[exporter/datadog] Deprecate TagsConfig.GetHostTags method (open-telemetry#8975)

* [exporter/datadog] Deprecate GetHostTags method

* Also add `nolint` to silence all the linters

* Add CHANGELOG entry

Author: mx-psi

CHANGELOG.md

@@ -17,6 +17,7 @@
 
 - `datadogexporter`: Deprecate `service` setting in favor of `service.name` semantic convention (#8784)
 - `datadogexporter`: Deprecate `version` setting in favor of `service.version` semantic convention (#8784)
+- `datadogexporter`: Deprecate `GetHostTags` method from `TagsConfig` struct (#8975)
 
 ### 🚀 New components 🚀
 

exporter/datadogexporter/config/config.go

@@ -244,6 +244,7 @@ type TagsConfig struct {
 }
 
 // GetHostTags gets the host tags extracted from the configuration
+// Deprecated: [v0.49.0] Access fields explicitly instead.
 func (t *TagsConfig) GetHostTags() []string {
 	tags := t.Tags
 

exporter/datadogexporter/hostmetadata.go

@@ -15,15 +15,33 @@
 package datadogexporter // import "github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter"
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/config"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/internal/metadata"
 )
 
+// getHostTags gets the host tags extracted from the configuration.
+func getHostTags(t *config.TagsConfig) []string {
+	tags := t.Tags
+
+	if len(tags) == 0 {
+		//lint:ignore SA1019 Will be removed when environment variable detection is removed
+		tags = strings.Split(t.EnvVarTags, " ") //nolint
+	}
+
+	if t.Env != "none" {
+		tags = append(tags, fmt.Sprintf("env:%s", t.Env))
+	}
+	return tags
+}
+
 // newMetadataConfigfromConfig creates a new metadata pusher config from the main config.
 func newMetadataConfigfromConfig(cfg *config.Config) metadata.PusherConfig {
 	return metadata.PusherConfig{
 		ConfigHostname:      cfg.Hostname,
-		ConfigTags:          cfg.GetHostTags(),
+		ConfigTags:          getHostTags(&cfg.TagsConfig),
 		MetricsEndpoint:     cfg.Metrics.Endpoint,
 		APIKey:              cfg.API.Key,
 		UseResourceMetadata: cfg.UseResourceMetadata,

exporter/datadogexporter/hostmetadata_test.go

@@ -0,0 +1,80 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package datadogexporter // import "github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter"
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/config"
+)
+
+func TestHostTags(t *testing.T) {
+	tc := config.TagsConfig{
+		Hostname: "customhost",
+		Env:      "customenv",
+		// Service and version should be only used for traces
+		Service: "customservice",
+		Version: "customversion",
+		Tags:    []string{"key1:val1", "key2:val2"},
+	}
+
+	assert.ElementsMatch(t,
+		[]string{
+			"env:customenv",
+			"key1:val1",
+			"key2:val2",
+		},
+		getHostTags(&tc),
+	)
+
+	tc = config.TagsConfig{
+		Hostname: "customhost",
+		Env:      "customenv",
+		// Service and version should be only used for traces
+		Service:    "customservice",
+		Version:    "customversion",
+		Tags:       []string{"key1:val1", "key2:val2"},
+		EnvVarTags: "key3:val3 key4:val4",
+	}
+
+	assert.ElementsMatch(t,
+		[]string{
+			"env:customenv",
+			"key1:val1",
+			"key2:val2",
+		},
+		getHostTags(&tc),
+	)
+
+	tc = config.TagsConfig{
+		Hostname: "customhost",
+		Env:      "customenv",
+		// Service and version should be only used for traces
+		Service:    "customservice",
+		Version:    "customversion",
+		EnvVarTags: "key3:val3 key4:val4",
+	}
+
+	assert.ElementsMatch(t,
+		[]string{
+			"env:customenv",
+			"key3:val3",
+			"key4:val4",
+		},
+		getHostTags(&tc),
+	)
+}