docs/best-practices/troubleshooting/profiling_debugging.md

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# Profiling and Debugging
In any real world scenario, an app might start exhibiting undesirable behavior in terms of resource spikes.
CPU/Memory spikes are not uncommon in most cases.
Dapr allows users to start an on-demand profiling session using `pprof` through its profiling server endpoint and start an instrumentation session to discover problems and issues such as concurrency, performance, cpu and memory usage.
## Enable profiling
Dapr allows you to enable profiling in both Kubernetes and Standalone modes.
### Kubernetes
To enable profiling in Kubernetes, simply add the following annotation to your Dapr annotated pod:
<pre>
annotations:
dapr.io/enabled: "true"
dapr.io/id: "rust-app"
<b>dapr.io/profiling: "true"</b>
</pre>
### Standalone
To enable profiling in Standalone mode, pass the `enable-profiling` and the `profile-port` flags to the Dapr CLI:
Note that `profile-port` is not required, and Dapr will pick an available port.
`dapr run --enable-profiling true --profile-port 7777 python myapp.py`
## Debug a profiling session
After profiloing is enabled, we can start a profiling session to investigate what's going on with the Dapr runtime.
### Kubernetes
First, find the pod containing the Dapr runtime. If you don't already know the the pod name, type `kubectl get pods`:
```
NAME READY STATUS RESTARTS AGE
divideapp-6dddf7dc74-6sq4l 2/2 Running 0 2d23h
```
If profiling has been enabled successfully, the runtime logs should show the following:
`time="2019-09-09T20:56:21Z" level=info msg="starting profiling server on port 7777"`
In this case, we want to start a session with the Dapr runtime inside of pod `divideapp-6dddf7dc74-6sq4l`.
We can do so by connecting to the pod via port forwarding:
```
kubectl port-forward divideapp-6dddf7dc74-6sq4 7777:7777
Forwarding from 127.0.0.1:7777 -> 7777
Forwarding from [::1]:7777 -> 7777
Handling connection for 7777
```
Now that the connection has been established, we can use `pprof` to profile the Dapr runtime.
The following example will create a `cpu.pprof` file containing samples from a profile session that lasts 120 seconds:
`curl "http://localhost:7777/debug/pprof/profile?seconds=120" > cpu.pprof`
Analyze the file with pprof:
```
pprof cpu.pprof
```
You can also save the results in a visualized way inside a PDF:
`go tool pprof --pdf your-binary-file http://localhost:7777/debug/pprof/profile?seconds=120 > profile.pdf`
For memory related issues, you can profile the heap:
`go tool pprof --pdf your-binary-file http://localhost:7777/debug/pprof/heap > heap.pdf`
![heap](../imgs/heap.png)
Profiling allocated objects:
```
go tool pprof http://localhost:7777/debug/pprof/heap
> exit
Saved profile in /Users/myusername/pprof/pprof.daprd.alloc_objects.alloc_space.inuse_objects.inuse_space.003.pb.gz
```
To analyze, grab the file path above (its a dynamic file path, so pay attention to note paste this one), and execute:
`go tool pprof -alloc_objects --pdf /Users/myusername/pprof/pprof.daprd.alloc_objects.alloc_space.inuse_objects.inuse_space.003.pb.gz > alloc-objects.pdf`
![alloc](../imgs/alloc.png)
### Standalone
For Standalone mode, locate the Dapr instance that you want to profile:
```
dapr list
APP ID DAPR PORT APP PORT COMMAND AGE CREATED PID
node-subscriber 3500 3000 node app.js 12s 2019-09-09 15:11.24 896
```
Grab the DAPR PORT, and if profiling has been enabled as desribed above, you can now start using `pprof` to profile Dapr.
Look at the Kubernetes examples above for some useful commands to profile Dapr.
More info on pprof can be found [here](https://github.com/google/pprof).