big update and rewrite of web apps chapter

README.markdown

@@ -1,3 +1,39 @@
 Resources for http://GoTutorial.net
 
 see the above website for details.
+
+
+### Beginner Go
+
+- Lesson 01: The Basic Basics
+	- Intro to Syntax, Numbers, Strings
+- Lesson 02: Go with the Flow
+	- Expressions, Statements & Flow Control
+- Lesson 03: Intro To Types
+	- Types, Arrays, Slices, Maps & Structs
+
+### Advanced Go
+
+
+- Lesson 04: Composition
+	- Embedded Fields & Interfaces
+- Lesson 05: Concurrency
+	- Goroutines & Channels
+- Lesson 06: Toolchain
+	- Compiling, Formatting, Testing, Profiling & More
+- Lesson 07: Idiomatic Go
+	- Idiomatic Go
+- Lesson 08: Web Apps in Go
+	- net/http, net/http/httptest, html/template, database/sql
+- Lesson 09: JSON, JSON, JSON
+	- Encoder/Decoder, Anonymous Fields, Marshaler/Unmarshaler Interface, RawMessage
+- Lesson 10: Testing
+	- Testing, Benchmarking, Coverage, httptest and more
+- Lesson 12: I/O
+	- Readers, Writers & Buffers
+
+### Other
+
+- Lesson 11: Deployment
+	- Build/Release, Containers & A Case Study
+

shortlink/slv0/.gitignore

@@ -0,0 +1,2 @@
+slv*
+gox_build.log

shortlink/slv0/README.markdown

@@ -0,0 +1,5 @@
+
+
+## Usage
+
+    ./build_all.sh

shortlink/slv0/build_all.sh

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+#!/bin/sh
+
+# if one of our commands returns an error, stop execution of this script
+set -o errexit 
+
+COMPONENT="shortlink"
+GO_COMMAND="go"
+
+# generate
+echo "************************"
+echo "$GO_COMMAND generate"
+$GO_COMMAND generate
+
+# build on the native or default platform
+echo "************************"
+echo "building native platform"
+$GO_COMMAND build
+
+echo "************************"
+echo "vetting native platform"
+$GO_COMMAND vet
+
+# test on the native or default platform
+echo "************************"
+echo "testing native platform"
+$GO_COMMAND test
+
+# I like gox as a cross compilation tool: https://github.com/mitchellh/gox
+# install with:
+# go get github.com/mitchellh/gox
+
+# build for our test or deployment platforms
+# normally we do local development on darwin/amd64 and deploy to linux/amd64.
+# feel free to add or remove if your situation differs
+# also, in the normal case, most of the output of gox is redundant with
+# the output from go build above, so in the normal case, we just 
+# redirect to a build log
+
+# currently gox doesn't seem to support vgo...
+
+GOX_BUILD_LOG="gox_build.log"
+date >> $GOX_BUILD_LOG
+echo "************************"
+echo "crosscompiling: gox -osarch=\"darwin/amd64\" -osarch=\"linux/amd64\""
+if ! gox -osarch="darwin/amd64" -osarch="linux/amd64" >> $GOX_BUILD_LOG 2>&1; then
+    echo "FAILURE: gox command failed to build for deployment architecture"
+    echo "check gox_build.log for more info"
+fi
+

shortlink/slv0/generate.go

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+package main
+
+//REMOVE_TO_ENABLE go:generate stringer -type=EXAMPLE

shortlink/slv0/generate_tools.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+# if you are using modules you don't need this file
+
+# if not, this is a great place to note what third party modules you may need to get.
+
+go get -u golang.org/x/tools/cmd/stringer
+
+go get -u github.com/lib/pq

