From c1a8b8dd177250d28be02b2a15bc04764ea54f80 Mon Sep 17 00:00:00 2001
From: William Reid <william.reid@uconn.edu>
Date: Wed, 13 Feb 2019 22:47:31 -0500
Subject: [PATCH] Commit of skeleton code for the real generator server

---
 .gitignore   |   3 ++
 README.md    | Bin 42 -> 162 bytes
 dataTypes.go |   6 +++
 hello.go     |   9 ----
 server.go    | 115 +++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 124 insertions(+), 9 deletions(-)
 create mode 100644 .gitignore
 create mode 100644 dataTypes.go
 delete mode 100644 hello.go
 create mode 100644 server.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f394ffe
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.exe
+.idea/*
+
diff --git a/README.md b/README.md
index 863462b85441d6dc9406d334cc0e10e5eda013c4..08fb68f7f6508b1fe0bb4dff48bdb8be94e262a8 100644
GIT binary patch
literal 162
zcmZXOOA3HM3`4UPyhFjYxA6jlf7B6FJihumx|1PkLz;H(tB|Qzs|Yp)9a^cS_N33m
vxiUE_4H|Lm<3Lw4zwkzqM&H4^CUP_IZSk9G(1!2(4QELDf7|o^m-qGq<_{iI

delta 5
McmZ3)s5L<g00jF1hyVZp

diff --git a/dataTypes.go b/dataTypes.go
new file mode 100644
index 0000000..580dff5
--- /dev/null
+++ b/dataTypes.go
@@ -0,0 +1,6 @@
+package main
+
+type StampedReading struct {
+	Timestamp int
+	Value     interface{}
+}
diff --git a/hello.go b/hello.go
deleted file mode 100644
index 17957ee..0000000
--- a/hello.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package main
-
-import (
-	"fmt"
-)
-
-func main() {
-	fmt.Printf("hello, world\n")
-}
diff --git a/server.go b/server.go
new file mode 100644
index 0000000..c60dbcb
--- /dev/null
+++ b/server.go
@@ -0,0 +1,115 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"math/rand"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+func main() {
+	dataReadChan := make(chan map[string]StampedReading) // Channel to handle data readings
+	dataBuffer := make(map[string][]StampedReading)      // Map to store readings in until they are sent
+
+	go dataReadLoop(dataReadChan)                    // Start our async read loop
+	dataSendTick := time.NewTicker(time.Second * 10) // Ticker to send data
+
+	// Non-blocking channel reads
+	for {
+		select {
+
+		case reading := <-dataReadChan:
+			// We got a data packet
+			fmt.Printf("New reading: %v\n", reading)
+
+			// Put our reading in the map
+			for metric, value := range reading {
+				if record, found := dataBuffer[metric]; !found {
+					dataBuffer[metric] = []StampedReading{value}
+				} else {
+					dataBuffer[metric] = append(record, value)
+				}
+			}
+
+		case <-dataSendTick.C:
+			// Time to send some data
+			if len(dataBuffer) > 0 { // Only send if we have data
+				if err := sendData(dataBuffer); err != nil { // Something went wrong
+					fmt.Printf("Error sending data: %v\n", err)
+				} else { // Data sent, clear the map
+					dataBuffer = make(map[string][]StampedReading)
+				}
+			} else { // There was no data to send
+				fmt.Println("Got data send signal but buffer is empty")
+				// TODO: manage the map so that it doesn't run out of memory and kill everything if we don't send data
+			}
+
+		}
+	}
+}
+
+func dataReadLoop(x chan map[string]StampedReading) {
+	for {
+		// Send our read packets down the channel
+		// TODO: error handling
+		x <- readData()
+		time.Sleep(time.Second)
+	}
+}
+
+func readData() map[string]StampedReading {
+	// TODO: modbus
+	return map[string]StampedReading{
+		"oil.temp": {
+			Timestamp: int(time.Now().Unix()),
+			Value:     rand.Intn(150),
+		},
+		"fuel.temp": {
+			Timestamp: int(time.Now().Unix()),
+			Value:     rand.Intn(150),
+		},
+	}
+}
+
+func sendData(data map[string][]StampedReading) error {
+
+	url := "http://localhost:8081/data"
+	jsonStr, err := json.Marshal(data)
+	if err != nil {
+		fmt.Printf("Error marshalling data: %v\n", err)
+		return err
+	}
+
+	fmt.Printf("Sending json: %v\n", string(jsonStr))
+
+	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonStr))
+	fillHeader(req)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			fmt.Printf("Error: %v", err)
+		}
+	}()
+
+	fmt.Println("response Status:", resp.Status)
+	if resp.StatusCode != 200 {
+		fmt.Printf("Received a non-200 response: %v\n", resp.StatusCode)
+	}
+
+	return nil
+}
+
+func fillHeader(req *http.Request) { // Sets the uuid and timestamp for a request
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("uuid", "0000001bcd3f")	// TODO: get this from somewhere
+	req.Header.Set("time", strconv.FormatInt(time.Now().Unix(), 10))
+}