pmwebapi

Fetches current values and metadata for all metrics, or only metrics indicated by a comma-separated list of names.

For all numeric metrics with the given NAME prefixes, create an Open Metrics (Prometheus) text export format giving their current value and related metadata.

The response has plain text type rather than JSON commonly used elsewhere in the REST API. This format can be injested by many open source monitoring tools, including Prometheus and pmdaopenmetrics(1).

The native PCP metric metadata (metric name, type, indom, semantics and units) is first output for each metric with # PCP prefix. The metadata reported is of the form described on pmTypeStr(3), pmInDomStr(3), pmSemStr(3) and pmUnitsStr(3) respectively. If the pmUnitsStr(3) units string is empty, then none is output. The units metadata string may contain spaces and extends to the end of the line.

PCP metric names are mapped so that the . separators are exchanged with _ (':' in back-compatibility mode, where "# PCP" is the identifying line suffix). Both metric labels and instances are represented as Prometheus labels, with external instance names being quoted and the flattened PCP metric hierarchy being presented with each value.

$ curl -s http://localhost:44322/metrics?\
	names=proc.nprocs,kernel.pernode.cpu.intr,filesys.blocksize

# PCP5 proc.nprocs 3.8.99 u32 PM_INDOM_NULL instant none
# HELP proc_nprocs instantaneous number of processes
# TYPE proc_nprocs gauge
proc_nprocs {hostname="app1"} 7

# PCP5 kernel.pernode.cpu.intr 60.0.66 u64 60.19 counter millisec
# HELP kernel_pernode_cpu_intr total interrupt CPU [...]
# TYPE kernel_pernode_cpu_intr counter
kernel_pernode_cpu_intr{hostname="app1",instname="node0"} 25603

# PCP5 filesys.blocksize 60.5.9 u32 60.5 instant byte
# HELP filesys_blocksize Size of each block on mounted file[...]
# TYPE filesys_blocksize gauge
filesys_blocksize{hostname="app1",instname="/dev/sda1"} 4096
filesys_blocksize{hostname="app1",instname="/dev/sda2"} 4096

Performs a time series query for either matching identifiers, or matching identifiers with series of time-stamped values.

The query is in the format described in pmseries(1) and is passed to the server via either the expr parameter (HTTP GET) or via the message body (HTTP POST).

When querying for time series matches only, no time window options are specified and matching series identifiers are returned in a JSON array.

$ curl -s http://localhost:44322/series/query?\
	expr=disk.dev.read* | pmjson
[
  "9d8c7fb51ce160eb82e3669aac74ba675dfa8900",
  "ddff1bfe286a3b18cebcbadc1678a68a964fbe9d",
  "605fc77742cd0317597291329561ac4e50c0dd12"
]

When querying for time series values as well, a time window must be specified as part of the query string. The simplest form is to just request the most recent sample.

$ curl -s http://localhost:44322/series/query?\
	expr=disk.dev.read*[samples:1] | pmjson
[
  {
    "series": "9d8c7fb51ce160eb82e3669aac74ba675dfa8900",
    "instance": "c3795d8b757506a2901c6b08b489ba56cae7f0d4",
    "timestamp": 1547483646.2147431,
    "value": "12499"
  }, {
    "series": "ddff1bfe286a3b18cebcbadc1678a68a964fbe9d",
    "instance": "6b08b489ba56cae7f0d4c3795d8b757506a2901c",
    "timestamp": 1547485701.7431218,
    "value": "1118623"
  }, {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "instance": "c3795d8b757506a2901c6b08b489ba56cae7f0d4",
    "timestamp": 1547483646.2147431,
    "value": "71661"
  }
]

Performs values retrievals for one or more time series identifiers. The JSON response contains the same information as the pmseries -q/--query option using any of the time window parameters described on pmseries(1). If no time window parameters are specified, the single most recent value observed is retrieved.

$ curl -s http://localhost:44322/series/values?\
	series=605fc77742cd0317597291329561ac4e50c0dd12 | pmjson
[
  {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "timestamp": 1317633022959.959241041,
    "value": "71660"
  }
]

Performs a descriptor lookup for one or more time series identifiers. The JSON response contains the same information as the pmseries -d/--desc option.

