw.TopologyNode.Caches is an array of pointers to ghw.MemoryCache structs that represent the low-level caches associated with processors and cores on the system
• ghw.TopologyNode.Distance is an array of distances between NUMA nodes as reported by the system.

ghw.MemoryArea describes a collection of physical RAM on the host.

In the simplest and most common case, all system memory fits in a single memory area. In more complex host systems, like NUMA systems, many memory areas may be present in the host system (e.g. one for each NUMA cell).

The ghw.MemoryArea struct contains the following fields:

• ghw.MemoryArea.TotalPhysicalBytes contains the amount of physical memory associated with this memory area.
• ghw.MemoryArea.TotalUsableBytes contains the amount of memory of this memory area the system can actually use. Usable memory accounts for things like the kernel's resident memory size and some reserved system bits. Please note this value is NOT the amount of memory currently in use by processes in the system. See [the discussion][#physical-versus-usage-memory] about the difference.

See above in the CPU section for information about the ghw.ProcessorCore struct and how to use and query it.

Each ghw.MemoryCache struct contains the following fields:

• ghw.MemoryCache.Type is an enum that contains one of ghw.DATA, ghw.INSTRUCTION or ghw.UNIFIED depending on whether the cache stores CPU instructions, program data, or both
• ghw.MemoryCache.Level is a positive integer indicating how close the cache is to the processor. The lower the number, the closer the cache is to the processor and the faster the processor can access its contents
• ghw.MemoryCache.SizeBytes is an integer containing the number of bytes the cache can contain
• ghw.MemoryCache.LogicalProcessors is an array of integers representing the logical processors that use the cache

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	topology, err := ghw.Topology()
	if err != nil {
		fmt.Printf("Error getting topology info: %v", err)
	}

	fmt.Printf("%v\n", topology)

	for _, node := range topology.Nodes {
		fmt.Printf(" %v\n", node)
		for _, cache := range node.Caches {
			fmt.Printf("  %v\n", cache)
		}
	}
}

Example output from my personal workstation:

topology SMP (1 nodes)
 node #0 (6 cores)
  L1i cache (32 KB) shared with logical processors: 3,9
  L1i cache (32 KB) shared with logical processors: 2,8
  L1i cache (32 KB) shared with logical processors: 11,5
  L1i cache (32 KB) shared with logical processors: 10,4
  L1i cache (32 KB) shared with logical processors: 0,6
  L1i cache (32 KB) shared with logical processors: 1,7
  L1d cache (32 KB) shared with logical processors: 11,5
  L1d cache (32 KB) shared with logical processors: 10,4
  L1d cache (32 KB) shared with logical processors: 3,9
  L1d cache (32 KB) shared with logical processors: 1,7
  L1d cache (32 KB) shared with logical processors: 0,6
  L1d cache (32 KB) shared with logical processors: 2,8
  L2 cache (256 KB) shared with logical processors: 2,8
  L2 cache (256 KB) shared with logical processors: 3,9
  L2 cache (256 KB) shared with logical processors: 0,6
  L2 cache (256 KB) shared with logical processors: 10,4
  L2 cache (256 KB) shared with logical processors: 1,7
  L2 cache (256 KB) shared with logical processors: 11,5
  L3 cache (12288 KB) shared with logical processors: 0,1,10,11,2,3,4,5,6,7,8,9

Network

The ghw.Network() function returns a ghw.NetworkInfo struct that contains information about the host computer's networking hardware.

The ghw.NetworkInfo struct contains one field:

• ghw.NetworkInfo.NICs is an array of pointers to ghw.NIC structs, one for each network interface controller found for the system

Each ghw.NIC struct contains the following fields:

