profefe, a continuous profiling system, collects profiling data from a fleet of running applications and provides API for querying profiling samples for postmortem performance analysis.
"Continuous Profiling and Go" describes the motivation behind profefe:
With the increase in momentum around the term “observability” over the last few years, there is a common misconception amongst the developers, that observability is exclusively about metrics, logs and tracing (a.k.a. “three pillars of observability”) [..] With metrics and tracing, we can see the system on a macro-level. Logs only cover the known parts of the system. Performance profiling is another signal that uncovers the micro-level of a system; continuous profiling allows observing how the components of the application and the infrastructure it runs in, influence the overall system.
See Design Docs documentation.
To build and start profefe collector, run:
$ make
$ ./BUILD/profefe -addr=localhost:10100 -storage-type=badger -badger.dir=/tmp/profefe-data
2019-06-06T00:07:58.499+0200 info profefe/main.go:86 server is running {"addr": ":10100"}
The command above starts profefe collector backed by BadgerDB as a storage for profiles. profefe supports other storage types: S3, Google Cloud Storage and ClickHouse.
Run ./BUILD/profefe -help
to show the list of all available options.
profefe ships with a fork of Google Stackdriver Profiler's example application, modified to use profefe agent, that sends profiling data to profefe collector.
To start the example application run the following command in a separate terminal window:
$ go run ./examples/hotapp/main.go
After a brief period, the application will start sending CPU profiles to profefe collector.
send profile: http://localhost:10100/api/0/profiles?service=hotapp-service&labels=version=1.0.0&type=cpu
send profile: http://localhost:10100/api/0/profiles?service=hotapp-service&labels=version=1.0.0&type=cpu
send profile: http://localhost:10100/api/0/profiles?service=hotapp-service&labels=version=1.0.0&type=cpu
With profiling data persisted, query the profiles from the collector using its HTTP API (refer to documentation for collector's HTTP API below). As an example, request all profiling data associated with the given meta-information (service name and a time frame), as a single merged profile:
$ go tool pprof 'http://localhost:10100/api/0/profiles/merge?service=hotapp-service&type=cpu&from=2019-05-30T11:49:00&to=2019-05-30T12:49:00&labels=version=1.0.0'
Fetching profile over HTTP from http://localhost:10100/api/0/profiles...
Saved profile in /Users/varankinv/pprof/pprof.samples.cpu.001.pb.gz
Type: cpu
(pprof) top
Showing nodes accounting for 43080ms, 99.15% of 43450ms total
Dropped 53 nodes (cum <= 217.25ms)
Showing top 10 nodes out of 12
flat flat% sum% cum cum%
42220ms 97.17% 97.17% 42220ms 97.17% main.load
860ms 1.98% 99.15% 860ms 1.98% runtime.nanotime
0 0% 99.15% 21050ms 48.45% main.bar
0 0% 99.15% 21170ms 48.72% main.baz
0 0% 99.15% 42250ms 97.24% main.busyloop
0 0% 99.15% 21010ms 48.35% main.foo1
0 0% 99.15% 21240ms 48.88% main.foo2
0 0% 99.15% 42250ms 97.24% main.main
0 0% 99.15% 42250ms 97.24% runtime.main
0 0% 99.15% 1020ms 2.35% runtime.mstart
profefe includes a tool, that allows importing existing pprof data into the collector. While profefe collector is still running, run the following:
$ ./scripts/pprof_import.sh --service service1 --label region=europe-west3 --label host=backend1 --type cpu -- path/to/cpu.prof
uploading service1-cpu-backend1-20190313-0948Z.prof...OK
You can build a docker image with profefe collector, by running the command:
$ make docker-image
The documentation about running profefe in docker is in contrib/docker/README.md.
POST /api/0/profiles?service=<service>&type=[cpu|heap|...]&labels=<key=value,key=value>
body pprof.pb.gz
< HTTP/1.1 200 OK
< Content-Type: application/json
<
{
"code": 200,
"body": {
"id": <id>,
"type": <type>,
···
}
}
service
— service name (string)type
— profile type ("cpu", "heap", "block", "mutex", "goroutine", "threadcreate", or "other")labels
— a set of key-value pairs, e.g. "region=europe-west3,dc=fra,ip=1.2.3.4,version=1.0" (Optional)
Example
$ curl -XPOST \
"http://<profefe>/api/0/profiles?service=api-backend&type=cpu&labels=region=europe-west3,dc=fra" \
--data-binary "@$HOME/pprof/api-backend-cpu.prof"
Go's runtime traces are a special case of profiling data, that can be stored and queried with profefe.