$ curl -s http://localhost:44322/series/descs?\
	series=605fc77742cd0317597291329561ac4e50c0dd12 | pmjson
[
  {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "source": "f5ca7481da8c038325d15612bb1c6473ce1ef16f",
    "pmid": "60.0.4",
    "indom": "60.1",
    "semantics": "counter",
    "type": "u32",
    "units": "count",
  }
]

Performs a label set lookup for one or more time series identifiers. The JSON response contains the same information as the pmseries -l/--labels option.

$ curl -s http://localhost:44322/series/labels?\
	series=605fc77742cd0317597291329561ac4e50c0dd12 | pmjson
[
  {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "labels": {
      "agent": "linux",
      "domainname": "acme.com",
      "groupid": 1000,
      "hostname": "www.acme.com",
      "latitude": -25.28496,
      "longitude": 152.87886,
      "machineid": "295b16e3b6074cc8bdbda8bf96f6930a",
      "platform": "dev",
      "userid": 1000
    }
  }
]

Alternatively, with no series argument, this request will return the list of all known label names.

$ curl -s http://localhost:44322/series/labels | pmjson
[
    "agent",
    "appversion",
    "domainname",
    "groupid",
    "hostname",
    "jobid",
    "latitude",
    "longitude",
    "machineid",
    "platform",
    "userid"
]

Performs a metric name lookup for one or more time series identifiers. The JSON response contains the same information as the pmseries -m/--metrics option.

$ curl -s http://localhost:44322/series/metrics?\
	series=605fc77742cd0317597291329561ac4e50c0dd12 | pmjson
[
  {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "name": "disk.dev.read_bytes"
  }
]

Alternatively, with no series argument, this request will return the list of all known metric names.

$ curl -s http://localhost:44322/series/metrics | pmjson
[
    "disk.dev.read",
    "disk.dev.read_bytes",
    "disk.dev.read_merge",
    "kernel.all.load",
    "kernel.all.pswitch",
    ...
]

Performs a lookup for one or more time series sources, returning an array of all PMAPI context names used to access the time series from that source. The JSON response contains the same information as the pmseries -S/--source option.

$ curl -s http://localhost:44322/series/sources?\
	source=2cd6a38f9339f2dd1f0b4775bda89a9e7244def6 | pmjson
[
  {
    "source": "2cd6a38f9339f2dd1f0b4775bda89a9e7244def6",
    "context": [
      "/var/log/pcp/pmlogger/acme",
      "www.acme.com"
    ]
  }
]

Provide instance identifiers and names for one or more time series identifiers. The JSON response contains the same information as the pmseries -i/--instance option.

$ curl -s http://localhost:44322/series/instances?\
	series=605fc77742cd0317597291329561ac4e50c0dd12 | pmjson
[
  {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "source": "97261ac7742cd4e50c0d03175913295d12605fc7",
    "instance": "c3795d8b757506a2901c6b08b489ba56cae7f0d4"
    "id": 1,
    "name": "sda",
  }, {
    "series": "605fc77742cd0317597291329561ac4e50c0dd12",
    "source": "97261ac7742cd4e50c0d03175913295d12605fc7",
    "instance": "57506a2901c6b08b489ba56cae7f0d4c3795d8b7"
    "id": 2,
    "name": "sdb",
  }
]

Alternatively, with no series argument, this request will return the list of all known instance names.

$ curl -s http://localhost:44322/series/instances | pmjson
[
    "1 minute",
    "5 minute",
    "15 minute",
    "cpu0",
    "cpu1",
    "cpu2",
    "cpu3",
    "node0",
    "node1",
    "sda",
    "sdb",
    ...
]

Load time series performance data from the specified source into the redis-server cache. This request is equivalent to the pmseries -l/--load option.

$ curl -s http://localhost:44322/series/load&\
	expr={source.name:"/var/log/pcp/pmlogger/acme"}
{
  "success": true
}

To create a context for live sampling, a web client can access any /pmapi URL (optionally using the hostspec or context parameter). If no context exists, a new one will be created for that web client, and its identifier returned for future accesses.