• ghw.NIC.Name is the system's identifier for the NIC
• ghw.NIC.MACAddress is the Media Access Control (MAC) address for the NIC, if any
• ghw.NIC.IsVirtual is a boolean indicating if the NIC is a virtualized device
• ghw.NIC.Capabilities (Linux only) is an array of pointers to ghw.NICCapability structs that can describe the things the NIC supports. These capabilities match the returned values from the ethtool -k <DEVICE> call on Linux as well as the AutoNegotiation and PauseFrameUse capabilities from ethtool.
• ghw.NIC.PCIAddress (Linux only) is the PCI device address of the device backing the NIC. this is not-nil only if the backing device is indeed a PCI device; more backing devices (e.g. USB) will be added in future versions.
• ghw.NIC.Speed (Linux only) is a string showing the current link speed. On Linux, this field will be present even if ethtool is not available.
• ghw.NIC.Duplex (Linux only) is a string showing the current link duplex. On Linux, this field will be present even if ethtool is not available.
• ghw.NIC.SupportedLinkModes (Linux only) is a string slice containing a list of supported link modes, e.g. "10baseT/Half", "1000baseT/Full".
• ghw.NIC.SupportedPorts (Linux only) is a string slice containing the list of supported port types, e.g. "MII", "TP", "FIBRE", "Twisted Pair".
• ghw.NIC.SupportedFECModes (Linux only) is a string slice containing a list of supported Forward Error Correction (FEC) Modes.
• ghw.NIC.AdvertisedLinkModes (Linux only) is a string slice containing the link modes being advertised during auto negotiation.
• ghw.NIC.AdvertisedFECModes (Linux only) is a string slice containing the Forward Error Correction (FEC) modes advertised during auto negotiation.

The ghw.NICCapability struct contains the following fields:

• ghw.NICCapability.Name is the string name of the capability (e.g. "tcp-segmentation-offload")
• ghw.NICCapability.IsEnabled is a boolean indicating whether the capability is currently enabled/active on the NIC
• ghw.NICCapability.CanEnable is a boolean indicating whether the capability may be enabled

package main

import (
    "fmt"

    "github.com/jaypipes/ghw"
)

func main() {
    net, err := ghw.Network()
    if err != nil {
        fmt.Printf("Error getting network info: %v", err)
    }

    fmt.Printf("%v\n", net)

    for _, nic := range net.NICs {
        fmt.Printf(" %v\n", nic)

        enabledCaps := make([]int, 0)
        for x, cap := range nic.Capabilities {
            if cap.IsEnabled {
                enabledCaps = append(enabledCaps, x)
            }
        }
        if len(enabledCaps) > 0 {
            fmt.Printf("  enabled capabilities:\n")
            for _, x := range enabledCaps {
                fmt.Printf("   - %s\n", nic.Capabilities[x].Name)
            }
        }
    }
}

Example output from my personal laptop:

net (3 NICs)
 docker0
  enabled capabilities:
   - tx-checksumming
   - tx-checksum-ip-generic
   - scatter-gather
   - tx-scatter-gather
   - tx-scatter-gather-fraglist
   - tcp-segmentation-offload
   - tx-tcp-segmentation
   - tx-tcp-ecn-segmentation
   - tx-tcp-mangleid-segmentation
   - tx-tcp6-segmentation
   - udp-fragmentation-offload
   - generic-segmentation-offload
   - generic-receive-offload
   - tx-vlan-offload
   - highdma
   - tx-lockless
   - netns-local
   - tx-gso-robust
   - tx-fcoe-segmentation
   - tx-gre-segmentation
   - tx-gre-csum-segmentation
   - tx-ipxip4-segmentation
   - tx-ipxip6-segmentation
   - tx-udp_tnl-segmentation
   - tx-udp_tnl-csum-segmentation
   - tx-gso-partial
   - tx-sctp-segmentation
   - tx-esp-segmentation
   - tx-vlan-stag-hw-insert
 enp58s0f1
  enabled capabilities:
   - rx-checksumming
   - generic-receive-offload
   - rx-vlan-offload
   - tx-vlan-offload
   - highdma
   - auto-negotiation
 wlp59s0
  enabled capabilities:
   - scatter-gather
   - tx-scatter-gather
   - generic-segmentation-offload
   - generic-receive-offload
   - highdma
   - netns-local

PCI

ghw contains a PCI database inspection and querying facility that allows developers to not only gather information about devices on a local PCI bus but also query for information about hardware device classes, vendor and product information.

NOTE: Parsing of the PCI-IDS file database is provided by the separate github.com/jaypipes/pcidb library. You can read that library's README for more information about the various structs that are exposed on the ghw.PCIInfo struct.

The ghw.PCI() function returns a ghw.PCIInfo struct that contains information about the host computer's PCI devices.

The ghw.PCIInfo struct contains one field:

• ghw.PCIInfo.Devices is a slice of pointers to ghw.PCIDevice structs that describe the PCI devices on the host system

NOTE: PCI products are often referred to by their "device ID". We use the term "product ID" in ghw because it more accurately reflects what the identifier is for: a specific product line produced by the vendor.

The ghw.PCIDevice struct has the following fields:

• ghw.PCIDevice.Vendor is a pointer to a pcidb.Vendor struct that describes the device's primary vendor. This will always be non-nil.
• ghw.PCIDevice.Product is a pointer to a pcidb.Product struct that describes the device's primary product. This will always be non-nil.
• ghw.PCIDevice.Subsystem is a pointer to a pcidb.Product struct that describes the device's secondary/sub-product. This will always be non-nil.
• ghw.PCIDevice.Class is a pointer to a pcidb.Class struct that describes the device's class. This will always be non-nil.
• ghw.PCIDevice.Subclass is a pointer to a pcidb.Subclass struct that describes the device's subclass. This will always be non-nil.
• ghw.PCIDevice.ProgrammingInterface is a pointer to a pcidb.ProgrammingInterface struct that describes the device subclass' programming interface. This will always be non-nil.
• ghw.PCIDevice.Driver is a string representing the device driver the system is using to handle this device. Can be empty string if this information is not available. If the information is not available, this does not mean the device is not functioning, but rather that ghw was not able to retrieve driver information.

The ghw.PCIAddress (which is an alias for the ghw.pci.address.Address struct) contains the PCI address fields. It has a ghw.PCIAddress.String() method that returns the canonical Domain:Bus:Device.Function ([D]BDF) representation of this Address.

The ghw.PCIAddress struct has the following fields:

• ghw.PCIAddress.Domain is a string representing the PCI domain component of the address.
• ghw.PCIAddress.Bus is a string representing the PCI bus component of the address.
• ghw.PCIAddress.Device is a string representing the PCI device component of the address.
• ghw.PCIAddress.Function is a string representing the PCI function component of the address.

NOTE: Older versions (pre-v0.9.0) erroneously referred to the Device field as the Slot field. As noted by @pearsonk in #220, this was a misnomer.

The following code snippet shows how to list the PCI devices on the host system and output a simple list of PCI address and vendor/product information:

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	pci, err := ghw.PCI()
	if err != nil {
		fmt.Printf("Error getting PCI info: %v", err)
	}
	fmt.Printf("host PCI devices:\n")
	fmt.Println("====================================================")

	for _, device := range pci.Devices {
		vendor := device.Vendor
		vendorName := vendor.Name
		if len(vendor.Name) > 20 {
			vendorName = string([]byte(vendorName)[0:17]) + "..."
		}
		product := device.Product
		productName := product.Name
		if len(product.Name) > 40 {
			productName = string([]byte(productName)[0:37]) + "..."
		}
		fmt.Printf("%-12s\t%-20s\t%-40s\n", device.Address, vendorName, productName)
	}
}

on my local workstation the output of the above looks like the following:

