Add apm_tracing mixin car to allow us to enable APM Tracing on es nodes (#85)

Add `apm_tracing` plugin to allow us to enable APM Tracing on ES nodes

[APM Tracing][1]

[1]: https://github.com/elastic/elasticsearch/blob/main/TRACING.md#how-is-tracing-configured

---------

Co-authored-by: Grzegorz Banasiak <[email protected]>

Author: Kevin Oberlies

cars/v1/apm-tracing.ini

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+[meta]
+description = APM Tracing
+type = mixin
+
+[config]
+base = apm_tracing
+
+[variables]
+apm_tracing_enabled = true
+apm_tracing_server_url = ""
+apm_tracing_global_labels = ""

cars/v1/apm_tracing/README.md

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+This directory contains the keystore configuration and configuration template for the `apm-tracing` mixin to enable APM Tracing.
+
+## Parameters
+
+This configuration allows to set the following parameters with Rally using `--car-params` in combination
+with `--cars="defaults,apm-tracing"`:
+
+- `apm_secret_token`: A string specifying the APM Tracing secretToken in order to properly send telemetry
+- `apm_tracing_server_url`: A string specifying the APM Tracing server to send telemetry data to.
+- `apm_tracing_global_labels`: A string specifying APM agent global labels added to every trace (useful for filtering).
+
+Example:
+
+`--car="defaults,apm-tracing" --car-params="apm_secret_token:XXXXX,apm_tracing_server_url:'https://example.com:443'"`
+
+Alternatively, the above settings can also be stored in a JSON file that can be specified via `--car-params`.
+
+Example:
+
+```json
+{
+  "apm_secret_token": "XXXXX",
+  "apm_tracing_server_url": "https://example.com:443"
+}
+```
+
+Save it as `params.json` and provide it to Rally with `--car="defaults,apm-tracing" --car-params="/path/to/params.json"`.

cars/v1/apm_tracing/config.py

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+import logging
+import os
+import shlex
+import subprocess
+
+from esrally import exceptions
+from esrally.utils import process
+
+LOGGER_NAME = "esrally.provisioner.apm_tracing"
+
+
+def resolve_binary(install_root, binary_name):
+    return os.path.join(install_root, "bin", binary_name)
+
+
+def resolve_keystore_config(install_root):
+    return os.path.join(install_root, "config", "elasticsearch.keystore")
+
+
+def create_keystore(install_root, keystore_binary, env):
+    logger = logging.getLogger(LOGGER_NAME)
+
+    keystore_create_command = "{keystore} -s create".format(keystore=keystore_binary)
+
+    return_code = process.run_subprocess_with_logging(keystore_create_command, env=env)
+
+    if return_code != 0:
+        logger.error(
+            "%s has exited with code [%d]", keystore_create_command, return_code
+        )
+        raise exceptions.SystemSetupError(
+            "Could not initialize a keystore. Please see the log for details."
+        )
+
+
+def add_property_to_keystore(keystore_binary, property_name, property_value, env):
+    logger = logging.getLogger(LOGGER_NAME)
+
+    echo_value = subprocess.Popen(["echo", property_value], stdout=subprocess.PIPE)
+
+    keystore_command = "{keystore} --silent add --stdin {key}".format(
+        keystore=keystore_binary, key=property_name
+    )
+
+    return_code = process.run_subprocess_with_logging(
+        keystore_command, stdin=echo_value.stdout, env=env
+    )
+
+    if return_code != 0:
+        logger.error("%s has exited with code [%d]", keystore_command, return_code)
+        raise exceptions.SystemSetupError(
+            "Could not add APM tracing keystore secure setting [{}]. Please see the log for details.".format(
+                property_name
+            )
+        )
+
+
+def configure_keystore(config_names, variables, **kwargs):
+    logger = logging.getLogger(LOGGER_NAME)
+    secret_token = variables.get("apm_secret_token")
+
+    # skip keystore configuration entirely if any of the mandatory params is missing
+    if not secret_token:
+        logger.warning(
+            "Skipping keystore configuration for apm-tracing "
+            "as mandatory car-params [`apm_secret_token`] was not supplied",
+        )
+        return False
+
+    keystore_binary_filename = "elasticsearch-keystore"
+    install_root = variables["install_root_path"]
+    keystore_binary = resolve_binary(install_root, keystore_binary_filename)
+    env = kwargs.get("env")
+
+    if not os.path.isfile(resolve_keystore_config(install_root)):
+        create_keystore(install_root, keystore_binary, env)
+
+    add_property_to_keystore(keystore_binary, "telemetry.secret_token", secret_token, env)
+
+    # Success
+    return True
+
+
+def register(registry):
+    registry.register("post_install", configure_keystore)

cars/v1/apm_tracing/templates/config/elasticsearch.yml

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+
+telemetry.tracing.enabled: {{apm_tracing_enabled}}
+{% if apm_tracing_server_url -%}
+telemetry.agent.server_url: {{apm_tracing_server_url}}
+{%- endif %}
+{% if apm_tracing_global_labels -%}
+telemetry.agent.global_labels: {{apm_tracing_global_labels}}
+{%- endif %}
+