env_example.json

What is the purpose of env_example.json?

env_example.json is a contract between the Unit Developer and Pepeunit:

1. The Unit Developer guarantees that they will implement in the Unit logic all or some of the standard Pepeunit variables required for integration with Pepeunit.
2. Pepeunit guarantees that Users will be able to set the variables specified by the Unit Developer.
3. Pepeunit guarantees that it will automatically populate the standard variables defined in this file when the User first saves the env.

Structure

{   
    "WIFI_SSID": "ssid",
    "WIFI_PASS": "password",
    "PWM_FAN_PIN": 0,
    "DS18B20_PIN_NUM": 4,
    "REGULATOR_OPERATING_RANGE": 1000,
    "PUBLISH_SEND_INTERVAL": 1,
    "TEMP_MIN": 30,
    "TEMP_MAX": 60,
    "DUTY_MIN": 8192,
    "DUTY_MAX": 65535,
    "PU_DOMAIN": "unit.example.com",
    "PU_HTTP_TYPE": "https",
    "PU_APP_PREFIX": "/pepeunit",
    "PU_API_ACTUAL_PREFIX": "/api/v1",
    "PU_MQTT_HOST": "emqx.example.com",
    "PU_MQTT_PORT": 1883,
    "PU_MQTT_PING_INTERVAL": 30,
    "PU_AUTH_TOKEN": "jwt_token",
    "PU_SECRET_KEY": "32_bit_secret_key",
    "PU_ENCRYPT_KEY": "32_bit_encrypt_key",
    "PU_STATE_SEND_INTERVAL": 300,
    "PU_MIN_LOG_LEVEL": "Debug",
    "PU_MAX_LOG_LENGTH": 64
}

You can divide the variables into two categories: standard variables and developer environment variables.

Standard Pepeunit variables

Pepeunit reserves the following set of environment variables for a Unit:

Variable	Generated value in env.json	Purpose
PU_DOMAIN	PU_DOMAIN from Backend ENV	Domain name or IP address of the Pepeunit instance.
PU_HTTP_TYPE	PU_SECURE from Backend ENV	Connection type https/http to the Backend domain or IP, in the https/http format.
PU_APP_PREFIX	PU_APP_PREFIX from Backend ENV	Backend prefix.
PU_API_ACTUAL_PREFIX	PU_API_V1_PREFIX from Backend ENV	Prefix of the current API version of the Backend. Always points to the latest API version.
PU_MQTT_HOST	PU_MQTT_HOST from Backend ENV	Domain or IP address of the EMQX instance.
PU_MQTT_PORT	PU_MQTT_PORT from Backend ENV	Port for communication with EMQX, 1883 by default.
PU_MQTT_PING_INTERVAL	30	MQTT ping interval in seconds (30 seconds for everyone).
PU_AUTH_TOKEN	jwt token	Permanent access token of the Unit to the Pepeunit instance. This token is used to authorize subscriptions and publications in EMQX topics and is set automatically by the Backend.
PU_SECRET_KEY	32‑byte key in base64 format	Unique for each Unit. Convenient for signing or generating JWTs. Set automatically by the Backend.
PU_ENCRYPT_KEY	32‑byte key in base64 format	Unique for each Unit. Convenient for aes-gcm-256 encryption. Set automatically by the Backend.
PU_STATE_SEND_INTERVAL	PU_STATE_SEND_INTERVAL from Backend ENV	Interval for sending state to the standard state topic.
PU_MIN_LOG_LEVEL	Debug	Minimum log level that will be sent over MQTT and stored in the log.json file. For example, if you set it to Warning, then Debug and Info messages will not be sent.
PU_MAX_LOG_LENGTH	64	Maximum number of lines in log.json; old lines are removed from the beginning of the file.
PU_COMMIT_VERSION	Commit hash	Shows the current target version of the Unit. It has special behavior: it cannot be changed manually in the env.json editing UI; any attempt to change it will be ignored.

Unit Developer environment variables

The Unit Developer can create any environment variables whose names differ from the standard ones. The values defined in these variables will be shown as default values in the User interface.

DANGER

Since in the end it is the User who will fill in the variables manually, you must always provide pepeunit.toml and readme.md so that the User can understand what each variable controls.

DANGER

env.json is filled by the User based on the ENV generation mechanism.