host PCI devices:
====================================================
0000:00:00.0	Intel Corporation   	5520/5500/X58 I/O Hub to ESI Port
0000:00:01.0	Intel Corporation   	5520/5500/X58 I/O Hub PCI Express Roo...
0000:00:02.0	Intel Corporation   	5520/5500/X58 I/O Hub PCI Express Roo...
0000:00:03.0	Intel Corporation   	5520/5500/X58 I/O Hub PCI Express Roo...
0000:00:07.0	Intel Corporation   	5520/5500/X58 I/O Hub PCI Express Roo...
0000:00:10.0	Intel Corporation   	7500/5520/5500/X58 Physical and Link ...
0000:00:10.1	Intel Corporation   	7500/5520/5500/X58 Routing and Protoc...
0000:00:14.0	Intel Corporation   	7500/5520/5500/X58 I/O Hub System Man...
0000:00:14.1	Intel Corporation   	7500/5520/5500/X58 I/O Hub GPIO and S...
0000:00:14.2	Intel Corporation   	7500/5520/5500/X58 I/O Hub Control St...
0000:00:14.3	Intel Corporation   	7500/5520/5500/X58 I/O Hub Throttle R...
0000:00:19.0	Intel Corporation   	82567LF-2 Gigabit Network Connection
0000:00:1a.0	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1a.1	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1a.2	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1a.7	Intel Corporation   	82801JI (ICH10 Family) USB2 EHCI Cont...
0000:00:1b.0	Intel Corporation   	82801JI (ICH10 Family) HD Audio Contr...
0000:00:1c.0	Intel Corporation   	82801JI (ICH10 Family) PCI Express Ro...
0000:00:1c.1	Intel Corporation   	82801JI (ICH10 Family) PCI Express Po...
0000:00:1c.4	Intel Corporation   	82801JI (ICH10 Family) PCI Express Ro...
0000:00:1d.0	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1d.1	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1d.2	Intel Corporation   	82801JI (ICH10 Family) USB UHCI Contr...
0000:00:1d.7	Intel Corporation   	82801JI (ICH10 Family) USB2 EHCI Cont...
0000:00:1e.0	Intel Corporation   	82801 PCI Bridge
0000:00:1f.0	Intel Corporation   	82801JIR (ICH10R) LPC Interface Contr...
0000:00:1f.2	Intel Corporation   	82801JI (ICH10 Family) SATA AHCI Cont...
0000:00:1f.3	Intel Corporation   	82801JI (ICH10 Family) SMBus Controller
0000:01:00.0	NEC Corporation     	uPD720200 USB 3.0 Host Controller
0000:02:00.0	Marvell Technolog...	88SE9123 PCIe SATA 6.0 Gb/s controller
0000:02:00.1	Marvell Technolog...	88SE912x IDE Controller
0000:03:00.0	NVIDIA Corporation  	GP107 [GeForce GTX 1050 Ti]
0000:03:00.1	NVIDIA Corporation  	UNKNOWN
0000:04:00.0	LSI Logic / Symbi...	SAS2004 PCI-Express Fusion-MPT SAS-2 ...
0000:06:00.0	Qualcomm Atheros    	AR5418 Wireless Network Adapter [AR50...
0000:08:03.0	LSI Corporation     	FW322/323 [TrueFire] 1394a Controller
0000:3f:00.0	Intel Corporation   	UNKNOWN
0000:3f:00.1	Intel Corporation   	Xeon 5600 Series QuickPath Architectu...
0000:3f:02.0	Intel Corporation   	Xeon 5600 Series QPI Link 0
0000:3f:02.1	Intel Corporation   	Xeon 5600 Series QPI Physical 0
0000:3f:02.2	Intel Corporation   	Xeon 5600 Series Mirror Port Link 0
0000:3f:02.3	Intel Corporation   	Xeon 5600 Series Mirror Port Link 1
0000:3f:03.0	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:03.1	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:03.4	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:04.0	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:04.1	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:04.2	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:04.3	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:05.0	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:05.1	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:05.2	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:05.3	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:06.0	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:06.1	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:06.2	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...
0000:3f:06.3	Intel Corporation   	Xeon 5600 Series Integrated Memory Co...

Finding a PCI device by PCI address

In addition to the above information, the ghw.PCIInfo struct has the following method:

• ghw.PCIInfo.GetDevice(address string)

The following code snippet shows how to call the ghw.PCIInfo.GetDevice() method and use its returned ghw.PCIDevice struct pointer:

package main

import (
	"fmt"
	"os"

	"github.com/jaypipes/ghw"
)

func main() {
	pci, err := ghw.PCI()
	if err != nil {
		fmt.Printf("Error getting PCI info: %v", err)
	}

	addr := "0000:00:00.0"
	if len(os.Args) == 2 {
		addr = os.Args[1]
	}
	fmt.Printf("PCI device information for %s\n", addr)
	fmt.Println("====================================================")
	deviceInfo := pci.GetDevice(addr)
	if deviceInfo == nil {
		fmt.Printf("could not retrieve PCI device information for %s\n", addr)
		return
	}

	vendor := deviceInfo.Vendor
	fmt.Printf("Vendor: %s [%s]\n", vendor.Name, vendor.ID)
	product := deviceInfo.Product
	fmt.Printf("Product: %s [%s]\n", product.Name, product.ID)
	subsystem := deviceInfo.Subsystem
	subvendor := pci.Vendors[subsystem.VendorID]
	subvendorName := "UNKNOWN"
	if subvendor != nil {
		subvendorName = subvendor.Name
	}
	fmt.Printf("Subsystem: %s [%s] (Subvendor: %s)\n", subsystem.Name, subsystem.ID, subvendorName)
	class := deviceInfo.Class
	fmt.Printf("Class: %s [%s]\n", class.Name, class.ID)
	subclass := deviceInfo.Subclass
	fmt.Printf("Subclass: %s [%s]\n", subclass.Name, subclass.ID)
	progIface := deviceInfo.ProgrammingInterface
	fmt.Printf("Programming Interface: %s [%s]\n", progIface.Name, progIface.ID)
}