Currently, profefe doesn't support extracting the timestamp of when the trace was created. Client may provide
this information via created_at
parameter, see below.
POST /api/0/profiles?service=<service>&type=trace&created_at=<created_at>&labels=<key=value,key=value>
body trace.out
< HTTP/1.1 200 OK
< Content-Type: application/json
<
{
"code": 200,
"body": {
"id": <id>,
"type": "trace",
···
}
}
service
— service name (string)type
— profile type ("trace")created_at
— trace profile creation time, e.g. "2006-01-02T15:04:05" (defaults to server's current time)labels
— a set of key-value pairs, e.g. "region=europe-west3,dc=fra,ip=1.2.3.4,version=1.0" (Optional)
Example
$ curl -XPOST \
"http://<profefe>/api/0/profiles?service=api-backend&type=trace&created_at=2019-05-01T18:45:00&labels=region=europe-west3,dc=fra" \
--data-binary "@$HOME/pprof/api-backend-trace.out"
GET /api/0/profiles?service=<service>&type=<type>&from=<created_from>&to=<created_to>&labels=<key=value,key=value>
< HTTP/1.1 200 OK
< Content-Type: application/json
<
{
"code": 200,
"body": [
{
"id": <id>,
"type": <type>
},
···
]
}
service
— service namefrom
,to
— a time frame in which profiling data was collected, e.g. "from=2006-01-02T15:04:05"type
— profile type ("cpu", "heap", "block", "mutex", "goroutine", "threadcreate", "trace", "other") (Optional)labels
— a set of key-value pairs, e.g. "region=europe-west3,dc=fra,ip=1.2.3.4,version=1.0" (Optional)
Example
$ curl "http://<profefe>/api/0/profiles?service=api-backend&type=cpu&from=2019-05-01T17:00:00&to=2019-05-25T00:00:00"
GET /api/0/profiles/merge?service=<service>&type=<type>&from=<created_from>&to=<created_to>&labels=<key=value,key=value>
< HTTP/1.1 200 OK
< Content-Type: application/octet-stream
< Content-Disposition: attachment; filename="pprof.pb.gz"
<
pprof.pb.gz
Request parameters are the same as for querying meta information.
Note, "type" parameter is required; merging runtime traces is not supported.
GET /api/0/profiles/<id>
< HTTP/1.1 200 OK
< Content-Type: application/octet-stream
< Content-Disposition: attachment; filename="pprof.pb.gz"
<
pprof.pb.gz
id
- id of stored profile, returned with the request for meta information above
GET /api/0/profiles/<id1>+<id2>+...
< HTTP/1.1 200 OK
< Content-Type: application/octet-stream
< Content-Disposition: attachment; filename="pprof.pb.gz"
<
pprof.pb.gz
id1
,id2
- ids of stored profiles
Note, merging is possible only for profiles of the same type; merging runtime traces is not supported.
GET /api/0/services
< HTTP/1.1 200 OK
< Content-Type: application/json
<
{
"code": 200,
"body": [
<service1>,
···
]
}
GET /api/0/version
< HTTP/1.1 200 OK
< Content-Type: application/json
<
{
"code": 200,
"body": {
"version": <version>,
"commit": <git revision>,
"build_time": <build timestamp>"
}
}
Profiling always comes with some costs. Go collects sampling-based profiling data and for the most applications the real overhead is small enough (refer to "Can I profile my production services" from Go's Diagnostics documentation).
To reduce the costs, users can adjust the frequency of collection rounds, e.g. collect 10 seconds of CPU profiles every 5 minutes.
profefe-agent tries to reduce the overhead further by adding a small jiggling in-between the profiles collection rounds. This distributes the total profiling overhead, making sure that not all instances of application's cluster are being profiled at the same time.
profefe collects pprof-formatted profiling data. The format is used by Go profiler,
but thrid-party profilers for other programming languages support of the format too. For example, google/pprof-nodejs
for Node.js,
tikv/pprof-rs
for Rust, arnaud-lb/php-memory-profiler
for PHP, etc.
Integrating those is the subject of building a transport layer between the profiler and profefe.
While the topic of continuous profiling in the production is quite unrepresented in the public internet, some research and commercial projects already exist:
- Stackdriver profiler
- Google-Wide Profiling: A Continuous Profiling Infrastructure for Data Centers (paper)
- StackImpact
- conprof
- Opsian - Continuous Profiling for JVM (provides on-premises plan for enterprise customers)
- Liveprof - Continuous Profiling for PHP (RUS)
- FlameScope
profefe is still in its early state. Feedback and contribution are very welcome.
MIT