redis storage backend (#1082)

* pkg/storage: add redis storage backend

* pkg/storage/redis: set record create time correctly

* pkg/storage/redis: add docs

* pkg/storage/redis: run test with redis tag only

* pkg/storage/redis: use localhost

* pkg/storage/redis: use 127.0.0.1

* pkg/storage/redis: honor REDIS_URL env

* .github/workflows: add missing config for redis service

* .github/workflows: map redis ports to host

* pkg/storage/redis: use proto marshaler instead of json one

* pkg/storage/redis: use better implementation

By using redis supported datastructure:

 - Hash for storing record
 - Sorted set for storing by version
 - Set for storing deleted ids

List operation will be now performed in O(log(N)+M) instead of O(N) like
previous implementation.

* pkg/storage/redis: add tx to wrap redis transaction

* pkg/storage/redis: set record type in New

* pkg/storage/redis: make sure tx commands appear in right order

* pkg/storage/redis: make deletePermanentAfter as argument

* pkg/storage/redis: make sure version is incremented when deleting

* pkg/storage/redis: fix linter

* pkg/storage/redis: fix cmd construction

.github/workflows/test.yaml

@@ -125,3 +125,27 @@ jobs:
 
       - name: test
         run: go test -v ./integration/...
+
+  storage-backend-test-redis:
+    runs-on: ubuntu-latest
+    services:
+      redis:
+        image: redis
+        options: >-
+          --health-cmd "redis-cli ping"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+        ports:
+          - 6379:6379
+    steps:
+      - name: install go
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.14.x
+
+      - name: checkout code
+        uses: actions/checkout@v2
+
+      - name: test
+        run: go test -v -tags redis ./pkg/storage/redis/...