Here's a sample output from my local workstation:

PCI device information for 0000:03:00.0
====================================================
Vendor: NVIDIA Corporation [10de]
Product: GP107 [GeForce GTX 1050 Ti] [1c82]
Subsystem: UNKNOWN [8613] (Subvendor: ASUSTeK Computer Inc.)
Class: Display controller [03]
Subclass: VGA compatible controller [00]
Programming Interface: VGA controller [00]

GPU

The ghw.GPU() function returns a ghw.GPUInfo struct that contains information about the host computer's graphics hardware.

The ghw.GPUInfo struct contains one field:

• ghw.GPUInfo.GraphicCards is an array of pointers to ghw.GraphicsCard structs, one for each graphics card found for the system

Each ghw.GraphicsCard struct contains the following fields:

• ghw.GraphicsCard.Index is the system's numeric zero-based index for the card on the bus
• ghw.GraphicsCard.Address is the PCI address for the graphics card
• ghw.GraphicsCard.DeviceInfo is a pointer to a ghw.PCIDevice struct describing the graphics card. This may be nil if no PCI device information could be determined for the card.
• ghw.GraphicsCard.Node is an pointer to a ghw.TopologyNode struct that the GPU/graphics card is affined to. On non-NUMA systems, this will always be nil.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	gpu, err := ghw.GPU()
	if err != nil {
		fmt.Printf("Error getting GPU info: %v", err)
	}

	fmt.Printf("%v\n", gpu)

	for _, card := range gpu.GraphicsCards {
		fmt.Printf(" %v\n", card)
	}
}

Example output from my personal workstation:

gpu (1 graphics card)
 card #0 @0000:03:00.0 -> class: 'Display controller' vendor: 'NVIDIA Corporation' product: 'GP107 [GeForce GTX 1050 Ti]'

NOTE: You can read more about the fields of the ghw.PCIDevice struct if you'd like to dig deeper into PCI subsystem and programming interface information

NOTE: You can read more about the fields of the ghw.TopologyNode struct if you'd like to dig deeper into the NUMA/topology subsystem

Accelerator

The ghw.Accelerator() function returns a ghw.AcceleratorInfo struct that contains information about the host computer's processing accelerator hardware. In this category we can find used hardware for AI. The hardware detected in this category will be processing accelerators (PCI class 1200), 3D controllers (0302) and Display controllers (0380).

The ghw.AcceleratorInfo struct contains one field:

• ghw.AcceleratorInfo.Devices is an array of pointers to ghw.AcceleratorDevice structs, one for each processing accelerator card found for the system.

Each ghw.AcceleratorDevice struct contains the following fields:

• ghw.AcceleratorDevice.Address is the PCI address for the processing accelerator card.
• ghw.AcceleratorDevice.PCIDevice is a pointer to a ghw.PCIDevice struct. describing the processing accelerator card. This may be nil if no PCI device information could be determined for the card.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	accel, err := ghw.Accelerator()
	if err != nil {
		fmt.Printf("Error getting processing accelerator info: %v", err)
	}

	fmt.Printf("%v\n", accel)

	for _, card := range accel.Devices {
		fmt.Printf(" %v\n", device)
	}
}

Example output from a testing machine:

processing accelerators (1 device)
 device @0000:00:04.0 -> driver: 'fake_pci_driver' class: 'Processing accelerators' vendor: 'Red Hat, Inc.' product: 'QEMU PCI Test Device'

NOTE: You can read more about the fields of the ghw.PCIDevice struct if you'd like to dig deeper into PCI subsystem and programming interface information

Chassis

The ghw.Chassis() function returns a ghw.ChassisInfo struct that contains information about the host computer's hardware chassis.

