[confmap] Support expansion for environment variables with time forma…

…ts (#11241)

#### Description

This addresses
#10659.
In #10800
we removed restrictions on the types that can be allowed if expanded but
in our case, this still fails because of the checks existing in
`provider.checkRawConfType()`

This adds `time.Time` as a type in the `provider.checkRawConfType()`
instead of removing it completely.

#### Link to tracking issue
Fixes
#10659

<!--Describe what testing was performed and which tests were added.-->
#### Testing
- added a test case to handle time formats in provider.go and expand.go
- added an e2e test case to handle time formats

.chloggen/support-time-envvar-expansion.yaml

@@ -0,0 +1,26 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: confmap
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Allow using any YAML structure as a string when loading configuration including time.Time formats
+
+# One or more tracking issues or pull requests related to the change
+issues: [10659]
+
+# (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: |
+   Previously, fields with time.Time formats could not be used as strings in configurations
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

confmap/expand_test.go

@@ -185,6 +185,11 @@ func TestResolverExpandStringValues(t *testing.T) {
 			input:  "test_${env:BOOL}",
 			output: "test_true",
 		},
+		{
+			name:   "Timestamp",
+			input:  "test_${env:TIMESTAMP}",
+			output: "test_2023-03-20T03:17:55.432328Z",
+		},
 		{
 			name:   "MultipleSameMatches",
 			input:  "test_${env:BOOL}_test_${env:BOOL}",
@@ -414,6 +419,8 @@ func newEnvProvider() ProviderFactory {
 			return NewRetrievedFromYAML([]byte("[localhost:3042]"))
 		case "env:HOST":
 			return NewRetrievedFromYAML([]byte("localhost"))
+		case "env:TIMESTAMP":
+			return NewRetrievedFromYAML([]byte("2023-03-20T03:17:55.432328Z"))
 		case "env:OS":
 			return NewRetrievedFromYAML([]byte("ubuntu"))
 		case "env:PR":

confmap/internal/e2e/types_test.go

@@ -197,6 +197,16 @@ func TestStrictTypeCasting(t *testing.T) {
 			targetField: TargetFieldInlineString,
 			expected:    "inline field with 2006-01-02T15:04:05Z07:00 expansion",
 		},
+		{
+			value:       "2023-03-20T03:17:55.432328Z",
+			targetField: TargetFieldString,
+			expected:    "2023-03-20T03:17:55.432328Z",
+		},
+		{
+			value:       "2023-03-20T03:17:55.432328Z",
+			targetField: TargetFieldInlineString,
+			expected:    "inline field with 2023-03-20T03:17:55.432328Z expansion",
+		},
 		// issue 10787
 		{
 			value:       "true # comment with a ${env:hello.world} reference",

confmap/provider.go

@@ -6,6 +6,7 @@ package confmap // import "go.opentelemetry.io/collector/confmap"
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"go.uber.org/zap"
 	"gopkg.in/yaml.v3"
@@ -235,7 +236,7 @@ func checkRawConfType(rawConf any) error {
 		return nil
 	}
 	switch rawConf.(type) {
-	case int, int32, int64, float32, float64, bool, string, []any, map[string]any:
+	case int, int32, int64, float32, float64, bool, string, []any, map[string]any, time.Time:
 		return nil
 	default:
 		return fmt.Errorf(

confmap/provider_test.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"errors"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -103,6 +104,10 @@ func TestNewRetrievedFromYAMLString(t *testing.T) {
 			yaml:  "123",
 			value: 123,
 		},
+		{
+			yaml:  "2023-03-20T03:17:55.432328Z",
+			value: time.Date(2023, 3, 20, 3, 17, 55, 432328000, time.UTC),
+		},
 		{
 			yaml:  "true",
 			value: true,