sovdev-logger Configuration Guide

Environment-based configuration for all sovdev-logger implementations (TypeScript, Python, C#, PHP, Go, Rust).

Environment Variables

All sovdev-logger implementations use the same environment variables for consistent behavior across programming languages.

Service Identification

All sovdev-logger implementations require service identification using OpenTelemetry standard fields.

Required Parameters:

Parameter	Description	Required	Example
service_name	Your service identifier	Yes	company-lookup-service
service_version	Service version	No*	1.0.0
peer_services	External systems mapping	No	See below

* Auto-detected from package.json if not provided

Initialization (TypeScript/JavaScript)

import { sovdev_initialize, create_peer_services } from 'sovdev-logger';

// Define peer services (external systems you call)
const PEER_SERVICES = create_peer_services({
  BRREG: 'SYS1234567',        // External API system ID
  DATABASE: 'INT0001234',     // Internal database system ID
  // INTERNAL is auto-generated for internal operations
});

// Initialize logger
sovdev_initialize(
  'company-lookup-service',   // Required: your service name
  '1.0.0',                    // Optional: version (auto-detected from package.json)
  PEER_SERVICES.mappings      // Optional: peer service mappings
);

Initialization (Python)

# Python
from sovdev_logger import sovdev_initialize, create_peer_services

PEER_SERVICES = create_peer_services({
  'BRREG': 'SYS1234567',
  'DATABASE': 'INT0001234'
})

sovdev_initialize('company-lookup-service', '1.0.0', PEER_SERVICES['mappings'])

Initialization (Go)

// Go
import (
  "github.com/helpers-no/sovdev-logger/go/sovdevlogger"
)

peerServices := sovdevlogger.CreatePeerServices(map[string]string{
  "BRREG":    "SYS1234567",
  "DATABASE": "INT0001234",
})

sovdevlogger.SovdevInitialize("company-lookup-service", "1.0.0", peerServices.Mappings)

Initialization (C# - Planned)

// C#
using Sovdev.Logger;

var peerServices = SovdevLogger.CreatePeerServices(new Dictionary<string, string> {
  { "BRREG", "SYS1234567" },
  { "DATABASE", "INT0001234" }
});

SovdevLogger.Initialize("company-lookup-service", "1.0.0", peerServices.Mappings);

Peer Services Explained

Peer services track which external systems your service interacts with:

TypeScript Example:

import { sovdev_log, SOVDEV_LOGLEVELS } from 'sovdev-logger';

// When calling external API
sovdev_log(
  SOVDEV_LOGLEVELS.INFO,
  'lookupCompany',
  'Looking up company',
  PEER_SERVICES.BRREG,     // Tracks call to BRREG system
  { orgNr: '123456789' },
  null
);

// For internal operations
sovdev_log(
  SOVDEV_LOGLEVELS.INFO,
  'processData',
  'Processing batch',
  PEER_SERVICES.INTERNAL,  // Internal operation
  { count: 10 },
  null
);

Go Example:

import "github.com/helpers-no/sovdev-logger/go/sovdevlogger"

// When calling external API
sovdevlogger.SovdevLog(
  sovdevlogger.INFO,
  "lookupCompany",
  "Looking up company",
  peerServices.BRREG,      // Tracks call to BRREG system
  map[string]interface{}{"orgNr": "123456789"},
  nil,
  nil,
  "",
)

// For internal operations
sovdevlogger.SovdevLog(
  sovdevlogger.INFO,
  "processData",
  "Processing batch",
  peerServices.INTERNAL,   // Internal operation
  map[string]interface{}{"count": 10},
  nil,
  nil,
  "",
)

Python Example:

from sovdev_logger import sovdev_log, SOVDEV_LOGLEVELS

# When calling external API
sovdev_log(
  SOVDEV_LOGLEVELS.INFO,
  'lookupCompany',
  'Looking up company',
  PEER_SERVICES['BRREG'],  # Tracks call to BRREG system
  {'orgNr': '123456789'},
  None
)

# For internal operations
sovdev_log(
  SOVDEV_LOGLEVELS.INFO,
  'processData',
  'Processing batch',
  PEER_SERVICES['INTERNAL'],  # Internal operation
  {'count': 10},
  None
)

