Support reading package name from WSK_PACKAGE env var

[alexkli]

Moved from adobe/wskdebug#49

Motivation

Some Openwhisk applications deploy their actions in a package that is defined at deployment time and includes a version number etc. OTOH, when using a VS Code launch config one cannot easily use environment variables for the action name, so something like wskdebug $WSK_PACKAGE/myaction does NOT work inside a VS code launch.json args. It is impractical if each developer, working against a different package, has to modify the VS code launch.json which is usually version controlled.

Solution

Users would configure wskdebug myaction in their launch.json config. Upon start, wskdebug would:

• if WSK_PACKAGE env var is set: use $WSK_PACKAGE/myaction as fully qualified action name
• if WSK_PACKAGE is not set: use myaction

In case the cli argument already contains a package as part of the action name (package/myaction), the cli arg would be used and the env var ignored. This would follow standard cli behavior patterns.

Notes

Sometimes the action name might also get dynamically generated. So maybe we should also support WSK_ACTION as well? What to specify on the cli then?

Also update the README with updated vscode instructions:

• envFile for new WSK_PACKAGE
• envFile for WSK_CONFIG_FILE

[alexkli]

In #37 I added support for WSK_PACKAGE as described above. I did not add WSK_ACTION as that's a speculative feature right now.