Provided by: libpcp3-dev_5.0.3-1_amd64 
NAME
PMWEBAPI - introduction to the Performance Metrics Web Application Programming Interface
HTTP SYNOPSIS
GET /metrics
GET /series/...
GET /pmapi/...
C SYNOPSIS
#include <pcp/pmwebapi.h>
... assorted routines ...
cc ... -lpcp_web -lpcp
DESCRIPTION
The PMWEBAPI is a collection of interfaces providing Performance Co-Pilot services for web applications.
It consists of APIs for web applications querying and analysing both live and historical performance
data, as well as APIs used by web servers.
The usual HTTP URL-encoded optional parameter rules apply and PMWEBAPI REST requests always follow the
convention:
/api/endpoint?parameter1=value1¶meter2=value2
Examples in all following sections use the curl(1) command line utility with a local pmproxy(1) server
listening on port 44322 (default port). The pmjson(1) utility is used to neatly format any JSON output,
as opposed to the compact (minimal whitespace) form provided by default. The examples in the scalable
time series section use historical data recorded by the pmlogger(1) service, in conjunction with a local
redis-server(1).
OPEN METRICS
Exporting of live performance metrics in an Open Metrics compatible format (as described at
https://openmetrics.io and popularized by the https://prometheus.io project) is available.
GET /metrics
┌───────────┬─────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼─────────┼────────────────────────────────────────────────┤
│names │ string │ Comma-separated list of metric names │
│times │ boolean │ Append sample times (milliseconds since epoch) │
└───────────┴─────────┴────────────────────────────────────────────────┘
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
SCALABLE TIME SERIES
The fast, scalable time series query capabilities provided by the pmseries(1) command are also available
through a REST API. These queries provide access to performance data (metric metadata and values) from
multiple hosts simultaneously, and in a fashion suited to efficient retrieval by any number of web
applications.
All requests in this group can be accompanied by an optional client parameter. The value passed in the
request will be sent back in the response - all responses will be in JSON object form in this case, with
top level "client" and "result" fields.
GET /series/query - pmSeriesQuery(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│expr │ string │ Query string in pmseries(1) format │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
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"
}
]
GET /series/values - pmSeriesValues(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│series │ string │ Comma-separated list of series identifiers │
│client │ string │ Request identifier sent back with response │
├───────────┼────────┼────────────────────────────────────────────┤
│samples │ number │ Count of samples to return │
│interval │ string │ Time between successive samples │
│start │ string │ Sample window start time │
│finish │ string │ Sample window end time │
│offset │ string │ Sample window offset │
│align │ string │ Sample time alignment │
│zone │ string │ Time window timezone │
└───────────┴────────┴────────────────────────────────────────────┘
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"
}
]
GET /series/descs - pmSeriesDescs(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│series │ string │ Comma-separated list of series identifiers │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
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",
}
]
GET /series/labels - pmSeriesLabels(3), pmSeriesLabelValues(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│series │ string │ Comma-separated list of series identifiers │
│match │ string │ Glob pattern string to match on all labels │
│name │ string │ Find all known label values for given name │
│names │ string │ Comma-separated list of label names │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
This command operates in one of three modes. It can perform a label set lookup for one or more time
series identifiers, when given the series parameter). It can produce a list of all known label names, in
the absense of name, names or series parameters. The JSON responses for these modes contains the same
information as the pmseries -l/--labels option.
Alternatively, it can produce a list of all known label values for a given label name or names. The JSON
response for this mode contains the same information as the pmseries -v/--values 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 name, names or series parameters, 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"
]
Use the name or names parameters to find all possible label values for the given name(s).
$ curl -s http://localhost:44322/series/labels?\
names=hostname,domainname | pmjson
{
"hostname": [ "app", "nas" ],
"domainname": [ "acme.com" ]
}
GET /series/metrics - pmSeriesMetrics(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│series │ string │ Comma-separated list of series identifiers │
│match │ string │ Glob pattern string to match on all names │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
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",
...
]
GET /series/sources - pmSeriesSources(3)
┌───────────┬────────┬─────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼─────────────────────────────────────────────┤
│series │ string │ Comma-separated list of source identifiers │
│match │ string │ Glob pattern string to match on all sources │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴─────────────────────────────────────────────┘
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"
]
}
]
GET /series/instances - pmSeriesInstances(3)
┌───────────┬────────┬───────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼───────────────────────────────────────────────┤
│series │ string │ Comma-separated list of series identifiers │
│match │ string │ Glob pattern string to match on all instances │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴───────────────────────────────────────────────┘
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",
...
]
GET /series/load - pmSeriesLoad(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│expr │ string │ Source load string in pmseries(1) format │
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
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
}
PMAPI HOST SERVICES
The live performance collection facilities available from pmcd(1) can also be accessed through a REST
API.
All requests are performed on the web server host by default, unless either a hostspec or context
parameter is provided. hostname can be used in place of hostspec.
Context identifiers are used as a persistent way to refer to PMAPI contexts across related web requests.
These contexts expire after a configurable period of disuse, and are explicitly allocated using the
/pmapi/context interface.
The timeout interval is configurable at context creation time, and as such the polltime parameter can be
used anywhere the hostspec is specified. It sets the context timeout in terms of length of inactive
time. The unit for the timeout value is seconds.