Log Output:

{
  "service_name": "company-lookup-service",
  "service_version": "1.0.0",
  "session_id": "18df09dd-c321-43d8-aa24-19dd7c149a56",
  "peer_service": "SYS1234567",
  "function_name": "lookupCompany",
  "message": "Looking up company",
  "trace_id": "3f43a369-9cc2-4351-a472-c5d050ab9cbf",
  "event_id": "29319322-17a6-40bc-8ea6-ac0fc9771177",
  "log_type": "transaction"
}

Logging Output Control

Variable	Values	Default	Description
LOG_TO_CONSOLE	true/false	Smart default*	Enable/disable console output
LOG_TO_FILE	true/false	true	Enable/disable file logging
LOG_FILE_PATH	file path	./logs/dev.log	Path for main log file
ERROR_LOG_PATH	file path	./logs/error.log	Path for error-only log file

* Smart default for console: Auto-enabled if no OTLP endpoint configured, otherwise disabled.

OpenTelemetry (OTLP) Configuration

Variable	Description	Example
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT	OTLP logs endpoint	http://127.0.0.1/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT	OTLP traces endpoint	http://127.0.0.1/v1/traces
OTEL_EXPORTER_OTLP_HEADERS	Custom headers (JSON)	{"Host":"otel.localhost"}

Runtime Environment

Variable	Values	Default	Description
NODE_ENV	development/production	development	Controls console format

Default Behavior

Scenario 1: No Configuration (Developer Just Installed)

# No environment variables set

Result:

• ✅ Console: Enabled (colored, human-readable)
• ✅ File: Enabled (./logs/dev.log + ./logs/error.log)
• ⚠️ OTLP: Falls back to localhost:4318 (may not reach anywhere)

Use Case: Developer installs library, sees logs immediately without configuration.

---

Scenario 2: With OTLP Configured (Production with Observability)

OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://otel-collector:4318/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://otel-collector:4318/v1/traces
NODE_ENV=production

Result:

• ❌ Console: Disabled (auto, logs go to OTLP)
• ✅ File: Enabled (always on unless explicitly disabled)
• ✅ OTLP: Configured endpoint

Use Case: Production deployment with observability stack, no noisy console output.

---

Scenario 3: OTLP Only (Clean Production)

OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://otel-collector:4318/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://otel-collector:4318/v1/traces
LOG_TO_FILE=false
LOG_TO_CONSOLE=false
NODE_ENV=production

Result:

• ❌ Console: Disabled (explicit)
• ❌ File: Disabled (explicit)
• ✅ OTLP: Configured endpoint (only output)

Use Case: Production with centralized observability, no local logging.

---

Scenario 4: File Only (Development Without Observability)

LOG_TO_CONSOLE=false
# No OTEL_EXPORTER_OTLP_LOGS_ENDPOINT set

Result:

• ❌ Console: Disabled (explicit)
• ✅ File: Enabled (default)
• ⚠️ OTLP: Falls back to localhost:4318

Use Case: Developer wants quiet console but structured file logs for debugging.

---

Scenario 5: Everything Enabled (Maximum Debugging)

LOG_TO_CONSOLE=true
LOG_TO_FILE=true
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://127.0.0.1/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://127.0.0.1/v1/traces
OTEL_EXPORTER_OTLP_HEADERS={"Host":"otel.localhost"}

Result:

• ✅ Console: Enabled (explicit)
• ✅ File: Enabled (explicit)
• ✅ OTLP: Configured endpoint
• All three outputs active simultaneously

Use Case: Troubleshooting issues with full visibility across all outputs.

