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NAME | HTTP SYNOPSIS | C SYNOPSIS | DESCRIPTION | OPEN METRICS | SCALABLE TIME SERIES | FULL TEXT SEARCH | PMAPI HOST SERVICES | NOTES | SEE ALSO | COLOPHON |
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PMWEBAPI(3) Library Functions Manual PMWEBAPI(3)
PMWEBAPI - introduction to the Performance Metrics Web
Application Programming Interface
GET /metrics
GET /series/...
GET /search/...
GET /pmapi/...
#include <pcp/pmwebapi.h>
... assorted routines ...
cc ... -lpcp_web -lpcp
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).
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.
All requests are performed on the web server host by default,
unless a hostspec parameter is provided.
GET /metrics
┌────────────┬─────────┬────────────────────────────────────────────────┐
│ Parameters │ Type │ Explanation │
├────────────┼─────────┼────────────────────────────────────────────────┤
│ names │ string │ Comma-separated list of metric names │
│ times │ boolean │ Append sample times (milliseconds since epoch) │
├────────────┼─────────┼────────────────────────────────────────────────┤
│ hostspec │ string │ Host specification as described in PCPIntro(1) │
└────────────┴─────────┴────────────────────────────────────────────────┘
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 ingested 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
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.
REST API clients can optionally submit an URL-encoded query
string in the body of the HTTP request unless otherwise noted.
In this case the POST method must be used instead of the GET
method.
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 op‐
tions 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 identi‐
fiers. The JSON response contains the same information as the
pmseries -q/--query option using any of the time window parame‐
ters 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 identi‐
fiers. 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 absence 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 val‐
ues 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 identi‐
fiers. 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 se‐
ries from that source. The JSON response contains the same in‐
formation 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 se‐
ries identifiers. The JSON response contains the same informa‐
tion 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 pm‐
series -l/--load option.
$ curl -s http://localhost:44322/series/load?expr={source.name:"/var/log/pcp/pmlogger/acme"}
{
"success": true
}
The full text search capabilities provided by the pmsearch(1)
command are also available through a REST API. These queries
provide access to an index over performance metric names, in‐
stances, instance domains and help text, suitable for a metric
search engine, and in a fashion suited to efficient querying by
any number of web applications.
In order to use this functionality, the optional RediSearch mod‐
ule must be loaded in the redis-server at the time pmproxy is
started, such that metrics, instances and help text it discovers
can be automatically indexed.
GET /search/text - pmSearchTextQuery(3)
┌────────────┬────────┬─────────────────────────────────────────────┐
│ Parameters │ Type │ Explanation │
├────────────┼────────┼─────────────────────────────────────────────┤
│ query │ string │ Query string in pmsearch(1) format │
│ highlight │ fields │ Include matching markup in response fields │
│ offset │ number │ Result offset cursor for pagination │
│ limit │ number │ Maximum results to include in response │
│ field │ fields │ Queried fields (defaults to all) │
│ return │ fields │ Fields to actually return (defaults to all) │
│ type │ types │ Entity types to filter (defaults to all) │
└────────────┴────────┴─────────────────────────────────────────────┘
Performs a text search query across metrics and instance domains
- all forms of names and help texts.
The mandatory search string is further described in pmsearch(1)
and is passed to the server via the query parameter (HTTP GET).
$ curl -s http://localhost:44322/search/text?query=halt | pmjson
{
"total": 2,
"offset": 0,
"limit": 10,
"elapsed": 0.000504,
"results": [
{
"name": "kvm.halt_exits",
"type": "metric",
"indom": "95.0.4",
"oneline": "Number of guest exits due to halt calls.",
"helptext": "This type of exit is usually seen when a guest is idle."
},
{
"name": "kvm.halt_wakeup",
"type": "metric",
"indom": "95.0.6",
"oneline": "Number of wakeups from a halt.",
}
]
}
The available search entity types are metric, indom and instance.
Query parameters highlight and field take name, oneline and help‐
text.
Query parameter return takes name, type, oneline, helptext, in‐
dom. There is typically both a name and help text associated
with metrics. Contents of these are then matched against query.
An instance domain has help text and a numeric identifier, while
instances have a name only (which can be searched).
GET /search/suggest - pmSearchTextSuggest(3)
┌────────────┬────────┬────────────────────────────────────┐
│ Parameters │ Type │ Explanation │
├────────────┼────────┼────────────────────────────────────┤
│ query │ string │ Search query for search engine │
│ limit │ number │ Max results to include in response │
└────────────┴────────┴────────────────────────────────────┘
Provides search query suggestions, that is, metric and instance
names.
