[chore] Global server configuration overhaul (#575)

* move config flag names and usage to config package, rewrite config package to use global Configuration{} struct

Signed-off-by: kim <grufwub@gmail.com>

* improved code comment

Signed-off-by: kim <grufwub@gmail.com>

* linter

Signed-off-by: kim <grufwub@gmail.com>

* fix unmarshaling

Signed-off-by: kim <grufwub@gmail.com>

* remove kim's custom go compiler changes

Signed-off-by: kim <grufwub@gmail.com>

* generate setter and flag-name functions, implement these in codebase

Signed-off-by: kim <grufwub@gmail.com>

* update deps

Signed-off-by: kim <grufwub@gmail.com>

* small change

Signed-off-by: kim <grufwub@gmail.com>

* appease the linter...

Signed-off-by: kim <grufwub@gmail.com>

* move configuration into ConfigState structure, ensure reloading to/from viper settings to keep in sync

Signed-off-by: kim <grufwub@gmail.com>

* lint

Signed-off-by: kim <grufwub@gmail.com>

* update code comments

Signed-off-by: kim <grufwub@gmail.com>

* fix merge issue

Signed-off-by: kim <grufwub@gmail.com>

* fix merge issue

Signed-off-by: kim <grufwub@gmail.com>

* improved version string (removes time + go version)

Signed-off-by: kim <grufwub@gmail.com>

* fix version string build to pass test script + consolidate logic in func

Signed-off-by: kim <grufwub@gmail.com>

* add license text, update config.Defaults comment

Signed-off-by: kim <grufwub@gmail.com>

* add license text to generated config helpers file

Signed-off-by: kim <grufwub@gmail.com>

* defer unlock on config.Set___(), to ensure unlocked on panic

Signed-off-by: kim <grufwub@gmail.com>

* make it more obvious which cmd flags are being attached

Signed-off-by: kim <grufwub@gmail.com>

1 files changed, 112 insertions, 0 deletions

diff --git a/internal/config/gen/gen.go b/internal/config/gen/gen.go
new file mode 100644
index 000000000..d36fee0e9
--- /dev/null
+++ b/internal/config/gen/gen.go
@@ -0,0 +1,112 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"reflect"
+
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+)
+
+const license = `/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+`
+
+func main() {
+	var (
+		out string
+		gen string
+	)
+
+	// Load runtime config flags
+	flag.StringVar(&out, "out", "", "Generated file output path")
+	flag.StringVar(&gen, "gen", "helpers", "Type of file to generate (helpers)")
+	flag.Parse()
+
+	// Open output file path
+	output, err := os.OpenFile(out, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0o644)
+	if err != nil {
+		panic(err)
+	}
+
+	switch gen {
+	// Generate config field helper methods
+	case "helpers":
+		fmt.Fprint(output, "// THIS IS A GENERATED FILE, DO NOT EDIT BY HAND\n")
+		fmt.Fprint(output, license)
+		fmt.Fprint(output, "package config\n\n")
+		t := reflect.TypeOf(config.Configuration{})
+		for i := 0; i < t.NumField(); i++ {
+			field := t.Field(i)
+
+			// ConfigState structure helper methods
+			fmt.Fprintf(output, "// Get%s safely fetches the Configuration value for state's '%s' field\n", field.Name, field.Name)
+			fmt.Fprintf(output, "func (st *ConfigState) Get%s() (v %s) {\n", field.Name, field.Type.String())
+			fmt.Fprintf(output, "\tst.mutex.Lock()\n")
+			fmt.Fprintf(output, "\tv = st.config.%s\n", field.Name)
+			fmt.Fprintf(output, "\tst.mutex.Unlock()\n")
+			fmt.Fprintf(output, "\treturn\n")
+			fmt.Fprintf(output, "}\n\n")
+			fmt.Fprintf(output, "// Set%s safely sets the Configuration value for state's '%s' field\n", field.Name, field.Name)
+			fmt.Fprintf(output, "func (st *ConfigState) Set%s(v %s) {\n", field.Name, field.Type.String())
+			fmt.Fprintf(output, "\tst.mutex.Lock()\n")
+			fmt.Fprintf(output, "\tdefer st.mutex.Unlock()\n")
+			fmt.Fprintf(output, "\tst.config.%s = v\n", field.Name)
+			fmt.Fprintf(output, "\tst.reloadToViper()\n")
+			fmt.Fprintf(output, "}\n\n")
+
+			// Global ConfigState helper methods
+			// TODO: remove when we pass around a ConfigState{}
+			fmt.Fprintf(output, "// %sFlag returns the flag name for the '%s' field\n", field.Name, field.Name)
+			fmt.Fprintf(output, "func %sFlag() string { return \"%s\" }\n\n", field.Name, field.Tag.Get("name"))
+			fmt.Fprintf(output, "// Get%s safely fetches the value for global configuration '%s' field\n", field.Name, field.Name)
+			fmt.Fprintf(output, "func Get%[1]s() %[2]s { return global.Get%[1]s() }\n\n", field.Name, field.Type.String())
+			fmt.Fprintf(output, "// Set%s safely sets the value for global configuration '%s' field\n", field.Name, field.Name)
+			fmt.Fprintf(output, "func Set%[1]s(v %[2]s) { global.Set%[1]s(v) }\n\n", field.Name, field.Type.String())
+		}
+		_ = output.Close()
+		_ = exec.Command("gofmt", "-w", out).Run()
+
+	// The plain here is that eventually we might be able
+	// to generate an example configuration from struct tags
+
+	// Unknown type
+	default:
+		panic("unknown generation type: " + gen)
+	}
+}