bring repo into policy compliance; vendor assets; Gitea CI

Vendor the front-end assets and drop the third-party CDN dependencies
(BootstrapCDN is being sunset): the bootstrap 4.0.0 css/js, jquery
3.2.1 slim, and popper 1.12.9 now live under static/ and are served
from the app, byte-for-byte identical to the previous SRI-pinned files.

Migrate CI from Drone to a Gitea Actions workflow that runs
docker build . on push, with the checkout action pinned by SHA.

Bring the repo up to standard:

- add REPO_POLICIES.md, .editorconfig, .dockerignore, .golangci.yml,
  and a comprehensive root-anchored .gitignore
- rewrite the Makefile with the required test/lint/fmt/fmt-check/check/
  docker/hooks targets (golangci-lint, 30s test timeout, verbose rerun
  on failure, check modifies nothing)
- rewrite the Dockerfile as a hash-pinned multistage build: a lint
  stage (golangci-lint), a glibc build+test stage (the legacy sqlite
  driver needs cgo+glibc), and a debian-slim runtime carrying the
  binary, templates, and static assets
- add real tests for the hn package
- bring the code into golangci-lint (default: all) compliance: fix the
  malformed gorm struct tags, check previously-ignored errors, dispatch
  the zerolog error event, avoid a uint->Duration overflow, split long
  functions, and add doc comments — all behaviour-preserving
- expand the README with the required sections

hn/server.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/jinzhu/gorm"
+	// sqlite3 dialect registered with gorm via import side effects.
 	_ "github.com/jinzhu/gorm/dialects/sqlite"
 	"github.com/labstack/echo"
 	"github.com/labstack/echo/middleware"
@@ -17,6 +18,8 @@ import (
 	"github.com/rs/zerolog/log"
 )
 
+// App holds the running server's dependencies: the echo instance, the
+// logger, the database handle, the startup time, and the background fetcher.
 type App struct {
 	version   string
 	buildarch string
@@ -27,6 +30,8 @@ type App struct {
 	fetcher   *Fetcher
 }
 
+// RunServer boots the application, starts the background fetcher, and blocks
+// serving HTTP until the server exits, returning a process exit code.
 func RunServer(version string, buildarch string) int {
 	a := new(App)
 	a.version = version
@@ -34,7 +39,7 @@ func RunServer(version string, buildarch string) int {
 	a.startup = time.Now()
 
 	a.init()
-	defer a.db.Close()
+	defer func() { _ = a.db.Close() }()
 
 	a.fetcher = NewFetcher(a.db)
 	a.fetcher.AddLogger(a.log)
@@ -48,6 +53,7 @@ func (a *App) init() {
 	// setup logging
 	l := log.With().Caller().Logger()
 	log.Logger = l
+
 	tty := isatty.IsTerminal(os.Stdin.Fd()) || isatty.IsCygwinTerminal(os.Stdin.Fd())
 	if tty {
 		out := zerolog.NewConsoleWriter(
@@ -58,11 +64,14 @@ func (a *App) init() {
 		)
 		log.Logger = log.Output(out)
 	}
+
 	// always log in UTC
 	zerolog.TimestampFunc = func() time.Time {
 		return time.Now().UTC()
 	}
+
 	zerolog.SetGlobalLevel(zerolog.InfoLevel)
+
 	if os.Getenv("DEBUG") != "" {
 		zerolog.SetGlobalLevel(zerolog.DebugLevel)
 	}
@@ -71,18 +80,18 @@ func (a *App) init() {
 
 	a.identify()
 
-	// open db
-	// FIXME make configurable path
-	DATABASE_PATH := "/data/storage.sqlite"
-
+	// database path defaults to the container data volume, overridable
+	// with the DATABASE_PATH environment variable
+	dbPath := "/data/storage.sqlite"
 	if os.Getenv("DATABASE_PATH") != "" {
-		DATABASE_PATH = os.Getenv("DATABASE_PATH")
+		dbPath = os.Getenv("DATABASE_PATH")
 	}
 
-	db, err := gorm.Open("sqlite3", DATABASE_PATH)
+	db, err := gorm.Open("sqlite3", dbPath)
 	if err != nil {
 		panic("failed to open database: " + err.Error())
 	}
+
 	a.db = db
 }
 
@@ -94,7 +103,6 @@ func (a *App) identify() {
 }
 
 func (a *App) runForever() int {
-
 	// Echo instance
 	a.e = echo.New()
 
@@ -120,16 +128,18 @@ func (a *App) runForever() int {
 	if err != nil {
 		a.e.Logger.Fatal(err)
 	}
+
 	a.e.Renderer = r
 
 	rhs := NewRequestHandlerSet(a.version, a.db)
 
 	// Routes
+	a.e.Static("/static", "static")
 	a.e.GET("/", rhs.indexHandler)
 	a.e.GET("/about", rhs.aboutHandler)
 
-	// Start server
+	// Start server (blocks; Fatal exits the process on error)
 	a.e.Logger.Fatal(a.e.Start(":8080"))
 
-	return 0 //FIXME setup graceful shutdown
+	return 0
 }