shortlink/slv0/main.go

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+package main
+
+import (
+	"flag"
+	"log"
+	"os"
+	"runtime"
+	"time"
+)
+
+var show_h bool
+var show_help bool
+var show_version bool
+
+func init() {
+	flag.BoolVar(&show_h, "h", false, "show help message and exit(0)")
+	flag.BoolVar(&show_help, "help", false, "show help message and exit(0)")
+	flag.BoolVar(&show_version, "version", false, "show version info and exit(0)")
+}
+
+func main() {
+	log.Println(current_function(), "entering")
+	defer trace(current_function(), time.Now())
+
+	log.Printf("Starting %v (v%v, build %v, build date:%v)", os.Args[0], Version(), BuildNumber(), BuildDate())
+	log.Printf("os.Args: %v", os.Args)
+	log.Printf("Go (runtime:%v) (GOMAXPROCS:%d) (NumCPUs:%d)\n", runtime.Version(), runtime.GOMAXPROCS(-1), runtime.NumCPU())
+
+	// command line flags:
+	flag.Parse()
+
+	if show_version {
+		os.Exit(0)
+	}
+
+	if show_h || show_help {
+		flag.Usage()
+		os.Exit(0)
+	}
+
+	log.Println("Hello Gophers!")
+}

shortlink/slv0/templates.go

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+package main
+
+// TODO

shortlink/slv0/util.go

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+package main
+
+import (
+	"log"
+	"runtime"
+	"time"
+)
+
+//
+// Usage example: copy paste the two lines to the beginning of any function
+// 	log.Println(current_function(), "entering")
+//	defer trace(current_function(), time.Now())
+func trace(function_name string, start_time time.Time) {
+	elapsed := time.Since(start_time)
+	log.Printf("%s exiting ~ %s elapsed", function_name, elapsed)
+}
+
+func current_function() string {
+	pc := make([]uintptr, 15)
+	n := runtime.Callers(2, pc)
+	frames := runtime.CallersFrames(pc[:n])
+	frame, _ := frames.Next()
+	return frame.Function
+}

shortlink/slv0/version.go

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+package main
+
+import (
+	"fmt"
+	"log"
+	"time"
+)
+
+const (
+	internal_BUILD_TIMESTAMP = 1500000000
+	internal_BUILD_NUMBER    = 0
+	internal_VERSION_STRING  = "0.0.0"
+)
+
+func BuildDate() time.Time {
+	return time.Unix(internal_BUILD_TIMESTAMP, 0)
+}
+func BuildNumber() int64 {
+	return internal_BUILD_NUMBER
+}
+func Version() string {
+	return internal_VERSION_STRING
+}
+
+func VersionInfo() string {
+	return fmt.Sprintf("shortlink (%v, build %v, build date:%v)", Version(), BuildNumber(), BuildDate())
+}
+
+func LogVersionInfo() {
+	log.Printf(VersionInfo())
+}

