Java Instrumentation with OpenTelemetry

Prerequesites :
- opentelemetry-javaagent.jar : OpenTelemetry Java Releases
- Script for the agent environment variables configuration (setup.sh) :

    #!/bin/bash

    if [ $# -ne 3 ]; then
        echo "Usage: ./setup.sh [servicename] [endpoint] [logginglevel]"
        echo Example : ./setup.sh http://collector debug
        exit 1
    fi
        
    export OTEL_SERVICE_NAME=$1
    export OTEL_LOG_LEVEL=$3
    export OTEL_METRICS_EXPORTER=otlp
    export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
    export OTEL_EXPORTER_OTLP_ENDPOINT=$2:4318
    export OTEL_INSTRUMENTATION_OSHI_EXPERIMENTAL_METRICS_ENABLED=true
    export OTEL_INSTRUMENTATION_RUNTIME_TELEMETRY_EMIT_EXPERIMENTAL_TELEMETRY=true
    export OTEL_INSTRUMENTATION_HTTP_CLIENT_CAPTURE_REQUEST_HEADERS=Authorization,Cookie
    export OTEL_INSTRUMENTATION_HTTP_SERVER_CAPTURE_REQUEST_HEADERS=Authorization,Cookie

Usage : 
`./setup.sh [servicename] [endpoint] [logginglevel]`

+ __[servicename]__: service name.
+ __[endpoint]__ : url of Nudge Exporter (OTEL Collector).
+ __[logginglevel]__ : log level. Possible values : error, warn, info, debug, trace. Default value : info.

OSHI Core [Optional]

OSHI Core allows you to retrieve the “memory” metrics displayed in the Service/System tab.

Version 5.3.1 and above supported.

In pom.xml, add the required dependencies:

<!-- opentelemetry-->
    <dependency>
    <groupId>io.opentelemetry.instrumentation</groupId>
    <artifactId>opentelemetry-oshi</artifactId>
    <version>0.16.1</version>
    <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>com.github.oshi</groupId>
        <artifactId>oshi-core</artifactId>
        <version>5.3.1</version>
    </dependency>

In the Java application entry point, add the recording of metric observers.

import io.opentelemetry.instrumentation.oshi.ProcessMetrics;
import io.opentelemetry.instrumentation.oshi.SystemMetrics;
public static void main(String[] args) {
		/*
         * ...
         */
		SystemMetrics.registerObservers();
		ProcessMetrics.registerObservers();
	}

Launch of the application

java -javaagent:path/to/opentelemetry-javaagent.jar -jar myapp.jar

NodeJS Instrumentation with OpenTelemetry

Prerequesites :
- @opentelemetry/auto-instrumentations-node : Releases OpenTelemetry NodeJS

Dotnet Instrumentation with OpenTelemetry

OpenTelemetry .NET automatic instrumentation should work with all officially supported operating systems and versions of .NET. The minimum supported version of .NET Framework is 4.6.2. The following processor architectures are supported: x86 AMD64 (x86-64) ARM64 (experimental)

We will be using OpenTelemetry v1.14.0.

Prerequisites:
- Download OpenTelemetry Collector from the agents download page, which contains:
  - otelcol.exe (windows / linux)
  - config-template.yaml
  - env.psm1
  - env_vars.txt

Configuration

Configuration steps:
- In an Administrator powershell, run:
  - Import-Module ./env.psm1
  - Install-OpenTelemetryCore. This installs the OpenTelemetry files (v1.14.0) in the Program Files folder by default.
  - WARNING : this command will reset IIS. Register-OpenTelemetryForIIS -OTelServiceName <service_name> -AppPoolName <app_pool_name> -OtelExporterOtlpEndpoint <endpoint_url> where <service_name> refers to the service name, <app_pool_name> is the name of the application pool in IIS, and <endpoint_url> is the URL of the otelcol collector (http://localhost:4318).
    
    To verify that the environment variables have been set correctly: Open IIS. Go to the pool associated with the application, then select “Configuration Editor” and “Browse Configuration” (wait for the page to load). Open the configuration file (ApplicationHost.config or web.config) and verify that the environment variables have been set correctly (use the file env_vars.txt).
  - Configure the config-template.yaml file. Rename it to config.yaml. Replace <app_id> with the application ID you retrieved from your application on Nudge (type should be DOTNET). Replace <otel_service_name> with the <service_name> provided in the previous step.
```
  attributes/dotnetapp:
  actions:
  - action: insert
      key: nudge_application_id
      value: <app_id>
  include:
  # strict ou regexp
  match_type: strict
  # The Span service name must be equal to "petclinic"
  resources:
      - key: service.name
      value: <otel_service_name>
      - key: telemetry.sdk.language
      value: dotnet

  transform/dotnetapp:
      error_mode: ignore
      metric_statements:
      - context: datapoint
          statements:
          - set(attributes["nudge_application_id"], "<app_id>")
              where resource.attributes["service.name"] == "<otel_service_name>" and resource.attributes["telemetry.sdk.language"] == "dotnet"
```
  - Still in the config.yaml file, configure the Nudge endpoint:
```
  nudgehttp:
      endpoint: https://apm.atakama-technologies.com/
      pathCollect: collect/rawdata
```
  - Still in the config.yaml file, configure the log level:
```
  level: Warn
```
Starting otelcol.exe:
- ./otelcol.exe --config=file:./config.yaml --feature-gates=service.profilesSupport

Sharepoint

In the config.yaml :
- Uncomment the “uls” section and replace <uls_log_path> with the path to the logs generated by SharePoint. Default: C:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\LOGS*.log. Verify that this path exists. ``` uls: include:
  - ```
- Uncommment #, uls] in the section
```
  service:
    pipelines:
      logs:
      receivers: 
        receivers: [otlpnudge] #, uls]
```

Troubleshooting

The logs for the Nudge exporter (otelcol) are located in the folder where it was run.
OpenTelemetry logs are located in:
- Windows: %ProgramData%\OpenTelemetry .NET AutoInstrumentation\logs
- Linux: /var/log/opentelemetry/dotnet
- macOS: /var/log/opentelemetry/dotnet

Uninstall OpenTelemetry

In an Administrator PowerShell window, run: - Import-Module ./env.psm1 - Uninstall-OpenTelemetryCore - Unregister-OpenTelemetryForIIS --AppPoolName=<app_pool_name> where <app_pool_name> is the name of the pool specified during the installation of OpenTelemetry.