3 files changed, 152 insertions, 0 deletions
diff --git a/src/orchestrator/go.sum b/src/orchestrator/go.sum
index dcda41d4..732bc280 100644
--- a/src/orchestrator/go.sum
+++ b/src/orchestrator/go.sum
@@ -201,6 +201,7 @@ github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFR
 github.com/rubenv/sql-migrate v0.0.0-20190902133344-8926f37f0bc1/go.mod h1:WS0rl9eEliYI8DPnr3TOwz4439pay+qNgzJoVya/DmY=
 github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=
+github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/soheilhy/cmux v0.1.4/go.mod h1:IM3LyeVVIOuxMH7sFAkER9+bJ4dT7Ms6E4xg4kGIyLM=
 github.com/spf13/afero v1.1.2/go.mod h1:j4pytiNVoe2o6bmDsKpLACNPDBIoEAkihy7loJ1B0CQ=
diff --git a/src/orchestrator/internal/db/README.md b/src/orchestrator/internal/db/README.md
new file mode 100644
index 00000000..cba1b7ea
--- /dev/null
+++ b/src/orchestrator/internal/db/README.md
@@ -0,0 +1,123 @@
+# Database Abstraction Layer
+
+This package contains implementations of the Database interface defined in `store.go`
+Any database can be used as the backend as long as the following interface is implemented;
+
+```go
+type Store interface {
+	// Returns nil if db health is good
+	HealthCheck() error
+
+	// Unmarshal implements any unmarshaling needed for the database
+	Unmarshal(inp []byte, out interface{}) error
+
+	// Creates a new master table with key and links data with tag and
+	// creates a pointer to the newly added data in the master table
+	Create(table string, key Key, tag string, data interface{}) error
+
+	// Reads data for a particular key with specific tag.
+	Read(table string, key Key, tag string) ([]byte, error)
+
+	// Update data for particular key with specific tag
+	Update(table string, key Key, tag string, data interface{}) error
+
+	// Deletes a specific tag data for key.
+	// TODO: If tag is empty, it will delete all tags under key.
+	Delete(table string, key Key, tag string) error
+
+	// Reads all master tables and data from the specified tag in table
+	ReadAll(table string, tag string) (map[string][]byte, error)
+}
+```
+
+Therefore, `mongo.go`, `consul.go` implement the above interface and can be used as the backend as needed based on initial configuration.
+
+## Details on Mongo Implementation
+
+`mongo.go` implements the above interface using the `go.mongodb.org/mongo-driver` package.
+The code converts incoming binary data and creates a new document in the database.
+
+### Create
+
+Arguments:
+```go
+collection string
+key interface
+tag string
+data []byte
+```
+
+Create inserts the provided `data` into the `collection` which returns an auto-generated (by `mongodb`) ID which we then associate with the `key` that is provided as one of the arguments.
+
+We use the `FindOneAndUpdate` mongo API to achieve this with the `upsert` option set to `true`.
+We create the following documents in mongodb for each new definition added to the database:
+
+There is a Master Key document that contains references to other documents which are related to this `key`.
+
+#### Master Key Entry
+```json
+{
+    "_id" : ObjectId("5e0a8554b78a15f71d2dce7e"),
+    "key" : { "rbname" : "edgex", "rbversion" : "v1"},
+    "defmetadata" : ObjectId("5e0a8554be261ecb57f067eb"),
+    "defcontent" : ObjectId("5e0a8377bcfcdd0f01dc7b0d")
+}
+```
+#### Metadata Key Entry
+```json
+{
+    "_id" : ObjectId("5e0a8554be261ecb57f067eb"),
+    "defmetadata" : { "rbname" : "edgex", "rbversion" : "v1", "chartname" : "", "description" : "", "labels" : null }
+}
+```
+#### Definition Content
+```json
+{
+    "_id" : ObjectId("5e0a8377bcfcdd0f01dc7b0d"),
+    "defcontent" : "H4sICCVd3FwAA3Byb2ZpbGUxLnRhcgDt1NEKgjAUxvFd7ylG98aWOsGXiYELxLRwJvj2rbyoIPDGiuD/uzmwM9iB7Vvruvrgw7CdXHsUn6Ejm2W3aopcP9eZLYRJM1voPN+ZndAm16kVSn9onheXMLheKeGqfdM0rq07/3bfUv9PJUkiR9+H+tSVajRymM6+lEqN7njxoVSbU+z2deX388r9nWzkr8fGSt5d79pnLOZfm0f+dRrzb7P4DZD/LyDJAAAAAAAAAAAAAAAA/+0Ksq1N5QAoAAA="
+}
+```
+
+### Unmarshal
+
+Data in mongo is stored as `bson` which is a compressed form of `json`. We need mongo to convert the stored `bson` data to regular `json`
+that we can use in our code when returned.
+
+We just use the `bson.Unmarshal` API to achieve this.
+
+### Read
+
+Arguments:
+```go
+collection string
+key interface
+tag string
+```
+
+Read is straight forward and it uses the `FindOne` API to find our Mongo document based on the provided `key` and then gets the corresponding data for the given `tag`. It will return []byte which can then be passed to the `Unmarshal` function to get the desired GO object.
+
+### Delete
+
+Delete is similar to Read and deletes all the objectIDs being stored for a given `key` in the collection.
+
+## Testing Interfaces
+
+The following interface exists to allow for the development of unit tests which don't require mongo to be running.
+It is mentioned so in the code as well.
+
+```go
+// MongoCollection defines the a subset of MongoDB operations
+// Note: This interface is defined mainly for mock testing
+type MongoCollection interface {
+	InsertOne(ctx context.Context, document interface{},
+		opts ...*options.InsertOneOptions) (*mongo.InsertOneResult, error)
+	FindOne(ctx context.Context, filter interface{},
+		opts ...*options.FindOneOptions) *mongo.SingleResult
+	FindOneAndUpdate(ctx context.Context, filter interface{},
+		update interface{}, opts ...*options.FindOneAndUpdateOptions) *mongo.SingleResult
+	DeleteOne(ctx context.Context, filter interface{},
+		opts ...*options.DeleteOptions) (*mongo.DeleteResult, error)
+	Find(ctx context.Context, filter interface{},
+		opts ...*options.FindOptions) (*mongo.Cursor, error)
+}
+```
+\ No newline at end of file
diff --git a/src/orchestrator/internal/logutils/logger.go b/src/orchestrator/internal/logutils/logger.go
new file mode 100644
index 00000000..2e8f9969
--- /dev/null
+++ b/src/orchestrator/internal/logutils/logger.go
@@ -0,0 +1,28 @@
+package logutils
+
+import (
+	log "github.com/sirupsen/logrus"
+)
+
+//Fields is type that will be used by the calling function
+type Fields map[string]interface{}
+
+func init() {
+	// Log as JSON instead of the default ASCII formatter.
+	log.SetFormatter(&log.JSONFormatter{})
+}
+
+// Error uses the fields provided and logs
+func Error(msg string, fields Fields) {
+	log.WithFields(log.Fields(fields)).Error(msg)
+}
+
+// Warn uses the fields provided and logs
+func Warn(msg string, fields Fields) {
+	log.WithFields(log.Fields(fields)).Warn(msg)
+}
+
+// Info uses the fields provided and logs
+func Info(msg string, fields Fields) {
+	log.WithFields(log.Fields(fields)).Info(msg)
+}