Add initial REVIEW.md

Created REVIEW.md file that contains guidelines for commiters and
reviewers.

Change-Id: I89f19a148d61a30fec2e61335b4c91288269fbb3
Closes-Bug: #1791651

REVIEW.md

@@ -0,0 +1,155 @@
+# Code review guidelines
+
+This file contains guidelines for commiters and code reviewers.
+It is open for updates.
+
+## References
+
+Code should be compliant with rules from:
+- [Effective Go](https://golang.org/doc/effective_go.html)
+- [Code review comments](https://github.com/golang/go/wiki/CodeReviewComments)
+
+## Extra rules
+
+### Organizing imports
+
+Imports should be split into 3 groups:
+1.  standard library packages, e.g. `net/http`;
+2.  third-party library packages, e.g. `github.com/pkg/errors`;
+3.  packages under `github.com/Juniper/contrail`,
+    e.g. `github.com/Juniper/contrail/pkg/models`
+    and `github.com/Juniper/contrail/extension/pkg/models`;
+
+Additionally, each of the groups should be sorted alphabetically -
+`goimports` will do it for you.
+
+```diff
+-// Don't
+-import (
+-	"fmt"
+-
+-	"net/http"
+-
+-	"github.com/Juniper/contrail/pkg/models/basemodels"
+-	"github.com/labstack/echo"
+-)
++// Do
++import (
++	"fmt"
++	"net/http"
++
++	"github.com/labstack/echo"
++
++	"github.com/Juniper/contrail/pkg/models/basemodels"
++)
+```
+
+### Function signature formatting
+
+Function signatures that are too long (120 chars) should be split.
+Below is a list of possible formattings:
+1.  Single line - if everything fits in 120 chars
+
+    ```go
+func numericProtocolForEthertype(protocol, ethertype string) (numericProtocol string, err error) {
+	// ...
+}
+    ```
+
+2.  Multiline short - if function name with arguments is too long, but arguments
+    alone aren't longer than 120 chars.
+
+    ```go
+func decodeRowData(
+	relation pgoutput.Relation, row []pgoutput.Tuple,
+) (pk string, err error) {
+    ```
+
+3. Multiline long - if input or output arguments (or both) are longer than 120 chars.
+
+    ```go
+func decodeRowData(
+	relation pgoutput.Relation,
+	row []pgoutput.Tuple,
+) (pk string, data map[string]interface{}, err error) {
+    ```
+
+    or even
+
+    ```go
+func decodeRowData(
+	relation pgoutput.Relation,
+	row []pgoutput.Tuple,
+) (
+	pk string,
+	data map[string]interface{},
+	err error,
+) {
+    ```
+
+## Common mistakes
+
+### Named Result Parameters
+
+Result parameters can be named for documentational purposes.
+However, "bare returns" (returns that don't reference the variables
+that are returned) are discouraged.
+
+```diff
+-// Don't
+-func parseRouteTarget(rtName string) (ip net.IP, asn int, target int, err error) {
+-	// ...
+-	return
+-}
++// Do
++func parseRouteTarget(rtName string) (ip net.IP, asn int, target int, err error) {
++	// ...
++	return ip, asn, target, err
++}
+```
+
+See: [CRC: Named Result Parameters](https://github.com/golang/go/wiki/CodeReviewComments#named-result-parameters)
+
+### Package and type names
+
+New package names should be in singular form with a short word or abbreviation
+describing package contents. Names like `common` or `util` are discouraged.
+
+The package name shouldn't be repeated in type/variable/interface name,
+because client packages would reference the package name twice.
+
+```diff
+-// Don't
+-package types
+-
+-type TypesService {
+-	// ...
+-}
++// Do
++package types
++
++type Service {
++	// ...
++}
+```
+
+See: [CRC: Package Names](https://github.com/golang/go/wiki/CodeReviewComments#package-names)
+
+## Templates
+
+### Template file indentation
+
+New template files should be indented in the same way
+as the language they generate.
+In particular, Go template files should be indented with tabs.
+
+```diff
+-// Don't
+-type WriteService interface {
+-{% for schema in schemas %}{% if schema.Type != "abstract" and schema.ID %}
+-    Create{{ schema.JSONSchema.GoName }}(context.Context, *Create{{ schema.JSONSchema.GoName }}Request) (*Create{{ schema.JSONSchema.GoName }}Response, error)
++// Do
++type WriteService interface {
++{% for schema in schemas %}{% if schema.Type != "abstract" and schema.ID %}
++	Create{{ schema.JSONSchema.GoName }}(context.Context, *Create{{ schema.JSONSchema.GoName }}Request) (*Create{{ schema.JSONSchema.GoName }}Response, error)
+```