The ghw.ChassisInfo struct contains multiple fields:

• ghw.ChassisInfo.AssetTag is a string with the chassis asset tag
• ghw.ChassisInfo.SerialNumber is a string with the chassis serial number
• ghw.ChassisInfo.Type is a string with the chassis type code
• ghw.ChassisInfo.TypeDescription is a string with a description of the chassis type
• ghw.ChassisInfo.Vendor is a string with the chassis vendor
• ghw.ChassisInfo.Version is a string with the chassis version

NOTE: These fields are often missing for non-server hardware. Don't be surprised to see empty string or "None" values.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	chassis, err := ghw.Chassis()
	if err != nil {
		fmt.Printf("Error getting chassis info: %v", err)
	}

	fmt.Printf("%v\n", chassis)
}

Example output from my personal workstation:

chassis type=Desktop vendor=System76 version=thelio-r1

NOTE: Some of the values such as serial numbers are shown as unknown because the Linux kernel by default disallows access to those fields if you're not running as root. They will be populated if it runs as root or otherwise you may see warnings like the following:

WARNING: Unable to read chassis_serial: open /sys/class/dmi/id/chassis_serial: permission denied

You can ignore them or use the Disabling warning messages feature to quiet things down.

BIOS

The ghw.BIOS() function returns a ghw.BIOSInfo struct that contains information about the host computer's basis input/output system (BIOS).

The ghw.BIOSInfo struct contains multiple fields:

• ghw.BIOSInfo.Vendor is a string with the BIOS vendor
• ghw.BIOSInfo.Version is a string with the BIOS version
• ghw.BIOSInfo.Date is a string with the date the BIOS was flashed/created

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	bios, err := ghw.BIOS()
	if err != nil {
		fmt.Printf("Error getting BIOS info: %v", err)
	}

	fmt.Printf("%v\n", bios)
}

Example output from my personal workstation:

bios vendor=System76 version=F2 Z5 date=11/14/2018

Baseboard

The ghw.Baseboard() function returns a ghw.BaseboardInfo struct that contains information about the host computer's hardware baseboard.

The ghw.BaseboardInfo struct contains multiple fields:

• ghw.BaseboardInfo.AssetTag is a string with the baseboard asset tag
• ghw.BaseboardInfo.SerialNumber is a string with the baseboard serial number
• ghw.BaseboardInfo.Vendor is a string with the baseboard vendor
• ghw.BaseboardInfo.Product is a string with the baseboard name on Linux and Product on Windows
• ghw.BaseboardInfo.Version is a string with the baseboard version

NOTE: These fields are often missing for non-server hardware. Don't be surprised to see empty string or "None" values.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	baseboard, err := ghw.Baseboard()
	if err != nil {
		fmt.Printf("Error getting baseboard info: %v", err)
	}

	fmt.Printf("%v\n", baseboard)
}

Example output from my personal workstation:

baseboard vendor=System76 version=thelio-r1

NOTE: Some of the values such as serial numbers are shown as unknown because the Linux kernel by default disallows access to those fields if you're not running as root. They will be populated if it runs as root or otherwise you may see warnings like the following:

WARNING: Unable to read board_serial: open /sys/class/dmi/id/board_serial: permission denied

You can ignore them or use the Disabling warning messages feature to quiet things down.

Product

The ghw.Product() function returns a ghw.ProductInfo struct that contains information about the host computer's hardware product line.

The ghw.ProductInfo struct contains multiple fields:

• ghw.ProductInfo.Family is a string describing the product family
• ghw.ProductInfo.Name is a string with the product name
• ghw.ProductInfo.SerialNumber is a string with the product serial number
• ghw.ProductInfo.UUID is a string with the product UUID
• ghw.ProductInfo.SKU is a string with the product stock unit identifier (SKU)
• ghw.ProductInfo.Vendor is a string with the product vendor
• ghw.ProductInfo.Version is a string with the product version

NOTE: These fields are often missing for non-server hardware. Don't be surprised to see empty string, "Default string" or "None" values.

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	product, err := ghw.Product()
	if err != nil {
		fmt.Printf("Error getting product info: %v", err)
	}

	fmt.Printf("%v\n", product)
}

Example output from my personal workstation:

product family=Default string name=Thelio vendor=System76 sku=Default string version=thelio-r1

NOTE: Some of the values such as serial numbers are shown as unknown because the Linux kernel by default disallows access to those fields if you're not running as root. They will be populated if it runs as root or otherwise you may see warnings like the following:

WARNING: Unable to read product_serial: open /sys/class/dmi/id/product_serial: permission denied

You can ignore them or use the Disabling warning messages feature to quiet things down.

