feat(database): connect postgres via socket and read config from env _FILE secrets (#2061)

* feat(database): connect postgres via socket

* feat(config): read env var secrets from file

* docs: explain env var secrets

* refactor: generate postgres dsn

internal/database/postgres_test.go

@@ -0,0 +1,67 @@
+package database
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPostgresDSN(t *testing.T) {
+	type args struct {
+		host        string
+		port        int
+		user        string
+		pass        string
+		database    string
+		socket      string
+		sslMode     string
+		extraParams string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "default",
+			args: args{
+				host:     "localhost",
+				port:     5432,
+				user:     "postgres",
+				pass:     "PASSWORD",
+				database: "postgres",
+				sslMode:  "disable",
+				socket:   "",
+			},
+			want: "postgres://postgres:PASSWORD@localhost:5432/postgres?sslmode=disable",
+		},
+		{
+			name: "default",
+			args: args{
+				host:        "localhost",
+				port:        5432,
+				user:        "postgres",
+				pass:        "PASSWORD",
+				database:    "postgres",
+				sslMode:     "disable",
+				extraParams: "connect_timeout=10",
+				socket:      "",
+			},
+			want: "postgres://postgres:PASSWORD@localhost:5432/postgres?sslmode=disable&connect_timeout=10",
+		},
+		{
+			name: "default",
+			args: args{
+				database: "postgres",
+				socket:   "/path/to/socket",
+			},
+			want: "postgres://postgres?host=%2Fpath%2Fto%2Fsocket",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, _ := PostgresDSN(tt.args.host, tt.args.port, tt.args.user, tt.args.pass, tt.args.database, tt.args.socket, tt.args.sslMode, tt.args.extraParams)
+			assert.Equalf(t, tt.want, got, "PostgresDSN(%v, %v, %v, %v, %v, %v, %v, %v)", tt.args.host, tt.args.port, tt.args.user, tt.args.pass, tt.args.database, tt.args.socket, tt.args.sslMode, tt.args.extraParams)
+		})
+	}
+}