Add config loader with strict stdlib-only TOML subset parser

Parse keyproxy.toml (listen address, [auth] token_ref, and the mpk-<name> ref map) using a deliberate TOML subset implemented with the standard library only. The surface is strict: unknown keys, malformed refs, and backend-specific misconfigurations (e.g. env refs setting key, file refs missing key) fail loudly at startup. The bearer-token ref must resolve through the file backend. Parse errors carry line numbers, never line contents. 💘 Generated with Crush Assisted-by: Crush:glm-5.2
2026-08-28 22:30:50 -05:00
parent b43bc55963
commit 7bec2a1905
4 changed files with 705 additions and 0 deletions
@@ -0,0 +1,97 @@
+package config
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseTOML(t *testing.T) {
+	tests := []struct {
+		name    string
+		in      string
+		want    map[string]any // dotted paths -> expected values
+		wantErr string
+	}{
+		{
+			name: "scalars and comments",
+			in:   "# top\nlisten = \"127.0.0.1:8082\" # inline\nflag = true\nnum = 42\n",
+			want: map[string]any{"listen": "127.0.0.1:8082", "flag": true, "num": int64(42)},
+		},
+		{
+			name: "tables with quoted dotted keys",
+			in:   "[refs.\"mpk-redmine\"]\nbackend = \"file\"\n\n[refs.\"mpk-env\"]\nbackend = \"env\"\n",
+			want: map[string]any{"refs.mpk-redmine.backend": "file", "refs.mpk-env.backend": "env"},
+		},
+		{
+			name: "escapes in basic strings",
+			in:   "a = \"x\\ty\\\"z\"\n",
+			want: map[string]any{"a": "x\ty\"z"},
+		},
+		{
+			name: "literal strings keep backslashes",
+			in:   "a = 'C:\\path'\n",
+			want: map[string]any{"a": `C:\path`},
+		},
+		{
+			name:    "duplicate key",
+			in:      "a = \"1\"\na = \"2\"\n",
+			wantErr: "duplicate key",
+		},
+		{
+			name:    "unterminated string",
+			in:      "a = \"oops\n",
+			wantErr: "unterminated string",
+		},
+		{
+			name:    "unsupported richer syntax fails loudly",
+			in:      "a = [\"x\", \"y\"]\n",
+			wantErr: "unsupported value",
+		},
+		{
+			name:    "malformed table header",
+			in:      "[refs\n",
+			wantErr: "malformed table header",
+		},
+		{
+			name:    "bare line without equals",
+			in:      "garbage\n",
+			wantErr: "expected key = value",
+		},
+		{
+			name:    "table conflicts with scalar",
+			in:      "refs = \"x\"\n[refs.\"mpk-a\"]\nbackend = \"file\"\n",
+			wantErr: "conflicts",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			doc, err := parseTOML([]byte(tt.in))
+			if tt.wantErr != "" {
+				if err == nil {
+					t.Fatalf("want error %q, got doc %v", tt.wantErr, doc)
+				}
+				if !strings.Contains(err.Error(), tt.wantErr) {
+					t.Fatalf("error %q does not contain %q", err, tt.wantErr)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			for path, want := range tt.want {
+				segs := strings.Split(path, ".")
+				cur := any(doc)
+				for _, seg := range segs {
+					m, ok := cur.(Doc)
+					if !ok {
+						t.Fatalf("path %s: %v is not a table", path, cur)
+					}
+					cur = m[seg]
+				}
+				if cur != want {
+					t.Fatalf("path %s: got %#v, want %#v", path, cur, want)
+				}
+			}
+		})
+	}
+}