Advanced Usage

Disabling warning messages

When ghw isn't able to retrieve some information, it may print certain warning messages to stderr. To disable these warnings, simply set the GHW_DISABLE_WARNINGS environs variable:

$ ghwc memory
WARNING:
Could not determine total physical bytes of memory. This may
be due to the host being a virtual machine or container with no
/var/log/syslog file, or the current user may not have necessary
privileges to read the syslog. We are falling back to setting the
total physical amount of memory to the total usable amount of memory
memory (24GB physical, 24GB usable)

$ GHW_DISABLE_WARNINGS=1 ghwc memory
memory (24GB physical, 24GB usable)

You can disable warning programmatically using the WithDisableWarnings option:

import (
	"github.com/jaypipes/ghw"
)

mem, err := ghw.Memory(ghw.WithDisableWarnings())

WithDisableWarnings is a alias for the WithNullAlerter option, which in turn leverages the more general Alerter feature of ghw.

You may supply a Alerter to ghw to redirect all the warnings there, like logger objects (see for example golang's stdlib log.Logger). Alerter is in fact the minimal logging interface ghw needs. To learn more, please check the option.Alerterinterface and theghw.WithAlerter()` function.

Overriding the root mountpoint ghw uses

When ghw looks for information about the host system, it considers / as its root mountpoint. So, for example, when looking up CPU information on a Linux system, ghw.CPU() will use the path /proc/cpuinfo.

If you are calling ghw from a system that has an alternate root mountpoint, you can either set the GHW_CHROOT environment variable to that alternate path, or call one of the functions like ghw.CPU() or ghw.Memory() with the ghw.WithChroot() modifier.

For example, if you are executing from within an application container that has bind-mounted the root host filesystem to the mount point /host, you would set GHW_CHROOT to /host so that ghw can find /proc/cpuinfo at /host/proc/cpuinfo.

Alternately, you can use the ghw.WithChroot() function like so:

cpu, err := ghw.CPU(ghw.WithChroot("/host"))

Serialization to JSON or YAML

All of the ghw XXXInfo structs -- e.g. ghw.CPUInfo -- have two methods for producing a serialized JSON or YAML string representation of the contained information:

• JSONString() returns a string containing the information serialized into JSON. It accepts a single boolean parameter indicating whether to use indentation when outputting the string
• YAMLString() returns a string containing the information serialized into YAML

package main

import (
	"fmt"

	"github.com/jaypipes/ghw"
)

func main() {
	mem, err := ghw.Memory()
	if err != nil {
		fmt.Printf("Error getting memory info: %v", err)
	}

	fmt.Printf("%s", mem.YAMLString())
}

the above example code prints the following out on my local workstation:

memory:
  supported_page_sizes:
  - 1073741824
  - 2097152
  total_physical_bytes: 25263415296
  total_usable_bytes: 25263415296

Overriding a specific mountpoint (Linux only)

When running inside containers, it can be cumbersome to only override the root mountpoint. Inside containers, when granting access to the host file systems, it is common to bind-mount them to a non-standard location, like /sys on /host-sys or /proc to /host-proc. It is rarer to mount them to a common subtree (e.g. /sys to /host/sys and /proc to /host/proc...)

To better cover this use case, ghw.WithPathOverrides() can be used to supply a mapping of directories to mountpoints, like this example shows:

cpu, err := ghw.CPU(ghw.WithPathOverrides(ghw.PathOverrides{
	"/proc": "/host-proc",
	"/sys": "/host-sys",
}))

NOTE: This feature works in addition and is composable with the ghw.WithChroot() function and GHW_CHROOT environment variable.

Reading hardware information from a ghw snapshot (Linux only)

The ghw-snapshot tool can create a snapshot of a host's hardware information.

Please read SNAPSHOT.md to learn about creating snapshots with the ghw-snapshot tool.

You can make ghw read hardware information from a snapshot created with ghw-snapshot using environment variables or programmatically.

Use the GHW_SNAPSHOT_PATH environment variable to specify the filepath to a snapshot that ghw will read to determine hardware information. All the needed chroot changes will be automatically performed. By default, the snapshot is unpacked into a temporary directory managed by ghw. This temporary directory is automatically deleted when ghw is finished reading the snapshot.

