adding datadog integration

Author: mashraf-222

env.example

@@ -13,15 +13,20 @@ OTEL_SERVICE_NAME=optimize-me
 OTEL_SERVICE_VERSION=0.1.0
 
 # Exporter Configuration
-# Type of exporter: "console" (development), "otlp" (production), or "jaeger"
-# (default: "console")
+# Type of exporter: "console" (development), "otlp" (production), "datadog", or "jaeger"
+# (default: "console", or "datadog" if DD_API_KEY is set)
 OTEL_EXPORTER_TYPE=console
 
 # OTLP Exporter Endpoint
 # Endpoint for OTLP exporter (used when OTEL_EXPORTER_TYPE is "otlp" or "jaeger")
 # Format: http://host:port (default: "http://localhost:4318")
 OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
 
+# OTLP Traces Exporter (for opentelemetry-instrument)
+# Used by opentelemetry-instrument command: "console" or "otlp"
+# (default: not set, uses OTEL_EXPORTER_TYPE)
+OTEL_TRACES_EXPORTER=console
+
 # Sampling Rate
 # Sampling rate for traces (0.0 to 1.0)
 # 1.0 = 100% sampling (all traces), 0.1 = 10% sampling (default: 1.0)
@@ -31,3 +36,34 @@ OTEL_TRACES_SAMPLER_ARG=1.0
 # Logging level for OpenTelemetry (DEBUG, INFO, WARNING, ERROR)
 # (default: "INFO")
 OTEL_LOG_LEVEL=INFO
+
+# Datadog Configuration (optional)
+# These are used when OTEL_EXPORTER_TYPE is "datadog" or when DD_API_KEY is set
+# Required for Datadog exporter and Docker Compose
+# 
+# How to get your API key:
+# 1. Sign in to Datadog: https://app.datadoghq.com (or create a free account)
+# 2. Go to: Organization Settings → API Keys
+#    Direct link: https://app.datadoghq.com/organization-settings/api-keys
+# 3. Click "New Key" or "Create Key"
+# 4. Give it a name and copy the key (you'll only see it once!)
+# 5. Set it here or export as: export DD_API_KEY=your-key
+DD_API_KEY=
+
+# Datadog Site (default: "datadoghq.com")
+# Options: datadoghq.com, datadoghq.eu, us3.datadoghq.com, etc.
+DD_SITE=datadoghq.com
+
+# Datadog Environment (default: "development")
+DD_ENV=development
+
+# Datadog Service Name (optional, defaults to OTEL_SERVICE_NAME)
+DD_SERVICE=optimize-me
+
+# Datadog Service Version (optional, defaults to OTEL_SERVICE_VERSION)
+DD_VERSION=0.1.0
+
+# Datadog Agent URL (optional, for native Datadog protocol)
+# When using Docker Compose, this is automatically http://localhost:8126
+# When using OTLP (recommended), use http://localhost:4317
+DD_AGENT_URL=http://localhost:8126