Plugins: Refactor Plugin Management (#40477)

* add core plugin flow

* add instrumentation

* move func

* remove cruft

* support external backend plugins

* refactor + clean up

* remove comments

* refactor loader

* simplify core plugin path arg

* cleanup loggers

* move signature validator to plugins package

* fix sig packaging

* cleanup plugin model

* remove unnecessary plugin field

* add start+stop for pm

* fix failures

* add decommissioned state

* export fields just to get things flowing

* fix comments

* set static routes

* make image loading idempotent

* merge with backend plugin manager

* re-use funcs

* reorder imports + remove unnecessary interface

* add some TODOs + remove unused func

* remove unused instrumentation func

* simplify client usage

* remove import alias

* re-use backendplugin.Plugin interface

* re order funcs

* improve var name

* fix log statements

* refactor data model

* add logic for dupe check during loading

* cleanup state setting

* refactor loader

* cleanup manager interface

* add rendering flow

* refactor loading + init

* add renderer support

* fix renderer plugin

* reformat imports

* track errors

* fix plugin signature inheritance

* name param in interface

* update func comment

* fix func arg name

* introduce class concept

* remove func

* fix external plugin check

* apply changes from pm-experiment

* fix core plugins

* fix imports

* rename interface

* comment API interface

* add support for testdata plugin

* enable alerting + use correct core plugin contracts

* slim manager API

* fix param name

* fix filter

* support static routes

* fix rendering

* tidy rendering

* get tests compiling

* fix install+uninstall

* start finder test

* add finder test coverage

* start loader tests

* add test for core plugins

* load core + bundled test

* add test for nested plugin loading

* add test files

* clean interface + fix registering some core plugins

* refactoring

* reformat and create sub packages

* simplify core plugin init

* fix ctx cancel scenario

* migrate initializer

* remove Init() funcs

* add test starter

* new logger

* flesh out initializer tests

* refactoring

* remove unused svc

* refactor rendering flow

* fixup loader tests

* add enabled helper func

* fix logger name

* fix data fetchers

* fix case where plugin dir doesn't exist

* improve coverage + move dupe checking to loader

* remove noisy debug logs

* register core plugins automagically

* add support for renderer in catalog

* make private func + fix req validation

* use interface

* re-add check for renderer in catalog

* tidy up from moving to auto reg core plugins

* core plugin registrar

* guards

* copy over core plugins for test infra

* all tests green

* renames

* propagate new interfaces

* kill old manager

* get compiling

* tidy up

* update naming

* refactor manager test + cleanup

* add more cases to finder test

* migrate validator to field

* more coverage

* refactor dupe checking

* add test for plugin class

* add coverage for initializer

* split out rendering

* move

* fixup tests

* fix uss test

* fix frontend settings

* fix grafanads test

* add check when checking sig errors

* fix enabled map

* fixup

* allow manual setup of CM

* rename to cloud-monitoring

* remove TODO

* add installer interface for testing

* loader interface returns

* tests passing

* refactor + add more coverage

* support 'stackdriver'

* fix frontend settings loading

* improve naming based on package name

* small tidy

* refactor test

* fix renderer start

* make cloud-monitoring plugin ID clearer

* add plugin update test

* add integration tests

* don't break all if sig can't be calculated

* add root URL check test

* add more signature verification tests

* update DTO name

* update enabled plugins comment

* update comments

* fix linter

* revert fe naming change

* fix errors endpoint

* reset error code field name

* re-order test to help verify

* assert -> require

* pm check

* add missing entry + re-order

* re-check

* dump icon log

* verify manager contents first

* reformat

* apply PR feedback

* apply style changes

* fix one vs all loading err

* improve log output

* only start when no signature error

* move log

* rework plugin update check

* fix test

* fix multi loading from cfg.PluginSettings

* improve log output #2

* add error abstraction to capture errors without registering a plugin

* add debug log

* add unsigned warning

* e2e test attempt

* fix logger

* set home path

* prevent panic

* alternate

* ugh.. fix home path

* return renderer even if not started

* make renderer plugin managed

* add fallback renderer icon, update renderer badge + prevent changes when renderer is installed

* fix icon loading

* rollback renderer changes

* use correct field

* remove unneccessary block

* remove newline

* remove unused func

* fix bundled plugins base + module fields

* remove unused field since refactor

* add authorizer abstraction

* loader only returns plugins expected to run

* fix multi log output

pkg/plugins/manager/testdata/nested-plugins/parent/MANIFEST.txt

@@ -0,0 +1,28 @@
+
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA512
+
+{
+  "manifestVersion": "2.0.0",
+  "signatureType": "grafana",
+  "signedByOrg": "grafana",
+  "signedByOrgName": "Grafana Labs",
+  "plugin": "test-ds",
+  "version": "1.0.0",
+  "time": 1629461930434,
+  "keyId": "7e4d0c6a708866e7",
+  "files": {
+    "plugin.json": "64e98031f30cfada473e0ad4b989ac10cd0c86844aab8c0d3fc36d8a9537a0b8",
+    "nested/plugin.json": "e64abd35cd211e0e4682974ad5cdd1be7a0b7cd24951d302a16d9e2cb6cefea4"
+  }
+}
+-----BEGIN PGP SIGNATURE-----
+Version: OpenPGP.js v4.10.1
+Comment: https://openpgpjs.org
+
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pkg/plugins/manager/testdata/nested-plugins/parent/nested/plugin.json

@@ -0,0 +1,14 @@
+{
+  "type": "panel",
+  "name": "Child",
+  "id": "test-panel",
+  "info": {
+    "description": "Child plugin",
+    "author": {
+      "name": "Grafana Labs",
+      "url": "http://grafana.com"
+    },
+    "version": "1.0.1",
+    "updated": "2020-10-30"
+  }
+}

pkg/plugins/manager/testdata/nested-plugins/parent/plugin.json

@@ -0,0 +1,15 @@
+{
+  "type": "datasource",
+  "name": "Parent",
+  "id": "test-ds",
+  "backend": true,
+  "info": {
+    "description": "Parent plugin",
+    "author": {
+      "name": "Grafana Labs",
+      "url": "http://grafana.com"
+    },
+    "version": "1.0.0",
+    "updated": "2020-10-20"
+  }
+}