Initial commit.

.gitignore

@@ -0,0 +1,4 @@
+tmp/
+bin/
+.idea/
+*.iml

Makefile

@@ -0,0 +1,18 @@
+all: bin native linux-arm64 linux-amd64
+
+.PHONY: clean native linux-arm64 linux-amd64
+
+clean:
+	-rm -Rf ./bin
+
+bin:
+	mkdir -p bin
+
+native:
+	CGO_ENABLED=0 go build -o bin/smlToHttp-native
+
+linux-arm64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -o bin/smlToHttp-linux-arm64
+
+linux-amd64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o bin/smlToHttp-linux-amd64

README.md

@@ -0,0 +1,132 @@
+# SML to HTTP proxy
+
+This application is designed to read a binary SML stream via TCP/IP and export all values via a simple HTTP REST API using JSON.
+It is intended to be used with home automation systems to read the values of smart meters.
+In the most basic configuration, a serial to TCP/IP converter in conjunction with a D0 read head can be used.
+
+## Building
+
+To build this application first install Go 1.20 or later.
+Then run the provided Makefile:
+
+```shell
+make
+```
+
+This builds multiple binaries:
+
+| Path                       | Usage                                                                       |
+|----------------------------|-----------------------------------------------------------------------------|
+| bin/smlToHttp-linux-native | Built for the computer building the application                             |
+| bin/smlToHttp-linux-amd64  | Built for a normal desktop computer                                         |
+| bin/smlToHttp-linux-arm64  | Built for a computer running the ARM64 architecture, e. g. a Raspberry Pi 4 |
+
+Feel free to extend the Makefile if your use case is not dealt with.
+
+## Usage
+
+First create a configuration file named `config.yml`.
+Replace the IP address serial to TCP/IP converter in the meters section.
+Note: You can add multiple meters, not just one.
+
+To disable the HTTP request log, set `web/disable_request_log` to `true`.
+Similarly, you can disable the SML reception log by setting `meters/disable_reception_log` to `true` on a per meter basis.
+
+```yaml
+web:
+  address: 127.0.0.1:11123
+  disable_request_log: false
+
+meters:
+  - id: my_smartmeter
+    address: 192.168.0.1:8234
+    reconnect_delay: 10
+    read_timeout: 5
+    connect_timeout: 10
+    debug: false
+    disable_reception_log: false
+```
+
+Then start the application:
+
+```shell
+./bin/smlToHttp-native -config config.yml
+```
+
+The log should now yield that the connection is successful and that SML frames are being decoded.
+You can then try to access the API:
+
+```shell
+curl http://127.0.0.1:11123/processImage
+```
+
+The response should look something along the lines of:
+
+```json
+{
+  "meters": {
+    "my_smartmeter": {
+      "connected": true,
+      "lastUpdate": "2023-06-06T13:12:10.064515753Z",
+      "values": {
+        "1-0:1.8.0*255": {
+          "value": 123456.7,
+          "unit": 30
+        },
+        "1-0:2.8.0*255": {
+          "value": 234567.8,
+          "unit": 30
+        },
+        "1-0:16.7.0*255": {
+          "value": -3210,
+          "unit": 27
+        },
+        "... continued ...": {}
+      }
+    }
+  }
+}
+```
+
+The response above has been truncated a bit, but you should get the gist out of it.
+In the example above, the OBIS key `1-0:1.8.0*255` yields a value of `123456.7`, which represents 123456.7 kWh of retrieved energy from the energy provider.
+Also, we have sold 234567.8 kWh of energy to the service provider.
+And our current power draw is -3210 W, so we are currently selling 3210 Watts to the service provider.
+A positive value here would mean that we currently buy energy from the provider.
+Please refer to your smart meter user manual for exported OBIS items.
+
+## Integration with OpenHAB
+
+The proxy is currently in production use in combination with OpenHAB, but may of course serve other systems.
+For this example, the HTTP binding and the JSONPath transformation addons are required.
+An example configuration might be:
+
+```text
+Thing http:url:smlToHttp "SML to HTTP" [
+    baseURL="http://127.0.0.1:11123/processImage",
+    refresh=2
+] {
+    Channels:
+        Type number : my_smartmeter_1_8_0 "My SmartMeter 1.8.0" [ stateTransformation="JSONPATH:$.meters.my_smartmeter.values.['1-0:1.8.0*255'].value", unit="Wh", mode="READONLY" ]
+        Type number : my_smartmeter_2_8_0 "My SmartMeter 2.8.0" [ stateTransformation="JSONPATH:$.meters.my_smartmeter.values.['1-0:2.8.0*255'].value", unit="Wh", mode="READONLY" ]
+        Type number : my_smartmeter_16_7_0 "My SmartMeter 16.7.0" [ stateTransformation="JSONPATH:$.meters.my_smartmeter.values.['1-0:16.7.0*255'].value", unit="W", mode="READONLY" ]
+}
+```
+
+## License
+
+    SML to HTTP proxy
+    Copyright (C) 2023  Stephan Brunner
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.

