fix(snap): Install Unit of Measure config file on upgrade

[farshidtz]

PR #4119 added the following environment variable:

edgex-go/snap/snapcraft.yaml

Line 278 in 166620d

UOM_UOMFILE: $SNAP_DATA/config/core-metadata/res/uom.toml

This makes the edge releases of snap backward incompatible as of v2.3.0-dev.45 because this file doesn't exist when upgrading from an older version. The latest snap beta release which isn't broken is 2.3.0-dev.44 (snap rev 5898/5899). This fix works when upgrading from the latest beta or older.

This PR adds the logic to add the configuration file when upgrading (i.e. using snap refresh).

Signed-off-by: Farshid Tavakolizadeh farshid.tavakolizadeh@canonical.com

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/edgex-go/blob/main/.github/Contributing.md

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• I have opened a PR for the related docs change (if not, why?)

Testing Instructions

Reproduce the error:

$ snap install edgexfoundry --channel=latest/stable
edgexfoundry 2.2.0+2 from Canonical✓ installed

$ snap refresh edgexfoundry --channel=latest/edge
edgexfoundry (edge) 2.3.0-dev.46 from Canonical✓ refreshed

$ snap logs -n 100 edgexfoundry.core-metadata | grep -i ERROR
2022-08-15T16:16:26+02:00 edgexfoundry.core-metadata[386550]: level=ERROR ts=2022-08-15T14:16:26.714636738Z app=core-metadata source=httpserver.go:143 msg="Web server failed: http: Server closed"
2022-08-15T16:17:40+02:00 edgexfoundry.core-metadata[388065]: level=ERROR ts=2022-08-15T14:17:40.24683483Z app=core-metadata source=bootstrap.go:42 msg="could not load unit of measure configuration file (/var/snap/edgexfoundry/3904/config/core-metadata/res/uom.toml): open /var/snap/edgexfoundry/3904/config/core-metadata/res/uom.toml: no such file or directory"

Test the changes using the snap built from this branch:

$ snap install edgexfoundry --channel=latest/stable
edgexfoundry 2.2.0+2 from Canonical✓ installed

$ snap refresh edgexfoundry --channel=latest/edge/pr-4125
edgexfoundry (edge/pr-4125) 2.3.0-dev.46 from Canonical✓ refreshed

$ snap logs -n 2 edgexfoundry.core-metadata 
2022-08-15T16:25:57+02:00 edgexfoundry.core-metadata[395550]: level=INFO ts=2022-08-15T14:25:57.308622394Z app=core-metadata source=message.go:55 msg="This is the EdgeX Core Metadata Microservice"
2022-08-15T16:25:57+02:00 edgexfoundry.core-metadata[395550]: level=INFO ts=2022-08-15T14:25:57.308628766Z app=core-metadata source=message.go:58 msg="Service started in: 85.428935ms"

$ sudo journalctl -n 100 | grep post-refresh
systemd[1]: Started snap.edgexfoundry.hook.post-refresh.0409b2f7-0d0b-42dd-97e5-e865eaf1dece.scope.
edgexfoundry.post-refresh[394831]: Refreshing from  (3722) to 2.3.0-dev.46 (3912)
...
edgexfoundry.post-refresh[394843]: Installing /snap/edgexfoundry/3912/config/core-metadata/res/uom.toml
systemd[1]: snap.edgexfoundry.hook.post-refresh.0409b2f7-0d0b-42dd-97e5-e865eaf1dece.scope: Deactivated successfully.

New Dependency Instructions (If applicable)

[codecov-commenter]

Codecov Report

Merging #4125 (8b19799) into main (166620d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #4125   +/-   ##
=======================================
  Coverage   43.61%   43.61%           
=======================================
  Files         120      120           
  Lines       10630    10630           
=======================================
  Hits         4636     4636           
  Misses       5607     5607           
  Partials      387      387           

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
5.1% Duplication

[MonicaisHer]

@farshidtz Thank you, looks good!

[farshidtz]

@cloudxxx8 could you please approve this? It's been reviewed.