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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 |
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.
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
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 sin‐
gle 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 re‐
sponses 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 identi‐
fiers. The JSON response contains the same information as the pm‐
series -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
}
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, instances, 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 module
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 helptext.
Query parameter return takes name, type, oneline, helptext, indom.
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, includ‐
ing itself, that is passed to the server via the query parameter.
GET /search/info - pmSearchInfo(3)
Provides metrics relating to operation of the search engine, in par‐
ticular 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, 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 either explicitly allocated
using the /pmapi/context interface, or implicitly allocated using
other interfaces.
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 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
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 ex‐
actly as would be observed using the pminfo(1) command with the -dlm‐
stT 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 met‐
rics, 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 in‐
stance and iname parameters.
In the case of instance name qualifiers, these will be matched by ex‐
act string comparison by default. Alternatively, the match parameter
can be used to specify that regular expression or glob pattern match‐
ing 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 re‐
turned, 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 exam‐
ple 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 accord‐
ing 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 par‐
ticular 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 MET‐
RICS'' 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.
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 re‐
sponses.
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.
Information 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
2020-08-13. (At that time, the date of the most recent commit that
was found in the repository was 2020-08-11.) 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: pmDiscoverClose(3) , pmDiscoverSetConfiguration(3) , pmDiscoverSetEventLoop(3) , pmDiscoverSetMetricRegistry(3) , pmDiscoverSetSlots(3) , pmdiscoversetup(3) , pmDiscoverSetup(3)