Configuration

In this section, we will explore how to configure Mtracer for system testing.

Configuration methods

Mtracer supports several configuration methods to meet the needs of every developer and every testing environment. The supported methods are listed below, in descending order of priority (from most to least relevant):

1. Command line flags: it is possible to pass some configuration parameters directly from the command line during execution;
2. Environment variables: it is possible to define environment variables directly in the system or within a .env file in the project root (in the latter case, they will be loaded automatically);
3. YAML configuration file: it is possible to define a configuration file in YAML format by specifying its path with the --config or -c flag. If no path is specified, Mtracer will look for a file named mtracer.yaml in the project root by default.

If none of these options are used, Mtracer will apply default values.
Furthermore, if a parameter is specified in more than one configuration method, the value provided by the method with the highest priority will be used.

Configuration parameter nomenclature

Configuration parameters follow a specific nomenclature depending on the method used. The conventions for each method are shown below:

• Command line flags: parameters can be explored via the mtracer --help or mtracer -h command. Flags generally consist of words separated by hyphens (-) and can be specified in long (e.g., --config) or short (e.g., -c) form.
• Environment variables: environment variables must be written in uppercase, with words separated by underscores (_), for example MTRACER_BACKEND_TYPE. It is important to note that all variables must have the MTRACER_ prefix to be recognized.
• YAML configuration file: parameters are specified using standard key: value syntax (e.g., backend_type: jaeger).

It is essential to understand how YAML names are converted into environment variables. An explanatory example is provided below:

backend_type: openobserve
openobserve:
  base_url: http://localhost:5080

MTRACER_BACKEND_TYPE=openobserve
MTRACER_OPENOBSERVE_BASE_URL=http://localhost:5080

In the subsequent documentation, to refer to a variable defined in YAML, the syntax struct.variable_name will be used, indicating a configuration of this type:

struct:
    variable_name: value

Generic configuration parameters

The command line flags described in this section are available for all Mtracer commands.

Observability backend configuration

The following sections illustrate the necessary configurations depending on the backend used. If a backend is not on the list, it means that it is currently not supported by Mtracer.