However, /pmapi/context is provided as a dedicated URL for applications wishing to explicitly create the contexts they use.

If successful, the server responds with a HTTP 200 (OK) code and JSON message body of the form:

$ curl -s http://localhost:44322/pmapi/context?\
	hostspec=www.acme.com&polltime=500 | pmjson
{
  "context": 348734,
  "source": "05af7f3eb840277fd3cfa91f90ef0067199743c",
  "hostspec": "www.acme.com",
  "labels": {
    "domainname": "acme.com",
    "groupid": 1000,
    "hostname": "www.acme.com",
    "machineid": "295b7623b6074cc8bdbda8bf96f6930a"
    "platform": "dev",
    "userid": 1000
  }
}

The context (a 32-bit unsigned decimal number) can then be used with all later requests.

In the case of a hostspec containing authentication information, such as a username, the server will follow the HTTP Basic Authentication protocol to ascertain necessary authentication details from the user, providing the client web application an opportunity to request these from the user.

The metric endpoint provides detailed PMAPI metric metadata for one or more metrics. If no parameters are supplied, the response will be for all metrics found when traversing the entire Performance Metrics Name Space (PMNS).

The prefix parameter can be used to specify a subtree of the PMNS for traversal. Alternatively, a specific metric or comma-separated list of metrics can be specified using either name or names

The server response is a JSON document that provides metric metadata as an array.

$ curl -s http://localhost:44322/pmapi/metric?\
	names=kernel.all.load,disk.all.read | pmjson
{
  "context": 348734,
  "metrics": [
    {
      "name": "kernel.all.load",
      "pmid": "60.2.0",
      "indom": "60.2",
      "type": "FLOAT",
      "sem": "instant",
      "units": "none",
      "series": "d2b28c7f6dc0d69ffd21dba7ba955e78c37719b",
      "source": "05af7f3eb840277fd3cfa91f90ef0067199743c",
      "labels": {
        "agent": "linux",
        "domainname": "acme.com",
        "groupid": 1000,
        "hostname": "www.acme.com",
        "platform": "dev",
        "userid": 1000
      },
      "text-oneline": "1, 5 and 15 minute load average"
    },
    {
      "name": "disk.all.read",
      "pmid": "60.0.24",
      "type": "U64",
      "sem": "counter",
      "units": "count",
      "series": "d2b28c7f6dc0d69ffd21dba7ba955e78c37719b",
      "source": "05af7f3eb840277fd3cfa91f90ef0067199743c",
      "labels": {
        "agent": "linux",
        "domainname": "acme.com",
        "groupid": 1000,
        "hostname": "www.acme.com",
        "platform": "dev",
        "userid": 1000
      },
      "text-oneline": "total read operations, summed for all disks",
      "text-help": "Cumulative number of disk read operations [...]"
    }
  ]
}

Most of the fields are directly transcribed from the PMAPI calls for metric descriptors, labels and help text mentioned above and are exactly as would be observed using the pminfo(1) command with the -dlmstT options.

The semantics, type and units fields are as returned by pmTypeStr(3), pmUnitsStr(3) and pmSemStr(3).

This request fetches (samples) current values for given metrics.

If any of the names or pmids provided are valid, the response is a JSON document that provides the values for all instances of the metrics, unless a instance profile has been set for the web context (see section on InDom profiles below).

$ curl -s http://localhost:44322/pmapi/fetch?\
	names=kernel.all.load,disk.all.read | pmjson
{
  "context": 348734,
  "timestamp": 1547483646.2147431,
  "values": [
    {
      "pmid": "60.2.0",
      "name": "kernel.all.load",
      "instances:" [
        { "instance": 1, "value": 0.1 },
        { "instance": 5, "value": 0.17 },
        { "instance": 15, "value": 0.22 }
      ]
    },
    {
      "pmid":"60.0.24",
      "name":"disk.all.read",
      "instances:" [
        { "instance": null, "value": 639231 }
      ]
    }
  ]
}

The response fields map directly to fields from the underlying pmFetch(3) sampling interface.

