From 03b19df115ed0c456cd5fa56bcd092d590a9f8f5 Mon Sep 17 00:00:00 2001
From: Brian Picciano <me@mediocregopher.com>
Date: Mon, 16 Dec 2024 12:19:48 +0100
Subject: [PATCH] Implement 'vpn public-address' subcommands

---
 go/cmd/entrypoint/vpn.go             |  1 +
 go/cmd/entrypoint/vpn_public_addr.go | 93 ++++++++++++++++++++++++++++
 tasks/soon/code/set-config-cas.md    |  8 +++
 tasks/v0.0.3/code/public-addr.md     |  7 ---
 4 files changed, 102 insertions(+), 7 deletions(-)
 create mode 100644 go/cmd/entrypoint/vpn_public_addr.go
 create mode 100644 tasks/soon/code/set-config-cas.md
 delete mode 100644 tasks/v0.0.3/code/public-addr.md

diff --git a/go/cmd/entrypoint/vpn.go b/go/cmd/entrypoint/vpn.go
index 9d25694..75e27af 100644
--- a/go/cmd/entrypoint/vpn.go
+++ b/go/cmd/entrypoint/vpn.go
@@ -70,6 +70,7 @@ var subCmdVPN = subCmd{
 		return ctx.doSubCmd(
 			subCmdVPNCreateCert,
 			subCmdVPNFirewall,
+			subCmdVPNPublicAddress,
 		)
 	},
 }
diff --git a/go/cmd/entrypoint/vpn_public_addr.go b/go/cmd/entrypoint/vpn_public_addr.go
new file mode 100644
index 0000000..d51d357
--- /dev/null
+++ b/go/cmd/entrypoint/vpn_public_addr.go
@@ -0,0 +1,93 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"net"
+)
+
+var subCmdVPNPublicAddressGet = subCmd{
+	name:  "get",
+	descr: "Display the currently configured public address",
+	do: doWithOutput(func(ctx subCmdCtx) (any, error) {
+		ctx, err := ctx.withParsedFlags(nil)
+		if err != nil {
+			return nil, fmt.Errorf("parsing flags: %w", err)
+		}
+
+		config, err := ctx.daemonRPC.GetConfig(ctx)
+		if err != nil {
+			return nil, fmt.Errorf("getting network config: %w", err)
+		}
+
+		if config.VPN.PublicAddr == "" {
+			return nil, errors.New("No public address configured")
+		}
+
+		return config.VPN.PublicAddr, nil
+	}),
+}
+
+var subCmdVPNPublicAddressSet = subCmd{
+	name:  "set",
+	descr: "Set the public address of the host, or overwrite the already configured one",
+	do: func(ctx subCmdCtx) error {
+		publicAddr := ctx.flags.String(
+			"public-addr",
+			"",
+			"Public address (host:port) that this host is publicly available on",
+		)
+
+		ctx, err := ctx.withParsedFlags(nil)
+		if err != nil {
+			return fmt.Errorf("parsing flags: %w", err)
+		}
+
+		if *publicAddr == "" {
+			return errors.New("--public-addr is required")
+		} else if _, _, err := net.SplitHostPort(*publicAddr); err != nil {
+			return fmt.Errorf("invalid --public-addr: %w", err)
+		}
+
+		config, err := ctx.daemonRPC.GetConfig(ctx)
+		if err != nil {
+			return fmt.Errorf("getting network config: %w", err)
+		}
+
+		config.VPN.PublicAddr = *publicAddr
+
+		return ctx.daemonRPC.SetConfig(ctx, config)
+	},
+}
+
+var subCmdVPNPublicAddressUnset = subCmd{
+	name:  "unset",
+	descr: "Unset the public address",
+	do: func(ctx subCmdCtx) error {
+		ctx, err := ctx.withParsedFlags(nil)
+		if err != nil {
+			return fmt.Errorf("parsing flags: %w", err)
+		}
+
+		config, err := ctx.daemonRPC.GetConfig(ctx)
+		if err != nil {
+			return fmt.Errorf("getting network config: %w", err)
+		}
+
+		config.VPN.PublicAddr = ""
+
+		return ctx.daemonRPC.SetConfig(ctx, config)
+	},
+}
+
+var subCmdVPNPublicAddress = subCmd{
+	name:  "public-address",
+	descr: "Configure the public address of this host, allowing other hosts to use it in order to find and communicate directly with each other",
+	do: func(ctx subCmdCtx) error {
+		return ctx.doSubCmd(
+			subCmdVPNPublicAddressGet,
+			subCmdVPNPublicAddressSet,
+			subCmdVPNPublicAddressUnset,
+		)
+	},
+}
diff --git a/tasks/soon/code/set-config-cas.md b/tasks/soon/code/set-config-cas.md
new file mode 100644
index 0000000..9b89ca4
--- /dev/null
+++ b/tasks/soon/code/set-config-cas.md
@@ -0,0 +1,8 @@
+---
+type: task
+---
+
+# Add a Compare-and-Swap mechanism to SetConfig
+
+This way we can avoid having issues if two different callers are doing a
+GetConfig-then-SetConfig.
diff --git a/tasks/v0.0.3/code/public-addr.md b/tasks/v0.0.3/code/public-addr.md
deleted file mode 100644
index e4f476b..0000000
--- a/tasks/v0.0.3/code/public-addr.md
+++ /dev/null
@@ -1,7 +0,0 @@
----
-type: task
----
-
-# Add `vpn public-addr set`, and `get` Sub-Commands.
-
-`get` should return an error if no public address is set.