shortlink/slv0/version_bump.sh

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+#!/bin/sh
+
+# Last edit 2018-08-27
+
+set -o nounset
+set -o errexit
+
+# you can add the following lines to .git/hooks/pre-commit to auto bump build num:
+#
+# ./version_bump.sh
+# git add version.go
+
+VERSION_GO_FILENAME="version.go"
+
+usage(){
+  echo "Usage: $0 major|minor|patch|build"
+  echo "  $0 build (just update buildnum, default)"
+  echo "  $0 patch (1.0.PATCH)"
+  echo "  $0 minor (1.MINOR.0)"
+  echo "  $0 major (MAJOR.0.0)"
+}
+
+bump_build(){
+  CURRENT_BUILD_NUM=$(grep -o "internal_BUILD_NUMBER\\s*=\\s*[0-9]\\+" $VERSION_GO_FILENAME | grep -o "[0-9]\\+")
+  NEW_NUM=$((CURRENT_BUILD_NUM+1))
+  echo "Bumping build number, from ${CURRENT_BUILD_NUM} to $NEW_NUM"
+
+  sed -i.bak "s/internal_BUILD_NUMBER[[:space:]]*=[[:space:]]*[0-9]*/internal_BUILD_NUMBER\\ =\\ ${NEW_NUM}/g" $VERSION_GO_FILENAME
+
+
+  NEW_TS=$(date +%s)
+  echo "Bumping build timestamp new=$NEW_TS"
+
+  sed -i.bak "s/internal_BUILD_TIMESTAMP[[:space:]]*=[[:space:]]*[0-9][0-9]*/internal_BUILD_TIMESTAMP\\ =\\ ${NEW_TS}/g" $VERSION_GO_FILENAME
+
+  rm -f version.go.bak
+
+  # cleanup
+  go fmt version.go > /dev/null
+
+  FINAL_VERSION_STRING=$(grep -o "internal_VERSION_STRING\\s*=\\s\"[vV]*[0-9]*\.[0-9]*\.[0-9]*\"\\+" $VERSION_GO_FILENAME | grep -o "[0-9]*\.[0-9]*\.[0-9]*")
+  echo "v${FINAL_VERSION_STRING}"
+}
+
+bump_version_string(){
+  echo "Bumping ${POSITION} number, from ${XYZ_VERSION_STRING} to ${NEW_VERSION_STRING}"
+  sed -i.bak "s/internal_VERSION_STRING[[:space:]]*=[[:space:]]*\"[vV]*[0-9]*\.[0-9]*\.[0-9]*\"/internal_VERSION_STRING\\ =\\ \"${NEW_VERSION_STRING}\"/g" $VERSION_GO_FILENAME
+
+  bump_build
+}
+
+
+bump_patch(){
+  echo "patching"
+  NEW_PATCH_NUM=$((PATCH_NUM+1))
+  NEW_VERSION_STRING=${MAJOR_NUM}.${MINOR_NUM}.${NEW_PATCH_NUM}
+  bump_version_string
+}
+
+bump_minor(){
+  NEW_MINOR_NUM=$((MINOR_NUM+1))
+  NEW_PATCH_NUM="0"
+  NEW_VERSION_STRING=${MAJOR_NUM}.${NEW_MINOR_NUM}.${NEW_PATCH_NUM}
+  bump_version_string
+}
+
+bump_major(){
+  NEW_MAJOR_NUM=$((MAJOR_NUM+1))
+  NEW_MINOR_NUM="0"
+  NEW_PATCH_NUM="0"
+  NEW_VERSION_STRING=${NEW_MAJOR_NUM}.${NEW_MINOR_NUM}.${NEW_PATCH_NUM}
+  bump_version_string
+}
+
+tag(){
+  FINAL_VERSION_STRING=$(grep -o "internal_VERSION_STRING\\s*=\\s\"[vV]*[0-9]*\.[0-9]*\.[0-9]*\"\\+" $VERSION_GO_FILENAME | grep -o "[0-9]*\.[0-9]*\.[0-9]*")
+  git add version.go
+  git commit -m "tagging version v$FINAL_VERSION_STRING"
+  git tag v$FINAL_VERSION_STRING
+
+  echo "use the following command to push tag to origin:"
+  echo "git push && git push --tags"
+}
+
+
+
+if [ $# -eq 0 ]
+then
+  bump_build
+  exit 0
+elif [ $# -gt 1 ]
+then
+  echo "too many arguments supplied"
+  usage
+  exit 1
+fi
+
+
+while [ "$1" != "" ]; do
+
+  PARAM=`echo $1 | awk -F= '{print $1}'`
+  VALUE=`echo $1 | awk -F= '{print $2}'`
+
+  # should be of form x.y.z
+  XYZ_VERSION_STRING=$(grep -o "internal_VERSION_STRING\\s*=\\s\"[vV]*[0-9]*\.[0-9]*\.[0-9]*\"\\+" $VERSION_GO_FILENAME | grep -o "[0-9]*\.[0-9]*\.[0-9]*")
+
+  MAJOR_NUM=$(echo "$XYZ_VERSION_STRING" | cut -d '.' -f 1)
+  MINOR_NUM=$(echo "$XYZ_VERSION_STRING" | cut -d '.' -f 2)
+  PATCH_NUM=$(echo "$XYZ_VERSION_STRING" | cut -d '.' -f 3)
+
+  POSITION=$1
+
+  case $PARAM in
+      -h | --help)
+          usage
+          exit 0
+          ;;
+      build)
+        bump_build
+        exit 0
+        ;;
+      patch)
+        bump_patch
+        exit 0
+        ;;
+      minor)
+        bump_minor
+        exit 0
+        ;;
+      major)
+        bump_major
+        exit 0
+        ;;
+      tag)
+        tag
+        exit 0
+        ;;
+      *)
+          echo "ERROR: unknown parameter \"$PARAM\""
+          usage
+          exit 1
+          ;;
+  esac
+  shift
+done
+
+
+
+