p4app v2 #54
p4app v2 #54
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@theojepsen : Can you update the top-level README.md to provide details on how to use this new version?
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@robertsoule-barefoot Please see the updated top-level README |
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| # object hook for josn library, use str instead of unicode object |
docker/scripts/p4runtime_switch.py
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| self.grpc_port = P4RuntimeSwitch.next_grpc_port | ||
| P4RuntimeSwitch.next_grpc_port += 1 | ||
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| if thrift_port is not None: |
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simple_switch_grpc does not support the Thrift RPC server by default
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I think whoever wrote the P4RuntimeSwitch class based it on P4Switch. As you mentioned, the simple_switch_grpc target doesn't support Thrift by default. However, according to the target's README, it could support Thrift, so I think we should keep this code in.
docker/scripts/p4runtime_switch.py
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| for _ in range(SWITCH_START_TIMEOUT * 2): | ||
| if not os.path.exists(os.path.join("/proc", str(pid))): | ||
| return False | ||
| if check_listening_on_port(self.grpc_port): |
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I kind of think that it's better to actually attempt the connection even if you have access to open ports
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The point of this code is to wait for the switch to start before attempting a connection. I think the original author of this code (@sethfowler ?) put it in for a reason.
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| #!/usr/bin/env python2 | |||
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I'm actually starting to doubt that this file is used anywhere?
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No. It was copied in from p4lang/tutorials. I removed the file.
docker/scripts/p4runtime_switch.py
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| info(tableEntryToString(entry)) | ||
| self.insertTableEntry(entry) | ||
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| def insertTableEntry(self, entry=None, |
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obviously a lot of P4Runtime functionalities are missing from this class. I imagine support can be added as time goes by, but I believe that the app should also have access to the underlying P4Runtime connection.
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I forgot to mention it my review, please make sure you squash your commits before merging. |
We have received a lot of feedback about using p4app. The theme of most of the feedback is having more control over running a p4app. People are used to using Mininet, and expect the same flexibility from p4app. This was difficult with p4app's previous design, which only exposed a JSON configuration file to the user. If you wanted more functionality, you would have to hack the p4app scripts.
The new version of p4app gives you more control. Instead of writing a JSON manifest file, you write your p4app using a python script, just the way you would use mininet. p4app is now a python library that wraps-up mininet, providing helpers for compiling your P4 program and setting up the topology.
The simplest example is a switch that behaves like a wire:
https://github.com/theojepsen/p4app/blob/tj/v2/examples/wire.p4app/main.py
p4app also uses P4Runtime for configuring the switch:
https://github.com/theojepsen/p4app/blob/tj/v2/examples/ring.p4app/main.py#L32
Both P4-14 and P4-16 are supported:
https://github.com/theojepsen/p4app/blob/tj/v2/examples/compile-only.p4app/main.py
You can run different P4 programs on different switches:
https://github.com/theojepsen/p4app/blob/tj/v2/examples/two-programs.p4app/main.py#L24
You can also use P4Runtime to read counters and setup multicast groups:
https://github.com/theojepsen/p4app/blob/tj/v2/examples/counter.p4app/main.py#L13
https://github.com/theojepsen/p4app/blob/tj/v2/examples/multicast.p4app/main.py#L44