The mandatory search string is further described in pmsearch(1)
and is passed to the server via the query parameter (HTTP GET).
$ curl -s http://localhost:44322/search/suggest?query=disk&limit=4 | pmjson
[
"disk.all.avactive",
"disk.all.aveq",
"disk.all.blkread",
"disk.all.blktotal"
]
GET /search/indom - pmSearchTextInDom(3)
┌────────────┬────────┬─────────────────────────────────────┐
│ Parameters │ Type │ Explanation │
├────────────┼────────┼─────────────────────────────────────┤
│ query │ string │ Target indom for search engine │
│ offset │ number │ Result offset cursor for pagination │
│ limit │ number │ M results to include in response │
└────────────┴────────┴─────────────────────────────────────┘
Provides all entities (instances, metrics) related to indom, in‐
cluding itself, that is passed to the server via the query para‐
meter.
GET /search/info - pmSearchInfo(3)
Provides metrics relating to operation of the search engine, in
particular showing document and text record counts.
$ curl -s http://localhost:44322/search/info | pmjson
{
"docs": 1589,
"terms": 3855,
"records": 116831,
"records_per_doc_avg": 73.52,
"bytes_per_record_avg": 6.36,
"inverted_sz_mb": 0.71,
"inverted_cap_mb": 0.00,
"inverted_cap_ovh": 0.00,
"skip_index_size_mb": 0.00,
"score_index_size_mb": 0.00,
"offsets_per_term_avg": 9.41,
"offset_bits_per_record_avg": 8.00
}
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, un‐
less either a hostspec or context parameter is provided. host‐
name 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 ex‐
pire after a configurable period of disuse, and are either ex‐
plicitly allocated using the /pmapi/context interface, or implic‐
itly allocated using other interfaces.
The timeout interval is configurable at context creation time,
and as such the polltimeout 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 sec‐
onds and the default is 5.
To specify a specific existing context in any PMAPI web request,
the endpoints can be accessed with either the context parameter
or embedded in the endpoint URL itself, such as /pmapi/[num‐
ber]/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 parame‐
ter). 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 appli‐
cations 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&polltimeout=0.5 | 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 Authen‐
tication protocol to ascertain necessary authentication details
from the user, providing the client web application an opportuni‐
ty 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 Perfor‐
mance 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-sepa‐
rated list of metrics can be specified using either name or names
The server response is a JSON document that provides metric meta‐
data 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 con‐
text (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 de‐
scribe 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 pa‐
rameter 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 in‐
stances 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 │
│ client │ string │ Request identifier sent back with response │
└─────────────┴────────┴────────────────────────────────────────────────┘
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 option‐
ally 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 docu‐
ment of the form:
$ curl -s http://localhost:44322/pmapi/store?name=pmcd.control.timeout&value=10
{
"context": 348734,
"success": true
}
GET /pmapi/derive: pmAddDerived(3)
┌─────────────┬────────┬────────────────────────────────────────────────┐
│ Parameters │ Type │ Explanation │
├─────────────┼────────┼────────────────────────────────────────────────┤
│ expr │ string │ Derived metric expression │
│ name │ string │ New derived 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 │
└─────────────┴────────┴────────────────────────────────────────────────┘
Create a new derived metric, as defined by the pmAddDerived(3)
metric interface. Derived metrics are associated with the named
context, or a new context is created and returned in the result.
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 specifications (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
{
"context": 348734,
"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 parame‐
ters and response handling, please refer to the earlier section
for details.
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 re‐
sponses whenever the client indicates appropriate support.
An Access-Control-Allow-Origin: * header is added to all REST API
responses.
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)
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's
upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2024-06-14.
(At that time, the date of the most recent commit that was found
in the repository was 2024-06-14.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMWEBAPI(3)
Pages that refer to this page: pcpcompat(1), pmdaopenmetrics(1), pmfind(1), pmjson(1), pmproxy(1), pmseries(1), pmapi(3), pmda(3), pmdiscoversetup(3), pmhttpnewclient(3), pmsearchinfo(3), pmsearchsetup(3), pmsearchtextindom(3), pmsearchtextquery(3), pmsearchtextsuggest(3), pmseriesdescs(3), pmseriesquery(3), pmseriessetup(3), pmwebtimerregister(3)
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