The charm size got 10x bigger due to cygrpc.cpython-38-x86_64-linux-gnu.so with debug symbols

[nobuto-m]

Bug Description

As you can see blow, the charm size got 10x bigger in candidate/beta/edge compared to the stable one.

$ juju info prometheus-k8s

...

channels: |
  latest/stable:     129  2023-09-04  (129)  10MB   amd64  ubuntu@20.04
  latest/candidate:  146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04
  latest/beta:       146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04
  latest/edge:       153  2023-10-20  (153)  124MB  amd64  ubuntu@20.04
  1.0/stable:        129  2023-09-11  (129)  10MB   amd64  ubuntu@20.04
  1.0/candidate:     146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04
  1.0/beta:          146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04
  1.0/edge:          146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04

By looking into the content, the dominant factor is the following file in non stable ones.

$ du -h prometheus-k8s_edge/venv/grpc/_cython/cygrpc.cpython-38-x86_64-linux-gnu.so 
297M	prometheus-k8s_edge/venv/grpc/_cython/cygrpc.cpython-38-x86_64-linux-gnu.so

After looking up the internet (grpc/grpc#21958), there was a hint that the binary may contain the debug info in it. And indeed, stripping the debug info by hand trimmed down the size significantly.

$ strip --strip-debug prometheus-k8s_edge/venv/grpc/_cython/cygrpc.cpython-38-x86_64-linux-gnu.so 

$ du -h prometheus-k8s_edge/venv/grpc/_cython/cygrpc.cpython-38-x86_64-linux-gnu.so 
14M	prometheus-k8s_edge/venv/grpc/_cython/cygrpc.cpython-38-x86_64-linux-gnu.so

Not so sure how to fix the situation properly in this charm though.

To Reproduce

$ juju download --channel 1.0/stable prometheus-k8s
Base "ubuntu@22.04" is not supported for charm "prometheus-k8s", trying base "ubuntu@20.04"
Fetching charm "prometheus-k8s" revision 129 using "1.0/stable" channel and base "amd64/ubuntu/20.04"
Install the "prometheus-k8s" charm with:
    juju deploy ./prometheus-k8s_r129.charm

$ unzip -d prometheus-k8s_stable ./prometheus-k8s_r129.charm

$ juju download --channel 1.0/edge prometheus-k8s
Base "ubuntu@22.04" is not supported for charm "prometheus-k8s", trying base "ubuntu@20.04"
Fetching charm "prometheus-k8s" revision 146 using "1.0/edge" channel and base "amd64/ubuntu/20.04"
Install the "prometheus-k8s" charm with:
    juju deploy ./prometheus-k8s_r146.charm

$ unzip -d prometheus-k8s_edge ./prometheus-k8s_r146.charm

$ du -sh prometheus-k8s_*/
381M	prometheus-k8s_edge/
36M	prometheus-k8s_stable/

Environment

  1.0/stable:        129  2023-09-11  (129)  10MB   amd64  ubuntu@20.04
  1.0/edge:          146  2023-09-11  (146)  123MB  amd64  ubuntu@20.04

Relevant log output

N/A

Additional context

No response

[mmkay]

Most likely this is related to charm tracing support introduction in the prometheus charm which uses gRPC to communicate with tempo. We're investigating switching to another protocol in canonical/tempo-k8s-operator#53.

[mmkay]

After #569, latest edge release is 27MB. It's more than 10MB as there are new libraries included, but it's not 127 MB anymore.

channels: |
  latest/stable:     159  2024-01-16  (159)  125MB  amd64  ubuntu@20.04
  latest/candidate:  165  2024-01-16  (165)  127MB  amd64  ubuntu@20.04
  latest/beta:       165  2024-01-16  (165)  127MB  amd64  ubuntu@20.04
  latest/edge:       170  2024-02-01  (170)  27MB   amd64  ubuntu@20.04
  1.0/stable:        156  2023-12-12  (156)  124MB  amd64  ubuntu@20.04
  1.0/candidate:     159  2023-12-12  (159)  125MB  amd64  ubuntu@20.04
  1.0/beta:          159  2023-12-12  (159)  125MB  amd64  ubuntu@20.04
  1.0/edge:          159  2023-12-12  (159)  125MB  amd64  ubuntu@20.04