[OTAGENT-412] Updated modules adding ability for serialize exporter to set proxy variables (open-telemetry#41041)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
This PR improves the serializer exporter by introducing support for HTTP
proxy settings via both environment variables and explicit
configuration.

- The exporter now reads from the standard environment variables:
HTTP_PROXY, HTTPS_PROXY, and NO_PROXY.
- A new proxy_url field was added to the exporter's configuration. If
set, this will override the environment variables.

<!--Describe what testing was performed and which tests were added.-->
#### Testing
Added new unit tests and manually tested with proxy applciation.

#### Related PR
DataDog/datadog-agent#38224

---------

Co-authored-by: Yang Song <songy23@users.noreply.github.com>

Author: 2 people

.chloggen/tim.liakh-serializer-exporter-ignoring-proxy-fix.yaml

@@ -0,0 +1,22 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: datadogexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added ability for Datadog metrics serializer exporter to set proxy variables
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [41041]
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# 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: [user]

connector/datadogconnector/go.mod

@@ -60,7 +60,7 @@ require (
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline/logsagentpipelineimpl v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/logsagentexporter v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
-	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.68.0-devel.0.20250604170009-feaecfbfd700 // indirect
+	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.69.0-devel.0.20250630223051-02255cc64e1f // indirect
 	github.com/DataDog/datadog-agent/comp/serializer/logscompression v0.67.0 // indirect
 	github.com/DataDog/datadog-agent/comp/serializer/metricscompression v0.67.0 // indirect
 	github.com/DataDog/datadog-agent/comp/trace/compression/def v0.67.0 // indirect
@@ -134,7 +134,7 @@ require (
 	github.com/DataDog/opentelemetry-mapping-go/pkg/otlp/logs v0.29.0 // indirect
 	github.com/DataDog/opentelemetry-mapping-go/pkg/quantile v0.29.0 // indirect
 	github.com/DataDog/sketches-go v1.4.7 // indirect
-	github.com/DataDog/viper v1.14.0 // indirect
+	github.com/DataDog/viper v1.14.1-0.20250612143030-1b15c8822ed4 // indirect
 	github.com/DataDog/zstd v1.5.6 // indirect
 	github.com/DataDog/zstd_0 v0.0.0-20210310093942-586c1286621f // indirect
 	github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.27.0 // indirect
@@ -254,7 +254,7 @@ require (
 	github.com/shirou/gopsutil/v4 v4.25.6 // indirect
 	github.com/shoenig/go-m1cpu v0.1.6 // indirect
 	github.com/spf13/afero v1.14.0 // indirect
-	github.com/spf13/cast v1.8.0 // indirect
+	github.com/spf13/cast v1.9.2 // indirect
 	github.com/spf13/cobra v1.9.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
@@ -344,7 +344,7 @@ require (
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.39.0 // indirect
-	golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 // indirect
+	golang.org/x/exp v0.0.0-20250606033433-dcc06ee1d476 // indirect
 	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect
 	golang.org/x/sync v0.15.0 // indirect

connector/datadogconnector/go.sum

@@ -9,7 +9,7 @@ require (
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline v0.67.0-devel.0.20250507144401-a64863d1e01a
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline/logsagentpipelineimpl v0.67.0-devel.0.20250507144401-a64863d1e01a
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/logsagentexporter v0.67.0-devel.0.20250507144401-a64863d1e01a
-	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.68.0-devel.0.20250604170009-feaecfbfd700
+	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.69.0-devel.0.20250630223051-02255cc64e1f
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/metricsclient v0.67.0
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/testutil v0.67.0
 	github.com/DataDog/datadog-agent/comp/serializer/logscompression v0.67.0
@@ -158,7 +158,7 @@ require (
 	github.com/DataDog/mmh3 v0.0.0-20210722141835-012dc69a9e49 // indirect
 	github.com/DataDog/opentelemetry-mapping-go/pkg/otlp/logs v0.29.0 // indirect
 	github.com/DataDog/sketches-go v1.4.7 // indirect
-	github.com/DataDog/viper v1.14.0 // indirect
+	github.com/DataDog/viper v1.14.1-0.20250612143030-1b15c8822ed4 // indirect
 	github.com/DataDog/zstd v1.5.6 // indirect
 	github.com/DataDog/zstd_0 v0.0.0-20210310093942-586c1286621f // indirect
 	github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.27.0 // indirect
@@ -370,7 +370,7 @@ require (
 	github.com/shoenig/go-m1cpu v0.1.6 // indirect
 	github.com/shurcooL/httpfs v0.0.0-20230704072500-f1e31cf0ba5c // indirect
 	github.com/spf13/afero v1.14.0 // indirect
-	github.com/spf13/cast v1.8.0 // indirect
+	github.com/spf13/cast v1.9.2 // indirect
 	github.com/spf13/cobra v1.9.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
@@ -470,7 +470,7 @@ require (
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.39.0 // indirect
-	golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 // indirect
+	golang.org/x/exp v0.0.0-20250606033433-dcc06ee1d476 // indirect
 	golang.org/x/mod v0.25.0 // indirect
 	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect

exporter/datadogexporter/go.mod

@@ -57,7 +57,7 @@ require (
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/logsagentpipeline/logsagentpipelineimpl v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/logsagentexporter v0.67.0-devel.0.20250507144401-a64863d1e01a // indirect
-	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.68.0-devel.0.20250604170009-feaecfbfd700 // indirect
+	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/exporter/serializerexporter v0.69.0-devel.0.20250630223051-02255cc64e1f // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/metricsclient v0.67.0 // indirect
 	github.com/DataDog/datadog-agent/comp/otelcol/otlp/components/statsprocessor v0.67.0 // indirect
 	github.com/DataDog/datadog-agent/comp/serializer/logscompression v0.67.0 // indirect
@@ -138,7 +138,7 @@ require (
 	github.com/DataDog/opentelemetry-mapping-go/pkg/otlp/metrics v0.29.0 // indirect
 	github.com/DataDog/opentelemetry-mapping-go/pkg/quantile v0.29.0 // indirect
 	github.com/DataDog/sketches-go v1.4.7 // indirect
-	github.com/DataDog/viper v1.14.0 // indirect
+	github.com/DataDog/viper v1.14.1-0.20250612143030-1b15c8822ed4 // indirect
 	github.com/DataDog/zstd v1.5.6 // indirect
 	github.com/DataDog/zstd_0 v0.0.0-20210310093942-586c1286621f // indirect
 	github.com/GoogleCloudPlatform/opentelemetry-operations-go/detectors/gcp v1.27.0 // indirect
@@ -263,7 +263,7 @@ require (
 	github.com/shirou/gopsutil/v4 v4.25.6 // indirect
 	github.com/shoenig/go-m1cpu v0.1.6 // indirect
 	github.com/spf13/afero v1.14.0 // indirect
-	github.com/spf13/cast v1.8.0 // indirect
+	github.com/spf13/cast v1.9.2 // indirect
 	github.com/spf13/cobra v1.9.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
@@ -357,7 +357,7 @@ require (
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/crypto v0.39.0 // indirect
-	golang.org/x/exp v0.0.0-20250408133849-7e4ce0ab07d0 // indirect
+	golang.org/x/exp v0.0.0-20250606033433-dcc06ee1d476 // indirect
 	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect
 	golang.org/x/sync v0.15.0 // indirect