config.go

@@ -0,0 +1,21 @@
+package main
+
+type config struct {
+	Web    webConfig     `yaml:"web"`
+	Meters []meterConfig `yaml:"meters"`
+}
+
+type webConfig struct {
+	Address           string `yaml:"address"`
+	DisableRequestLog bool   `yaml:"disable_request_log"`
+}
+
+type meterConfig struct {
+	Id                  string `yaml:"id"`
+	Address             string `yaml:"address"`
+	ReconnectDelay      int    `yaml:"reconnect_delay"`
+	ReadTimeout         int    `yaml:"read_timeout"`
+	ConnectTimeout      int    `yaml:"connect_timeout"`
+	DisableReceptionLog bool   `yaml:"disable_reception_log"`
+	Debug               bool   `yaml:"debug"`
+}

go.mod

@@ -0,0 +1,9 @@
+module smlToHttp
+
+go 1.20
+
+require (
+	github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3
+	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1
+	gopkg.in/yaml.v3 v3.0.1
+)

go.sum

@@ -0,0 +1,8 @@
+github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3 h1:aQKxg3+2p+IFXXg97McgDGT5zcMrQoi0EICZs8Pgchs=
+github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3/go.mod h1:9/etS5gpQq9BJsJMWg1wpLbfuSnkm8dPF6FdW2JXVhA=
+golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 h1:k/i9J1pBpvlfR+9QsetwPyERsqu1GIbi967PQMq3Ivc=
+golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

logger.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"sync"
+)
+
+type logger interface {
+	newSubLogger(prefix string) logger
+
+	Printf(fmt string, v ...any)
+}
+
+type rootLogger struct {
+	lock *sync.Mutex
+}
+
+func newLogger() logger {
+	return &rootLogger{
+		lock: &sync.Mutex{},
+	}
+}
+
+func (l *rootLogger) newSubLogger(prefix string) logger {
+	return &subLogger{
+		parent: l,
+		prefix: prefix,
+	}
+}
+
+func (l *rootLogger) Printf(fmt string, v ...any) {
+	l.lock.Lock()
+	defer l.lock.Unlock()
+
+	log.Printf(fmt, v...)
+}
+
+type subLogger struct {
+	parent logger
+	prefix string
+}
+
+func (s *subLogger) newSubLogger(prefix string) logger {
+	return &subLogger{
+		parent: s,
+		prefix: prefix,
+	}
+}
+
+func (s *subLogger) Printf(format string, v ...any) {
+	str := fmt.Sprintf(format, v...)
+	s.parent.Printf("%s: %s", s.prefix, str)
+}

main.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"net/http"
+	"os"
+
+	"gopkg.in/yaml.v3"
+)
+
+func main() {
+	configFileFlag := flag.String("config", "", "The config file")
+
+	flag.Parse()
+
+	if len(*configFileFlag) == 0 {
+		print(
+			"SML to HTTP proxy\n" +
+				"  Copyright (C) 2023  Stephan Brunner\n" +
+				"  This program comes with ABSOLUTELY NO WARRANTY.\n" +
+				"  This is free software, and you are welcome to redistribute it\n" +
+				"  under the terms of the GNU GPL v3; see LICENSE.txt and README.md for details.\n\n" +
+				"  The source code is available at https://github.com/boomer41/SML-to-HTTP-proxy\n\n",
+		)
+		flag.Usage()
+		return
+	}
+
+	cfg, err := loadConfig(*configFileFlag)
+
+	if err != nil {
+		log.Fatalf("failed to load configuration: %v", err)
+	}
+
+	l := newLogger()
+
+	image := newProcessImageManager(cfg)
+	exporter := newWebExporter(image, l.newSubLogger("web"))
+	meters := newMeterManager(cfg.Meters, image, l.newSubLogger("meterManager"))
+
+	errorChannel := make(chan error)
+
+	go func() {
+		err := exporter.serve(&cfg.Web)
+
+		if err == http.ErrServerClosed {
+			return
+		}
+
+		errorChannel <- err
+	}()
+
+	go func() {
+		err := meters.run()
+		errorChannel <- err
+	}()
+
+	for {
+		err := <-errorChannel
+
+		log.Fatalf("subsystem returned error: %v", err)
+	}
+}
+
+func loadConfig(path string) (*config, error) {
+	var configContent []byte
+	{
+		f, err := os.OpenFile(path, os.O_RDONLY, 0)
+
+		if err != nil {
+			return nil, err
+		}
+
+		defer f.Close()
+
+		configContent, err = io.ReadAll(f)
+
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var c config
+	err := yaml.Unmarshal(configContent, &c)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &c, nil
+}