---

Configuration Decision Matrix

OTLP Endpoint	LOG_TO_CONSOLE	LOG_TO_FILE	Console	File	OTLP	Use Case
Not set	Not set	Not set	✅ Auto	✅ Auto	❌	Developer default
Set	Not set	Not set	❌ Auto	✅ Auto	✅	Production with files
Set	false	false	❌	❌	✅	Clean production
Not set	false	true	❌	✅	❌	File-only logging
Set	true	true	✅	✅	✅	Full debugging

Console Output Formats

Development Mode (NODE_ENV ≠ production)

Colored, human-readable output with timestamps:

12:34:56 [INFO] my-service:myFunction - Operation completed
12:34:57 [ERROR] my-service:errorHandler - Request failed

Production Mode (NODE_ENV = production)

Structured JSON output for log aggregation:

{"timestamp":"2025-10-03T12:34:56.789Z","level":"info","service_name":"my-service","service_version":"1.0.0","session_id":"18df09dd-c321-43d8-aa24-19dd7c149a56","peer_service":"INTERNAL","function_name":"myFunction","message":"Operation completed","trace_id":"uuid-here","event_id":"uuid-here","log_type":"transaction","input_json":"null","response_json":"null"}

File Logging Features

Two Separate Files (Winston Best Practice)

1. Main Log (./logs/dev.log or custom LOG_FILE_PATH):

   • All log levels (TRACE, DEBUG, INFO, WARN, ERROR, FATAL)
   • Structured JSON format
   • Max size: 50MB, keeps 5 rotated files

2. Error Log (./logs/error.log or custom ERROR_LOG_PATH):

   • ERROR and FATAL levels only
   • Structured JSON format
   • Max size: 10MB, keeps 3 rotated files

File Rotation

Files automatically rotate when they reach max size:

• dev.log → dev.log.1 → dev.log.2 → ... → dev.log.5
• error.log → error.log.1 → error.log.2 → error.log.3

Oldest files are deleted when rotation limit is reached.

OTLP Configuration Examples

Local Development (sovdev-infrastructure)

# Use IP address 127.0.0.1 (Node.js cannot resolve .localhost domains)
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://127.0.0.1/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://127.0.0.1/v1/traces

# REQUIRED: Host header for Traefik routing
OTEL_EXPORTER_OTLP_HEADERS={"Host":"otel.localhost"}

Kubernetes (Inside sovdev-infrastructure)

# Use Kubernetes internal service DNS
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://otel-collector-opentelemetry-collector.monitoring.svc.cluster.local:4318/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://otel-collector-opentelemetry-collector.monitoring.svc.cluster.local:4318/v1/traces

# NO Host header needed - direct connection

Azure Application Insights

Azure Monitor supports OTLP ingestion natively. Choose between connection string or instrumentation key authentication.

Option 1: Using Connection String (Recommended)

# Azure Monitor OTLP ingestion endpoint (preview)
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://[your-region].in.applicationinsights.azure.com/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://[your-region].in.applicationinsights.azure.com/v1/traces

# Connection string from Application Insights resource
OTEL_EXPORTER_OTLP_HEADERS={"x-ms-qps-connection-string":"InstrumentationKey=12345678-1234-1234-1234-123456789012;IngestionEndpoint=https://[your-region].in.applicationinsights.azure.com/"}

Option 2: Using Instrumentation Key

# Azure Monitor OTLP endpoint
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://[your-region].in.applicationinsights.azure.com/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://[your-region].in.applicationinsights.azure.com/v1/traces

# Instrumentation key from Application Insights
OTEL_EXPORTER_OTLP_HEADERS={"x-ms-qps-instrumentation-key":"12345678-1234-1234-1234-123456789012"}

Finding Your Azure Configuration:

1. Azure Portal → Your Application Insights resource
2. Connection String: Overview blade → "Connection String" field
3. Instrumentation Key: Overview blade → "Instrumentation Key" field
4. Region: Check your resource location (e.g., westeurope, northeurope, eastus)

Example for Norwegian Red Cross (Norway deployment):

# Norway East region
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://norwayeast.in.applicationinsights.azure.com/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://norwayeast.in.applicationinsights.azure.com/v1/traces

# Use connection string (get from Azure Portal)
OTEL_EXPORTER_OTLP_HEADERS={"x-ms-qps-connection-string":"InstrumentationKey=YOUR_KEY;IngestionEndpoint=https://norwayeast.in.applicationinsights.azure.com/"}

Notes:

• Replace [your-region] with your Azure region (e.g., norwayeast, westeurope)
• Connection string method is recommended as it includes both key and endpoint
• OTLP support in Azure Monitor is in preview - check Azure Monitor OpenTelemetry documentation for updates
• Logs appear in the traces and customEvents tables in Application Insights

