new flag: --connect-to

Allows user to override DNS for the initial config request. This is
accomplished using a custom DialContext overring the hostname used to
Dial to. This allows for TLS certificate validation to still
happen(optionally) while connecting to TLS secured resources.

Also,
    - allows for optional enforcement of certificate verification
    - stamp built git version into binary and adds a --version option
    - adds a user-agent to all outgoing request
    - exit(1) on failures for easier shell error detection

1 files changed, 46 insertions, 0 deletions

diff --git a/utilities/transport.go b/utilities/transport.go
new file mode 100644
index 0000000..2d70989
--- /dev/null
+++ b/utilities/transport.go
@@ -0,0 +1,46 @@
+/*
+ * This file is part of Go Responsiveness.
+ *
+ * Go Responsiveness is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software Foundation,
+ * either version 2 of the License, or (at your option) any later version.
+ * Go Responsiveness is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with Go Responsiveness. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package utilities
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"time"
+
+	"golang.org/x/net/http2"
+)
+
+func OverrideHostTransport(transport *http.Transport, connectToAddr string) {
+	dialer := &net.Dialer{
+		Timeout: 10 * time.Second,
+	}
+
+	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+		_, port, err := net.SplitHostPort(addr)
+		if err != nil {
+			return nil, err
+		}
+
+		if len(connectToAddr) > 0 {
+			addr = net.JoinHostPort(connectToAddr, port)
+		}
+
+		return dialer.DialContext(ctx, network, addr)
+	}
+
+	http2.ConfigureTransport(transport)
+
+}