6 files changed, 199 insertions(+), 0 deletions(-)

A LICENSE
A README.md
A go.mod
A go.sum
A main.go
A srp.go

@@ 1,13 @@
+Copyright 2020 Evan Tann
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.

@@ 1,62 @@
+# inventory2config
+
+Takes an inventory.json and a service-based SRP config file as inputs and
+outputs an SRP config file pointing at specific IPs.
+
+Example inventory.json:
+
+```json
+{"10.128.0.1":["my-app"]}
+```
+
+Example service-based SRP config file:
+
+```json
+{
+	"Services": {
+		"www.example.com": {
+			"HealthPath": "/health",
+			"Service": "my-app",
+			"Port": 3000
+		},
+		"www-example.internal": {
+			"HealthPath": "/health",
+			"Service": "my-app",
+			"Port": 3001
+		}
+	}
+}
+```
+
+To use:
+
+```bash
+inventory2config -i inventory.json -s config.json > config.json
+```
+
+This outputs a config.json with backends populated with the correct ip:port
+combinations like so:
+
+```json
+{
+	"Services": {
+		"www.example.com": {
+			"HealthPath": "/health",
+			"Service": "my-app",
+			"Port": 3000,
+			"Backends": ["10.128.0.1:3000"]
+		},
+		"www-example.internal": {
+			"HealthPath": "/health",
+			"Service": "my-app",
+			"Port": 3001,
+			"Backends": ["10.128.0.1:3001"]
+		}
+	}
+}
+```
+
+SRP will ignore the Service and Port. They are added for this tool only.
+
+In the event of an error, inventory2json will still output the original file to
+stdout, so no data is lost.

@@ 1,5 @@
+module git.sr.ht/~egtann/inventory2config
+
+go 1.14
+
+require git.sr.ht/~egtann/up v0.0.0-20200324172709-10f0fb584d43

@@ 1,2 @@
+git.sr.ht/~egtann/up v0.0.0-20200324172709-10f0fb584d43 h1:0dsb/Oivfxhd0HDxbIx5SzefqcaYeqL+TWihyNMaLsk=
+git.sr.ht/~egtann/up v0.0.0-20200324172709-10f0fb584d43/go.mod h1:z51L8eNGLPT0f3d/+8danxnrOmuXRh4Ca9HcviG2D0M=

@@ 1,97 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"git.sr.ht/~egtann/up"
+)
+
+func main() {
+	// Always send to stdout our new SRP or the original version
+	srpOut, err := run()
+	fmt.Printf(srpOut)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run() (string, error) {
+	// Read an inventory file and an SRP config file
+	var (
+		invFile = flag.String("i", "inventory.json", "inventory file")
+		srpFile = flag.String("s", "config.json", "srp config file")
+	)
+	flag.Parse()
+
+	srpByt, err := ioutil.ReadFile(*srpFile)
+	if err != nil {
+		return "", fmt.Errorf("read srp config: %w", err)
+	}
+	origSRP := string(srpByt)
+	conf := srpConfig{}
+	if err = json.Unmarshal(srpByt, &conf); err != nil {
+		return origSRP, fmt.Errorf("decode srp config: %w", err)
+	}
+
+	inventory, err := parseInventory(*invFile)
+	if err != nil {
+		return origSRP, fmt.Errorf("parse inventory: %w", err)
+	}
+
+	// Gee willikers, Batman, this is O(N^3)
+	for ip, serviceNames := range inventory {
+	middle:
+		for _, name := range serviceNames {
+			for _, backend := range conf.Services {
+				if backend.Service != name {
+					continue
+				}
+				if ip == "" {
+					continue
+				}
+				ipPort := fmt.Sprintf("%s:%d", ip, backend.Port)
+				if backend.Port == 0 {
+					ipPort = ip
+				}
+				backend.Backends = append(backend.Backends, ipPort)
+				conf.Services[name] = backend
+				break middle
+			}
+		}
+	}
+
+	buf := &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	enc.SetIndent("", "\t")
+	if err := enc.Encode(conf); err != nil {
+		return origSRP, fmt.Errorf("encode config: %w", err)
+	}
+
+	// TODO(egtann) output the original config via stdout if any error
+	// happens.
+	//
+	// TODO(egtann) on success, output the config formatted for human
+	// editing (i.e. prettify)
+
+	return string(buf.Bytes()), nil
+}
+
+func parseInventory(filename string) (up.Inventory, error) {
+	fi, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = fi.Close() }()
+
+	inv := up.Inventory{}
+	if err = json.NewDecoder(fi).Decode(&inv); err != nil {
+		return nil, fmt.Errorf("decode: %w", err)
+	}
+	return inv, nil
+}

@@ 1,20 @@
+package main
+
+type srpConfig struct {
+	Services map[string]*backend
+	API      struct{ Subnet string }
+}
+
+type backend struct {
+	HealthPath string    `json:",omitempty"`
+	Backends   []string  `json:",omitempty"`
+	Redirect   *redirect `json:",omitempty"`
+	Service    string    `json:",omitempty"`
+	Port       int       `json:",omitempty"`
+}
+
+type redirect struct {
+	URL         string `json:",omitempty"`
+	Permanent   bool   `json:",omitempty"`
+	DiscardPath bool   `json:",omitempty"`
+}