Sms modem reader

The application reads sms from the gsm huawei modem (tested on models: E173, E352b) using AT commands and sends these sms to the specified webhook using the post request. It also periodically checks the balance and exports it to metrics on uri /metrics in prometheus format.

Setup

curl -L https://github.com/identw/sms-modem-reader/releases/latest/download/sms-modem-reader-amd64 -o /usr/local/bin/sms-modem-reader
chmod +x /usr/local/bin/sms-modem-reader

To run:

/usr/local/bin/sms-modem-reader

If you need to change the default options, then export the required environment variables. For example:

export WEBHOOK_URL=https://example.com/webhook
export BALANCE_USSD="*105#"
/usr/local/bin/sms-modem-reader

For convenience, you can create a systemd service: /etc/systemd/system/sms-modem-reader.service:

[Unit]
Description=Sms modem reader

[Install]
WantedBy=multi-user.target

[Service]
EnvironmentFile=-/etc/default/sms-modem-reader
ExecStart=/usr/local/bin/sms-modem-reader
Restart=on-failure

Enable service:

systemctl daemon-reload
systemctl enable sms-modem-reader

In this file, you can specify any available environment variables /etc/default/sms-modem-reader:

 WEBHOOK_URL=https://example.com/webhook
 BALANCE_USSD="*105#"

If your modem does not work in modem mode, you can switch it to this mode using the program usb_modeswitch (package usb-modeswitch in ubuntu/debian). To do this, you can add another udev rule: /etc/udev/rules.d/99-sms-modem-reader.rules:

ATTRS{idVendor}=="12d1",ATTRS{idProduct}=="1506",RUN+="/usr/sbin/usb_modeswitch -v 12d1 -p 1506",TAG+="systemd"

All udev attributes can be viewed with the command udevadm info -a / dev / ttyUSB0

idVendor and idProduct can be found with lsusb. For example:

# lsusb
...
Bus 003 Device 002: ID 12d1:1506 Huawei Technologies Co., Ltd. Modem/Networkcard
...

12d1 - idVendor
1506 - idProduct

webhook

You can specify url using the environment variable WEBHOOK_URL. For example: export WEBHOOK_URL=https://example.com/sms

Requst type: POST
Content-type: application/json
Body: {"message": "text sms"}

Check balance

The balance is checked using a USSD request, which can be specified through the environment variable BALANCE_USSD. The balance is read using a regular expression, which is specified using the environment variable BALANCE_REGEXP in the golang regex syntax. The application tries to calculate the balance both from the response to the USSD request and from incoming sms. In regular expression, the first captured group will be considered the balance.

Environment variables

• METRIC_PORT (default: "40111") - port for prometheus metrics
• METRIC_LISTEN_IP (default: "0.0.0.0") - ip address of the interface for prometheus metrics
• BALANCE_USSD (default: "*122#") - USSD request to check balance
• BALANCE_REGEXP (default: "^.составляет (-?[0-9]+(.[0-9]+)?) руб.$") - regex to pull the current balance out of the message. The current balance will be the first captured group in the regular expression (that is, the first parentheses). The syntax used is https://golang.org/pkg/regexp/syntax/
• INTERVAL_READ_SMS (default: "10") - interval in seconds with which you want to check incoming sms
• INTERVAL_CHECK_BALANCE (default: "86400") - interval in seconds with which to check the current balance
• WEBHOOK_URL (default: "http://127.0.0.1/webhook") - url where sms messages will be sent
• WEBHOOK_BASIC_AUTH (умолчание: "false") - enables / disables http authentication for sending webhooks
• WEBHOOK_BASIC_AUTH_USER (умолчание: "admin") - when http authentication is enabled, this user is used
• WEBHOOK_BASIC_AUTH_PASS (умолчание: "") - when http authentication is enabled, this password is used
• SERIAL_FILE (default: "/dev/ttyUSB0") - serial port file
• SERIAL_BAUD (default: "9600") - serial port baud rate (bps)
• SERIAL_STOP_BITS (default: "1") - the number of stop bits. Possible values: "1", "2", "15"
• SERIAL_PARITY (default: "N") - indicates the presence and type of parity bit. Possible values: "N", "O", "E", "M", "S"
• SERIAL_SIZE (default: "8") - the number of bits that frame start and stop bits

prometheus metrics

Metrics can be obtained at url: http://METRIC_LISTEN_IP:METRIC_PORT/metrics

metric	type	description
sms_reader_balance	guage	current balance
sms_reader_balance_last_check	guage	unix timestamp last check
sms_reader_sms_last_status	guage	sms last read status, 0 - successful, 1 - failed to read
sms_reader_webhook_last_status	guage	status of the last submission to webhook, 0 - successful, 1 - failed to send

Example metrics:

# HELP sms_reader_balance current balance
# TYPE sms_reader_balance gauge
sms_reader_balance 350.36
# HELP sms_reader_balance_last_check unix timestamp last check balance
# TYPE sms_reader_balance_last_check gauge
sms_reader_balance_last_check 1.597837689e+09
# HELP sms_reader_sms_last_status read sms correct, 1 = fail, 0 = success
# TYPE sms_reader_sms_last_status gauge
sms_reader_sms_last_status 0
# HELP sms_reader_webhook_last_status send webhook last send fail, 1 = fail, 0 = success
# TYPE sms_reader_webhook_last_status gauge
sms_reader_webhook_last_status 1