Grafana Cloud

# Grafana Cloud OTLP endpoint
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://otlp-gateway-prod-eu-west-0.grafana.net/otlp/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://otlp-gateway-prod-eu-west-0.grafana.net/otlp/v1/traces

# Grafana Cloud authentication
OTEL_EXPORTER_OTLP_HEADERS={"Authorization":"Basic BASE64_ENCODED_CREDENTIALS"}

Best Practices

1. Development

# Console + File (OTLP optional)
LOG_TO_CONSOLE=true
LOG_TO_FILE=true
NODE_ENV=development

Why: Immediate feedback via console, structured logs in files for debugging.

2. Staging/Testing

# File + OTLP (no console noise)
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://otel-collector:4318/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://otel-collector:4318/v1/traces
LOG_TO_FILE=true
NODE_ENV=production

Why: Centralized logs in observability stack, files for fallback/debugging.

3. Production

# OTLP only (clean, centralized)
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://your-observability-backend/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://your-observability-backend/v1/traces
OTEL_EXPORTER_OTLP_HEADERS={"Authorization":"Bearer YOUR_TOKEN"}
LOG_TO_FILE=false
LOG_TO_CONSOLE=false
NODE_ENV=production

Why: All logs go to centralized observability platform, no local disk usage.

4. Kubernetes/Cloud

# Console JSON + OTLP (stdout captured by platform)
LOG_TO_CONSOLE=true
LOG_TO_FILE=false  # Don't use pod filesystem
OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=http://otel-collector:4318/v1/logs
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://otel-collector:4318/v1/traces
NODE_ENV=production

Why: Kubernetes/cloud platforms capture stdout, file logging unnecessary.

Language-Specific Notes

TypeScript/JavaScript

Environment variables are read via process.env.

Python

Environment variables are read via os.getenv().

C#

Environment variables are read via Environment.GetEnvironmentVariable().

PHP

Environment variables are read via getenv().

Go

Environment variables are read via os.Getenv().

Rust

Environment variables are read via std::env::var().

Troubleshooting

No Logs Appearing

Check:

1. Is at least one output enabled? (console, file, or OTLP)
2. If file logging: Does the process have write permissions to ./logs/?
3. If OTLP: Is the endpoint reachable?

Solution:

# Enable console for immediate visibility
LOG_TO_CONSOLE=true

OTLP Connection Refused

Symptom: Logs appear in console/file but not in observability platform.

Check:

1. Is OTLP collector running and reachable?
2. Test connection: curl -X POST $OTEL_EXPORTER_OTLP_LOGS_ENDPOINT
3. Check headers if using Traefik/proxy

Solution:

# Verify endpoint
echo $OTEL_EXPORTER_OTLP_LOGS_ENDPOINT

# Test with curl
curl -v -X POST http://127.0.0.1/v1/logs \
  -H "Host: otel.localhost" \
  -H "Content-Type: application/json" \
  -d '{}'

File Permission Errors

Symptom: EACCES: permission denied, open './logs/dev.log'

Solution:

# Create logs directory with correct permissions
mkdir -p ./logs
chmod 755 ./logs

# Or change log path
LOG_FILE_PATH=/tmp/app.log

Security Considerations

Credential Removal

sovdev-logger automatically removes sensitive information from error logs:

• Authorization headers
• Bearer tokens
• API keys
• Password fields

Example:

const error = new Error('API call failed');
error.config = {
  headers: { Authorization: 'Bearer secret-token' }
};

// Logged as:
// exception.message: "API call failed"
// exception.config.headers.Authorization: "[REDACTED]"

Production Recommendations

1. Never log to files in production unless required for compliance
2. Use OTLP with authentication when sending to external collectors
3. Set NODE_ENV=production to disable colored console output
4. Rotate logs frequently if using file logging in production
5. Monitor disk usage if file logging is enabled

---

Quick Reference

Default (no config): Console + File Production: OTLP only (LOG_TO_FILE=false, LOG_TO_CONSOLE=false) Development: Console + File + OTLP (all enabled) Kubernetes: Console JSON + OTLP (LOG_TO_FILE=false)

Override any default: Set environment variable explicitly to true or false.