feat: add releases.conf files and installerconf parser

Simple key=value config per package declaring the fetch source and
its parameters. Greppable, no dependencies needed to parse.

  grep 'source = github' */releases.conf
  grep 'owner = therootcompany' */releases.conf

70 packages configured. installerconf package provides the reader.
fetchraw will be updated to read these instead of a hardcoded list.

internal/installerconf/installerconf.go

@@ -0,0 +1,58 @@
+// Package installerconf reads per-package releases.conf files.
+//
+// The format is simple key=value, one per line. Blank lines and lines
+// starting with # are ignored. Keys and values are trimmed of whitespace.
+//
+//	source = github
+//	owner = gohugoio
+//	repo = hugo
+package installerconf
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+// Conf holds the parsed contents of a releases.conf file.
+type Conf struct {
+	m map[string]string
+}
+
+// Read parses a releases.conf file.
+func Read(path string) (*Conf, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("installerconf: %w", err)
+	}
+	defer f.Close()
+
+	c := &Conf{m: make(map[string]string)}
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || line[0] == '#' {
+			continue
+		}
+		key, val, ok := strings.Cut(line, "=")
+		if !ok {
+			continue
+		}
+		c.m[strings.TrimSpace(key)] = strings.TrimSpace(val)
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("installerconf: read %s: %w", path, err)
+	}
+	return c, nil
+}
+
+// Get returns the value for a key, or "" if not set.
+func (c *Conf) Get(key string) string {
+	return c.m[key]
+}
+
+// Source returns the fetch source type (e.g. "github", "nodedist", "gitea").
+func (c *Conf) Source() string {
+	return c.m["source"]
+}

internal/installerconf/installerconf_test.go

@@ -0,0 +1,113 @@
+package installerconf_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/webinstall/webi-installers/internal/installerconf"
+)
+
+func TestRead(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "releases.conf")
+	os.WriteFile(path, []byte(`
+# Hugo release config
+source = github
+owner = gohugoio
+repo = hugo
+`), 0o644)
+
+	c, err := installerconf.Read(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Source() != "github" {
+		t.Errorf("Source() = %q, want github", c.Source())
+	}
+	if c.Get("owner") != "gohugoio" {
+		t.Errorf("owner = %q, want gohugoio", c.Get("owner"))
+	}
+	if c.Get("repo") != "hugo" {
+		t.Errorf("repo = %q, want hugo", c.Get("repo"))
+	}
+}
+
+func TestReadMonorepo(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "releases.conf")
+	os.WriteFile(path, []byte(`source = github
+owner = therootcompany
+repo = golib
+tag_prefix = tools/monorel/
+`), 0o644)
+
+	c, err := installerconf.Read(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Get("tag_prefix") != "tools/monorel/" {
+		t.Errorf("tag_prefix = %q", c.Get("tag_prefix"))
+	}
+}
+
+func TestReadNodeDist(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "releases.conf")
+	os.WriteFile(path, []byte(`source = nodedist
+url = https://nodejs.org/download/release
+`), 0o644)
+
+	c, err := installerconf.Read(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Source() != "nodedist" {
+		t.Errorf("Source() = %q, want nodedist", c.Source())
+	}
+	if c.Get("url") != "https://nodejs.org/download/release" {
+		t.Errorf("url = %q", c.Get("url"))
+	}
+}
+
+func TestReadSkipsBlanksAndComments(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "releases.conf")
+	os.WriteFile(path, []byte(`
+# comment
+source = github
+
+# another comment
+owner = foo
+`), 0o644)
+
+	c, err := installerconf.Read(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Source() != "github" {
+		t.Errorf("Source() = %q", c.Source())
+	}
+	if c.Get("owner") != "foo" {
+		t.Errorf("owner = %q", c.Get("owner"))
+	}
+}
+
+func TestGetMissing(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "releases.conf")
+	os.WriteFile(path, []byte("source = github\n"), 0o644)
+
+	c, err := installerconf.Read(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c.Get("nonexistent") != "" {
+		t.Errorf("Get(nonexistent) = %q, want empty", c.Get("nonexistent"))
+	}
+}