Three other environment variables are relevant if and only if GHW_SNAPSHOT_PATH is not empty:

• GHW_SNAPSHOT_ROOT let users specify the directory on which the snapshot should be unpacked. This moves the ownership of that directory from ghw to users. For this reason, ghw will not automatically clean up the content unpacked into GHW_SNAPSHOT_ROOT.
• GHW_SNAPSHOT_EXCLUSIVE tells ghw that the directory is meant only to contain the given snapshot, thus ghw will not attempt to unpack it unless the directory is empty. You can use both GHW_SNAPSHOT_ROOT and GHW_SNAPSHOT_EXCLUSIVE to make sure ghw unpacks the snapshot only once regardless of how many ghw packages (e.g. cpu, memory) access it. Set the value of this environment variable to any non-empty string.
• GHW_SNAPSHOT_PRESERVE tells ghw not to clean up the unpacked snapshot. Set the value of this environment variable to any non-empty string.

cpu, err := ghw.CPU(ghw.WithSnapshot(ghw.SnapshotOptions{
	Path: "/path/to/linux-amd64-d4771ed3300339bc75f856be09fc6430.tar.gz",
}))


myRoot := "/my/safe/directory"
cpu, err := ghw.CPU(ghw.WithSnapshot(ghw.SnapshotOptions{
	Path: "/path/to/linux-amd64-d4771ed3300339bc75f856be09fc6430.tar.gz",
	Root: &myRoot,
}))

myOtherRoot := "/my/other/safe/directory"
cpu, err := ghw.CPU(ghw.WithSnapshot(ghw.SnapshotOptions{
	Path:      "/path/to/linux-amd64-d4771ed3300339bc75f856be09fc6430.tar.gz",
	Root:      &myOtherRoot,
	Exclusive: true,
}))

Creating snapshots

You can create ghw snapshots using the ghw-snapshot tool or programmatically using the pkg/snapshot package.

Below is an example of creating a ghw snapshot using the pkg/snapshot package.

import (
	"fmt"
	"os"

	"github.com/jaypipes/ghw/pkg/snapshot"
)

// ...

scratchDir, err := os.MkdirTemp("", "ghw-snapshot-*")
if err != nil {
	fmt.Printf("Error creating clone directory: %v", err)
}
defer os.RemoveAll(scratchDir)

// this step clones all the files and directories ghw cares about
if err := snapshot.CloneTreeInto(scratchDir); err != nil {
	fmt.Printf("error cloning into %q: %v", scratchDir, err)
}

// optionally, you may add extra content into your snapshot.
// ghw will ignore the extra content.
// Glob patterns like `filepath.Glob` are supported.
fileSpecs := []string{
	"/proc/cmdline",
}

// options allows the client code to optionally deference symlinks, or copy
// them into the cloned tree as symlinks
var opts *snapshot.CopyFileOptions
if err := snapshot.CopyFilesInto(fileSpecs, scratchDir, opts); err != nil {
	fmt.Printf("error cloning extra files into %q: %v", scratchDir, err)
}

// automates the creation of the gzipped tarball out of the given tree.
if err := snapshot.PackFrom("my-snapshot.tgz", scratchDir); err != nil {
	fmt.Printf("error packing %q into %q: %v", scratchDir, *output, err)
}

Calling external programs

By default ghw may call external programs, for example ethtool, to learn about hardware capabilities. In some rare circumstances it may be useful to opt out from this behaviour and rely only on the data provided by pseudo-filesystems, like sysfs.

The most common use case is when we want to read a snapshot from ghw. In these cases the information provided by tools will be inconsistent with the data from the snapshot - since they will be run on a different host than the host the snapshot was created for.

To prevent ghw from calling external tools, set the GHW_DISABLE_TOOLS environment variable to any value, or, programmatically, use the ghw.WithDisableTools() function. The default behaviour of ghw is to call external tools when available.

WARNING: on all platforms, disabling external tools make ghw return less data. Unless noted otherwise, there is no fallback flow if external tools are disabled. On MacOSX/Darwin, disabling external tools disables block support entirely

Developers

Contributions to ghw are welcomed! Fork the repo on GitHub and submit a pull request with your proposed changes. Or, feel free to log an issue for a feature request or bug report.