Add comments and unittests to go-sqlcommenter-core (#218)

Author: sjs994

go/core/core.go

@@ -22,20 +22,23 @@ import (
 	"runtime"
 	"sort"
 	"strings"
-
-	"go.opentelemetry.io/otel/propagation"
 )
 
+// Constants used as key string for tags.
+// It is not necessary that all SQLCommenter frameworks/ORMs will contain all these keys i.e.
+// it is on best-effort basis.
 const (
 	Route       string = "route"
-	Controller  string = "controller"
-	Action      string = "action"
-	Framework   string = "framework"
-	Driver      string = "db_driver"
-	Traceparent string = "traceparent"
-	Application string = "application"
+	Controller         = "controller"
+	Action             = "action"
+	Framework          = "framework"
+	Driver             = "db_driver"
+	Traceparent        = "traceparent"
+	Application        = "application"
 )
 
+// CommenterConfig contains configurations for SQLCommenter library.
+// We can enable and disable certain tags by enabling these configurations.
 type CommenterConfig struct {
 	EnableDBDriver    bool
 	EnableRoute       bool
@@ -46,11 +49,15 @@ type CommenterConfig struct {
 	EnableApplication bool
 }
 
+// StaticTags are few tags that can be set by the application and will be constant
+// for every API call.
 type StaticTags struct {
 	Application string
 	DriverName  string
 }
 
+// CommenterOptions contains all options regarding SQLCommenter library.
+// This includes the configurations as well as any static tags.
 type CommenterOptions struct {
 	Config CommenterConfig
 	Tags   StaticTags
@@ -60,13 +67,19 @@ func encodeURL(k string) string {
 	return url.QueryEscape(k)
 }
 
-func GetFunctionName(i interface{}) string {
+// GetFunctionName returns the name of the function passed.
+func GetFunctionName(i any) string {
 	if i == nil {
 		return ""
 	}
 	return runtime.FuncForPC(reflect.ValueOf(i).Pointer()).Name()
 }
 
+// ConvertMapToComment returns a comment string given a map of key-value pairs of tags.
+// There are few steps involved here:
+//   - Sorting the tags by key string
+//   - url encoding the key value pairs
+//   - Formatting the key value pairs as "key1=value1,key2=value2" format.
 func ConvertMapToComment(tags map[string]string) string {
 	var sb strings.Builder
 	i, sz := 0, len(tags)
@@ -89,6 +102,7 @@ func ConvertMapToComment(tags map[string]string) string {
 	return sb.String()
 }
 
+// ExtractTraceparent extracts the traceparent field using OpenTelemetry library.
 func ExtractTraceparent(ctx context.Context) propagation.MapCarrier {
 	// Serialize the context into carrier
 	textMapPropogator := propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{})
@@ -97,12 +111,15 @@ func ExtractTraceparent(ctx context.Context) propagation.MapCarrier {
 	return carrier
 }
 
+// RequestTagsProvider adds a basic interface for other libraries like gorilla/mux to implement.
 type RequestTagsProvider interface {
 	Route() string
 	Action() string
 	Framework() string
 }
 
+// ContextInject injects the tags key-value pairs into context,
+// which can be later passed into drivers/ORMs to finally inject them into SQL queries.
 func ContextInject(ctx context.Context, h RequestTagsProvider) context.Context {
 	ctx = context.WithValue(ctx, Route, h.Route())
 	ctx = context.WithValue(ctx, Action, h.Action())

go/core/core_test.go

@@ -0,0 +1,101 @@
+package core
+
+import (
+	"context"
+	"testing"
+)
+
+func TestConvertMapToComment(t *testing.T) {
+	for _, tc := range []struct {
+		desc   string
+		tagMap map[string]string
+		want   string
+	}{
+		{
+			desc: "nil tagMap",
+			want: "",
+		},
+		{
+			desc:   "no tags",
+			tagMap: map[string]string{},
+			want:   "",
+		},
+		{
+			desc: "only one tag",
+			tagMap: map[string]string{
+				Route: "test-route",
+			},
+			want: "route='test-route'",
+		},
+		{
+			desc: "only one tag with url encoding",
+			tagMap: map[string]string{
+				Route: "test/route",
+			},
+			want: "route='test%2Froute'",
+		},
+		{
+			desc: "multiple tags",
+			tagMap: map[string]string{
+				Route:  "test/route",
+				Action: "test-action",
+				Driver: "sql-pg",
+			},
+			want: "action='test-action',db_driver='sql-pg',route='test%2Froute'",
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			if got, want := ConvertMapToComment(tc.tagMap), tc.want; got != want {
+				t.Errorf("ConvertMapToComment(%+v) = %q, want = %q", tc.tagMap, got, want)
+			}
+		})
+	}
+}
+
+type testRequestProvider struct {
+	withRoute     string
+	withAction    string
+	withFramework string
+}
+
+func (p *testRequestProvider) Route() string     { return p.withRoute }
+func (p *testRequestProvider) Action() string    { return p.withAction }
+func (p *testRequestProvider) Framework() string { return p.withFramework }
+
+func TestContextInject(t *testing.T) {
+	tagsProvider := &testRequestProvider{
+		withRoute:     "test-route",
+		withAction:    "test-action",
+		withFramework: "test-framework",
+	}
+	ctx := context.Background()
+	gotCtx := ContextInject(ctx, tagsProvider)
+
+	for _, tc := range []struct {
+		desc string
+		key  string
+		want string
+	}{
+		{
+			desc: "fetch action",
+			key:  Action,
+			want: "test-action",
+		},
+		{
+			desc: "fetch route",
+			key:  Route,
+			want: "test-route",
+		},
+		{
+			desc: "fetch framework",
+			key:  Framework,
+			want: "test-framework",
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			if got, want := gotCtx.Value(tc.key), tc.want; got != want {
+				t.Errorf("ContextInject(ctx, tagsProvider) context.Value(%q) = %q, want = %q", tc.key, got, tc.want)
+			}
+		})
+	}
+}