To specify a specific existing context in any PMAPI web request, the endpoints can be accessed with
either the context parameter or enbedded in the endpoint URL itself, such as /pmapi/[number]/fetch.
GET /pmapi/context - pmNewContext(3)
┌────────────┬────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│polltimeout │ number │ Seconds of inactivity before closing context │
│client │ string │ Request identifier sent back with response │
└────────────┴────────┴────────────────────────────────────────────────┘
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.
GET /pmapi/metric - pmLookupDesc(3), pmLookupLabels(3), pmLookupName(3), pmLookupText(3)
┌────────────┬────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────────────────┤
│name │ string │ An individual metric name │
│names │ string │ Comma-separated list of metric names │
│pmid │ pmID │ Numeric or pmIDStr(3) metric identifier │
│pmids │ string │ Comma-separated numeric or pmIDStr(3) pmIDs │
│prefix │ string │ Metric namespace component as in PMNS(5) │
├────────────┼────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number (optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴────────┴────────────────────────────────────────────────┘
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).
GET /pmapi/fetch - pmFetch(3)
┌────────────┬────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────────────────┤
│delta │ string │ Sampling interval in pmParseInterval(3) form │
│name │ string │ An individual metric name │
│names │ string │ Comma-separated list of metric names │
│pmid │ pmID │ Numeric or pmIDStr(3) metric identifier │
│pmids │ string │ Comma-separated numeric or pmIDStr(3) pmIDs │
├────────────┼────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number (optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴────────┴────────────────────────────────────────────────┘
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.
GET /pmapi/children - pmGetChildren(3), pmGetChildrenStatus(3)
┌────────────┬────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────────────────┤
│prefix │ string │ Metric namespace component as in PMNS(5) │
├────────────┼────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number (optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴────────┴────────────────────────────────────────────────┘
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"
]
}
GET /pmapi/indom - pmGetInDom(3), pmNameInDom(3), pmLookupInDom(3)
┌────────────┬─────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼─────────┼────────────────────────────────────────────────┤
│iname │ string │ Comma-separated list of instance names │
│indom │ pmInDom │ Numeric or pmInDomStr(3) instance domain │
│instance │ number │ Comma-separated list of instance numbers │
│match │ string │ Pattern matching style (exact, glob or regex) │
│name │ string │ An individual metric name │
├────────────┼─────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number (optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴─────────┴────────────────────────────────────────────────┘
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": { ... },
}
]
}
GET /pmapi/profile - pmAddProfile(3), pmDelProfile(3)
┌────────────┬─────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼─────────┼────────────────────────────────────────────────┤
│iname │ string │ Comma-separated list of instance names │
│indom │ pmInDom │ Numeric or pmInDomStr(3) instance domain │
│instance │ number │ Comma-separated list of instance numbers │
│expr │ string │ One of "add" or "del" (mandatory). │
│match │ string │ Pattern matching style (exact, glob or regex) │
├────────────┼─────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number (optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴─────────┴────────────────────────────────────────────────┘
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 }
GET /pmapi/store - pmStore(3)
┌────────────┬────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────────────────┤
│iname │ string │ Comma-separated list of instance names │
│instance │ number │ Comma-separated list of instance numbers │
│name │ string │ An individual metric name │
│value │ (any) │ New value for the given metric instance(s) │
├────────────┼────────┼────────────────────────────────────────────────┤
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│context │ number │ Web context number optional like hostspec) │
│polltimeout │ number │ Seconds of inactivity before context closed │
└────────────┴────────┴────────────────────────────────────────────────┘
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
}
GET /pmapi/derive: pmRegisterDerived(3)
┌───────────┬────────┬────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├───────────┼────────┼────────────────────────────────────────────┤
│expr │ string │ Derived metric expression │
│name │ string │ New derived metric name │
├───────────┼────────┼────────────────────────────────────────────┤
│client │ string │ Request identifier sent back with response │
└───────────┴────────┴────────────────────────────────────────────┘
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
}
]
}
]
}
GET /pmapi/metrics: pmLookupDesc(3),pmLookupLabels(3), pmFetch(3)
┌────────────┬─────────┬────────────────────────────────────────────────┐
│Parameters │ Type │ Explanation │
├────────────┼─────────┼────────────────────────────────────────────────┤
│names │ string │ Comma-separated list of metric names │
│times │ boolean │ Append sample times (milliseconds since epoch) │
├────────────┼─────────┼────────────────────────────────────────────────┤
│context │ number │ Web context number (optional like hostspec) │
│hostspec │ string │ Host specification as described in PCPIntro(1) │
│polltimeout │ number │ Seconds of inactivity before context closed │
│client │ string │ Request identifier sent back with response │
└────────────┴─────────┴────────────────────────────────────────────────┘
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.
NOTES
For the REST APIs, errors generally result in HTTP-level error responses. Wherever possible, any PMAPI
error string will also be provided in a message along with the response.
All responses will be returned using HTTP 1.1 protocol and with chunked encoding being used to stream
responses that are larger than a configured maximum size. Compression will be used on responses whenever
the client indicates appropriate support.
An Access-Control-Allow-Origin: * header is added to all REST API responses.
SEE ALSO
PCPIntro(1), curl(1), pmcd(1), pmdaopenmetrics(1), pminfo(1), pmjson(1), pmlogger(1), pmproxy(1),
pmseries(1), redis-server(1), PCPIntro(3) and PMAPI(3)