feat(snap): use updated environment variable injection

[MonicaisHer]

For details on the new scheme for setting environment variables, please refer to edgexfoundry/edgex-go#3986.

Co-authored-by: Siggi Skulason [email protected]
Signed-off-by: Mengyi Wang [email protected]

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/device-mqtt-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?) N/A - they are in the imported module Add tests for snap config options canonical/edgex-snap-testing#53
• 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

1. set up:

snap install edgexfoundry --edge
snap install edgex-device-mqtt --channel="edge/pr-365"

2. Enable config and set a global config value:

$ snap set edgex-device-mqtt config-enabled=true
$ snap set edgex-device-mqtt config.service-startupmsg="testing injection"

$ snap start edgex-device-mqtt
Started.

$ snap logs -n=all edgex-device-mqtt | grep "testing injection"
2022-04-26T11:07:27+02:00 edgex-device-mqtt.device-mqtt[1750732]: ++ export 'SERVICE_STARTUPMSG=testing injection'
2022-04-26T11:07:27+02:00 edgex-device-mqtt.device-mqtt[1750732]: ++ SERVICE_STARTUPMSG='testing injection'
2022-04-26T11:07:28+02:00 edgex-device-mqtt.device-mqtt[1750732]: level=INFO ts=2022-04-26T09:07:28.360080301Z app=device-mqtt source=variables.go:352 msg="Variables override of 'Service.StartupMsg' by environment variable: SERVICE_STARTUPMSG=testing injection"

3. Set a app-specific value:

$ snap set edgex-device-mqtt apps.device-mqtt.config.service-port=11111

$ snap restart edgex-device-mqtt
Restarted.

$ snap logs -n=all edgex-device-mqtt | grep "11111"
msg="Web server starting (localhost:11111)"

New Dependency Instructions (If applicable)

[MonicaisHer]

@farshidtz Could you please review this? Thanks.

[codecov-commenter]

Codecov Report

Merging #365 (119d050) into main (4d191eb) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #365   +/-   ##
=======================================
  Coverage   21.34%   21.34%           
=======================================
  Files           5        5           
  Lines         492      492           
=======================================
  Hits          105      105           
  Misses        374      374           
  Partials       13       13           

---

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[MonicaisHer]

This PR will be ready for merge, once the new hook has been tagged and imported by this PR.

[farshidtz]

Please upgrade edgex-snap-hooks to beta.5 and go mod tidy.

[farshidtz]

Thanks. Works as expected:

$ snap install edgex-device-mqtt --channel="edge/pr-365"
edgex-device-mqtt (edge/pr-365) 2.2.0-dev.15 from Canonical✓ installed

# Verify error handling
$ snap set edgex-device-mqtt config.service-startupmsg="testing injection"
error: cannot perform the following tasks:
- Run configure hook of "edgex-device-mqtt" snap (run hook "configure": 
-----
edgex-device-mqtt.configure: could not process options: 'config.' and 'apps.' options are allowed only when config-enabled is true.

WARNING: Setting config-enabled=true will unset existing 'env.' options and ignore future sets!!
-----)

$ snap set edgex-device-mqtt config-enabled=true
$ snap set edgex-device-mqtt config.service.startupmsg="testing injection"
error: cannot perform the following tasks:
- Run configure hook of "edgex-device-mqtt" snap (run hook "configure": edgex-device-mqtt.configure: could not process options: error converting config key to environment variable key: config key must not contain dots: service.startupmsg)

# Test global config
$ snap set edgex-device-mqtt config.service-startupmsg="testing injection"
$ snap start edgex-device-mqtt
Started.
$ snap logs -n=all edgex-device-mqtt | grep "testing injection"
2022-04-26T11:42:18+02:00 edgex-device-mqtt.device-mqtt[54398]: ++ export 'SERVICE_STARTUPMSG=testing injection'
2022-04-26T11:42:18+02:00 edgex-device-mqtt.device-mqtt[54398]: ++ SERVICE_STARTUPMSG='testing injection'
2022-04-26T11:42:19+02:00 edgex-device-mqtt.device-mqtt[54398]: level=INFO ts=2022-04-26T09:42:19.024095794Z app=device-mqtt source=variables.go:352 msg="Variables override of 'Service.StartupMsg' by environment variable: SERVICE_STARTUPMSG=testing injection"

# test app-specific config
$ snap set edgex-device-mqtt apps.device-mqtt.config.service-port=11111
$ snap restart edgex-device-mqtt
Restarted.
$ snap logs -n=all edgex-device-mqtt | grep "11111"
2022-04-26T11:43:08+02:00 edgex-device-mqtt.device-mqtt[54629]: ++ export SERVICE_PORT=11111
2022-04-26T11:43:08+02:00 edgex-device-mqtt.device-mqtt[54629]: ++ SERVICE_PORT=11111
2022-04-26T11:43:08+02:00 edgex-device-mqtt.device-mqtt[54629]: level=INFO ts=2022-04-26T09:43:08.378704974Z app=device-mqtt source=variables.go:352 msg="Variables override of 'Service.Port' by environment variable: SERVICE_PORT=11111"

# check the env file
$ cat /var/snap/edgex-device-mqtt/current/config/device-mqtt/res/device-mqtt.env 
export SERVICE_STARTUPMSG="testing injection"
export SERVICE_PORT="11111"