Numeric metric types are represented as JSON integer or floating-point values. Strings are passed verbatim, except that non-ASCII values are replaced with a Unicode 0xFFFD replacement character code.

In backward compatibility mode the timestamp is presented as a JSON map with second (sec) and microsecond (us) fields, instead of using the more compact floating point representation shown above.

The children endpoint provides iterative namespace traversal for a context. If no parameters are supplied, the response will describe the direct descendants of the Performance Metrics Name Space (PMNS) root.

The prefix parameter can be used to specify a subtree of the PMNS for traversal.

The server response is a JSON document that provides the set of leaf and non-leaf nodes below the given namespace node or root.

$ curl -s http://localhost:44322/pmapi/children?prefix=mem | pmjson
{
  "context": 348734,
  "name": "mem",
  "leaf": [
    "physmem",
    "freemem"
  ],
  "nonleaf": [
    "util",
    "numa",
    "vmstat",
    "buddyinfo",
    "slabinfo",
    "zoneinfo",
    "ksm"
  ]
}

This request lists the current instances of an instance domain. The instance domain is either specified directly (in numeric or string form) or indirectly, by association with the specified metric.

The request can be further qualified with a comma-separated list of the instances to report on, either by name or number, using the instance and iname parameters.

In the case of instance name qualifiers, these will be matched by exact string comparison by default. Alternatively, the match parameter can be used to specify that regular expression or glob pattern matching should be used instead.

The response is a JSON document that provides the instance domain metadata as an array.

$ curl -s http://localhost:44322/pmapi/indom?\
	name=kernel.all.load | pmjson
{
  "context": 348734,
  "indom": "60.2",
  "labels": {
    "domainname": "acme.com",
    "groupid": 1000,
    "hostname": "www.acme.com",
    "machineid": "295b7623b6074cc8bdbda8bf96f6930a"
    "platform": "dev",
    "userid": 1000
  },
  "instances": [
    {
      "instance": 1,
      "name": "1 minute"
      "labels": { ... },
    },
    {
      "instance": 5,
      "name": "5 minute"
      "labels": { ... },
    },
    {
      "instance": 15,
      "name": "15 minute"
      "labels": { ...  },
    }
  ]
}

Some PMAPI operations can be performed with an active instance domain profile which restricts (filters) the set of resulting instances returned, as described on pmAddProfile(3).

$ curl -s http://localhost:44322/pmapi/profile?\
	expr=add,indom=60.2,iname=1%20minute 
{ "context": 348734, "success": true }

Some performance metrics allow their value to be modified, for example to re-initialize counters or to modify control variables.

This operation takes a single metric name to modify, and optionally specific instances. The mandatory value will be interpreted according to the type of the metric being modified.

If successful, the response from these requests is a JSON document of the form:

$ curl -s http://localhost:44322/pmapi/store?\
	name=pmcd.control.timeout&value=10
{
  "context": 348734,
  "success": true
}

Create a new derived metric, as defined by the pmRegisterDerived(3) metric interface. Derived metrics are not associated with any particular context and must be registered before creation (or reconnect) of any context wishing to use the new metric.

This interface is one of the few that allows a POST to be used in place of a GET. In this case the HTTP POST request body may be used to provide one or more derived metrics specification (all at once, across multiple lines, as a convenience).

$ curl -s http://localhost:44322/pmapi/derive?\
	name=blkio.avgsz&expr=disk.all.blktotal/disk.all.total | pmjson
{
  "success": true
}

$ curl -s http://localhost:44322/pmapi/fetch?\
	name=blkio.avgsz&samples=2 | pmjson
{
  "context": 348734,
  "timestamp": 1547483648.2147428,
  "values": [
    {
      "pmid": "511.0.27",
      "name": "blkio.avgsz",
      "instances:" [
        {
          "instance": null,
          "value": 9231
        }
      ]
    }
  ]
}

This request is a subset of the style described in the “Open Metrics” section, allowing a web context identifier to be passed as a parameter. It is otherwise very similar in terms of parameters and response handling, please refer to the earlier section for details.