# Apache HttpClient

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> OpenTelemetry Java agent instrumentation

This instrumentation enables HTTP client spans and HTTP client metrics for version 4 of the Apache HttpClient.

- **Name**: `apache-httpclient-4.0`
- **Scope**: `io.opentelemetry.apache-httpclient-4.0`
- **Target versions**: `io.dropwizard:dropwizard-client:(,3.0.0)`, `org.apache.httpcomponents:httpclient:[4.0,)`
- **Library**: https://hc.apache.org/index.html

## Telemetry

- **Metrics**: `http.client.request.duration`
- **Span attributes**: `error.type`, `http.request.method`, `http.request.method_original`, `http.response.status_code`, `network.protocol.version`, `peer.service`, `server.address`, `server.port`, `url.full`, `service.peer.name`

## Configuration

| Option | Type | Default | Description |
| --- | --- | --- | --- |
| `otel.instrumentation.common.peer-service-mapping` | map |  | Used to specify a mapping from host names or IP addresses to peer services. |
| `otel.instrumentation.http.client.capture-request-headers` | list |  | List of HTTP request headers to capture in HTTP client telemetry. |
| `otel.instrumentation.http.client.capture-response-headers` | list |  | List of HTTP response headers to capture in HTTP client telemetry. |
| `otel.instrumentation.http.client.emit-experimental-telemetry` | boolean | false | Enable the capture of experimental HTTP client telemetry. Adds the `http.request.body.size` and `http.response.body.size` attributes to spans, and records `http.client.request.body.size` and `http.client.response.body.size` metrics. |
| `otel.instrumentation.http.known-methods` | list | CONNECT,DELETE,GET,HEAD,OPTIONS,PATCH,POST,PUT,TRACE | Configures the instrumentation to recognize an alternative set of HTTP request methods. All other methods will be treated as `_OTHER`. |
| `java.common.http.client.url_template_rules` | list |  | Rules for deriving low-cardinality URL templates (routes) from HTTP client request URLs. Only applied when experimental HTTP client telemetry is enabled. |
| `otel.instrumentation.sanitization.url.experimental.sensitive-query-parameters` | list | AWSAccessKeyId,Signature,sig,X-Goog-Signature | List of URL query parameter names whose values are redacted in URL attributes. See https://opentelemetry.io/docs/specs/semconv/http/http-spans. |

## Data

- **JSON**: [/data/javaagent/instrumentations/apache-httpclient-4.0/apache-httpclient-4.0-26e6e4cb5951.json](/data/javaagent/instrumentations/apache-httpclient-4.0/apache-httpclient-4.0-26e6e4cb5951.json)
- **Explore**: [/java-agent/instrumentation/apache-httpclient-4.0](/java-agent/instrumentation/apache-httpclient-4.0)