Include milliseconds in DataDog timestamp format [Refs #152]

.chloggen/main.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component (e.g. pkg/quantile)
+component: pkg/otlp/logs
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: DataDog log timestamp (ie. '@timestamp') now includes milliseconds.
+
+# The PR related to this change
+issues: [#152]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

pkg/otlp/logs/logs_translator.go

@@ -19,7 +19,6 @@ import (
 	"encoding/hex"
 	"strconv"
 	"strings"
-	"time"
 
 	"github.com/DataDog/datadog-api-client-go/v2/api/datadog"
 	"github.com/DataDog/datadog-api-client-go/v2/api/datadogV2"
@@ -156,7 +155,7 @@ func Transform(lr plog.LogRecord, res pcommon.Resource, logger *zap.Logger) data
 	if lr.Timestamp() != 0 {
 		// we are retaining the nano second precision in this property
 		l.AdditionalProperties[otelTimestamp] = strconv.FormatInt(lr.Timestamp().AsTime().UnixNano(), 10)
-		l.AdditionalProperties[ddTimestamp] = lr.Timestamp().AsTime().Format(time.RFC3339)
+		l.AdditionalProperties[ddTimestamp] = lr.Timestamp().AsTime().Format("2006-01-02T15:04:05.000Z")
 	}
 	if l.Message == "" {
 		// set the Message to the Body in case it wasn't already parsed as part of the attributes

pkg/otlp/logs/logs_translator_test.go

@@ -410,6 +410,31 @@ func TestTransform(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "Timestamps are formatted properly",
+			args: args{
+				lr: func() plog.LogRecord {
+					l := plog.NewLogRecord()
+					l.SetTimestamp(pcommon.Timestamp(uint64(1700499303397000000)))
+					l.SetSeverityNumber(5)
+					return l
+				}(),
+				res: func() pcommon.Resource {
+					r := pcommon.NewResource()
+					return r
+				}(),
+			},
+			want: datadogV2.HTTPLogItem{
+				Ddtags:  datadog.PtrString(""),
+				Message: *datadog.PtrString(""),
+				AdditionalProperties: map[string]string{
+					"status":           "debug",
+					otelSeverityNumber: "5",
+					ddTimestamp:        "2023-11-20T16:55:03.397Z",
+					otelTimestamp:      "1700499303397000000",
+				},
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {