Env entity
The Env service entity allows running entities to pass arguments and environment variables. When started, each entity automatically sends a request to the Env entity and receives the necessary data.
By including the Env entity in the solution, you can mount file systems when VFS is started, connect one client entity to two VFS entities, and perform many other tasks.
To use the Env entity in your solution, the following is required:
1. Develop the code of the Env entity by using macros from env/env.h.
2. Build an image of the entity by linking it to the env_server library.
3. In the init description, indicate that the Env entity must be started and connected to the selected entities (Env acts a server in this case). The channel name is defined by the ENV_SERVICE_NAME macro declared in the env/env.h file.
4. Include the Env entity image in the solution image.
Env entity code
The code of the Env entity utilizes the following macros and functions declared in the env/env.h file:
ENV_REGISTER_ARGS(name,argarr)– arguments from theargarrarray will be passed to the entity namedname.ENV_REGISTER_VARS(name,envarr)– environment variables from theenvarrarray will be passed to the "name" entity.ENV_REGISTER_PROGRAM_ENVIRONMENT(name,argarr,envarr)– arguments and environment variables will be passed to the entity namedname.envServerRun()– initialize the server part of the entity so that it can respond to requests.
Example:
env.c
int main(int argc, char** argv)
{
const char* NetVfsArgs[] = {
"-l", "devfs /dev devfs 0",
"-l", "romfs /etc romfs 0"
};
ENV_REGISTER_ARGS("VFS", NetVfsArgs);
envServerRun();
return EXIT_SUCCESS;
}
Init.yaml example for use of the Env entity
In the next example, the Client entity will be connected to the Env entity whose image is located in the env folder:
init.yaml
entities:
- name: env.Env
- name: Client
connections:
- target: env.Env
id: {var: ENV_SERVICE_NAME, include: env/env.h}