service.toml File

A service configuration file is a text file using the TOML syntax to adjust various information related to it.

Currently, it must contain at least the following information:

• service name
• service category
• version (in semver format)
• service language
• product to which the service belongs

Example:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"

Environment Variables

Services may need specific environment variables. These variables must also be declared in this configuration file, and allow for validation of their existence or not during the service initialization.

These variables are declared in the envs object, as follows:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"
envs = [ "VARIABLE_1", "VARIABLE_2" ]

Initial Log Message Level

It is possible to adjust the initial level of log messages displayed by a service. The log_level object allows you to adjust this information as follows:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"
log_level = "debug"

Currently, the following values are supported:

• debug
• info
• warn
• error

Custom Service Configurations

A special section with the name service is available for adding custom service configurations, which are accessible only within it.

These configurations are loaded by Mikros, being made available through the Service.CustomDefinitions API, being returned in the format map[string]interface{}.

Example:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"

[service]
custom_definition_1 = "Hello World!"
custom_definition_2 = 42

This information will be available to the service as follows:

type server struct {
	*mikros.Service
}

func (s *server) Foo() {
	cfg := s.Service.CustomDefinitions()
	customDefinition1 := cfg["custom_definition_1"].(string)
	customDefinition2 := cfg["custom_definition_2"].(int)
}

Changing Host and Port of Coupled Services

Eventually, there may be a need to have a custom hostname and port to access a particular service coupled to the service itself. By default, Mikros uses fixed values for this information (which can be changed via environment variables).

To override these values and allow establishing a connection in a customized way, the service configuration file provides the clients section for this purpose. Internally, as it is an object of type map, it can be used as follows:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"

[clients.service_name]
host = "localhost"
port = 10942

Features

By default, every feature provided by Mikros is initialized as disabled in the service. This way, they need to be explicitly "turned on" for use.

Every feature is always accessed by a main object called features. The following example shows how to "turn on" the tracing feature of a given service:

name = "alert"
type = "grpc"
version = "v0.1.0"
language = "go"
product = "SDS"

[features.tracing]
enabled = true