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-rw-r--r--srv/cfg/cfg.go200
-rw-r--r--srv/cfg/cfg_test.go46
2 files changed, 0 insertions, 246 deletions
diff --git a/srv/cfg/cfg.go b/srv/cfg/cfg.go
deleted file mode 100644
index 8513e16..0000000
--- a/srv/cfg/cfg.go
+++ /dev/null
@@ -1,200 +0,0 @@
-// Package cfg implements a simple wrapper around go's flag package, in order to
-// implement initialization hooks.
-package cfg
-
-import (
- "context"
- "flag"
- "fmt"
- "os"
- "strconv"
- "strings"
-)
-
-// Cfger is a component which can be used with Cfg to setup its initialization.
-type Cfger interface {
- SetupCfg(*Cfg)
-}
-
-// Params are used to initialize a Cfg instance.
-type Params struct {
-
- // Args are the command line arguments, excluding the command-name.
- //
- // Defaults to os.Args[1:]
- Args []string
-
- // Env is the process's environment variables.
- //
- // Defaults to the real environment variables.
- Env map[string]string
-
- // EnvPrefix indicates a string to prefix to all environment variable names
- // that Cfg will read. Will be automatically suffixed with a "_" if given.
- EnvPrefix string
-}
-
-func (p Params) withDefaults() Params {
-
- if p.Args == nil {
- p.Args = os.Args[1:]
- }
-
- if p.Env == nil {
-
- p.Env = map[string]string{}
-
- for _, envVar := range os.Environ() {
-
- parts := strings.SplitN(envVar, "=", 2)
-
- if len(parts) < 2 {
- panic(fmt.Sprintf("envVar %q returned from os.Environ() somehow", envVar))
- }
-
- p.Env[parts[0]] = parts[1]
- }
- }
-
- if p.EnvPrefix != "" {
- p.EnvPrefix = strings.TrimSuffix(p.EnvPrefix, "_") + "_"
- }
-
- return p
-}
-
-// Cfg is a wrapper around the stdlib's FlagSet and a set of initialization
-// hooks.
-type Cfg struct {
- params Params
- flagSet *flag.FlagSet
-
- hooks []func(ctx context.Context) error
-}
-
-// New initializes and returns a new instance of *Cfg.
-func New(params Params) *Cfg {
-
- params = params.withDefaults()
-
- return &Cfg{
- params: params,
- flagSet: flag.NewFlagSet("", flag.ExitOnError),
- }
-}
-
-// OnInit appends the given callback to the sequence of hooks which will run on
-// a call to Init.
-func (c *Cfg) OnInit(cb func(context.Context) error) {
- c.hooks = append(c.hooks, cb)
-}
-
-// Init runs all hooks registered using OnInit, in the same order OnInit was
-// called. If one returns an error that error is returned and no further hooks
-// are run.
-func (c *Cfg) Init(ctx context.Context) error {
- if err := c.flagSet.Parse(c.params.Args); err != nil {
- return err
- }
-
- for _, h := range c.hooks {
- if err := h(ctx); err != nil {
- return err
- }
- }
-
- return nil
-}
-
-func (c *Cfg) envifyName(name string) string {
- name = c.params.EnvPrefix + name
- name = strings.Replace(name, "-", "_", -1)
- name = strings.ToUpper(name)
- return name
-}
-
-func envifyUsage(envName, usage string) string {
- return fmt.Sprintf("%s (overrides %s)", usage, envName)
-}
-
-// StringVar is equivalent to flag.FlagSet's StringVar method, but will
-// additionally set up an environment variable for the parameter.
-func (c *Cfg) StringVar(p *string, name, value, usage string) {
-
- envName := c.envifyName(name)
-
- c.flagSet.StringVar(p, name, value, envifyUsage(envName, usage))
-
- if val := c.params.Env[envName]; val != "" {
- *p = val
- }
-}
-
-// String is equivalent to flag.FlagSet's String method, but will additionally
-// set up an environment variable for the parameter.
-func (c *Cfg) String(name, value, usage string) *string {
- p := new(string)
- c.StringVar(p, name, value, usage)
- return p
-}
-
-// IntVar is equivalent to flag.FlagSet's IntVar method, but will additionally
-// set up an environment variable for the parameter.
-func (c *Cfg) IntVar(p *int, name string, value int, usage string) {
-
- envName := c.envifyName(name)
-
- c.flagSet.IntVar(p, name, value, envifyUsage(envName, usage))
-
- // if we can't parse the envvar now then just hold onto the error until
- // Init, otherwise we'd have to panic here and that'd be ugly.
- var err error
-
- if valStr := c.params.Env[envName]; valStr != "" {
-
- var val int
- val, err = strconv.Atoi(valStr)
-
- if err != nil {
- err = fmt.Errorf(
- "parsing envvar %q with value %q: %w",
- envName, valStr, err,
- )
-
- } else {
- *p = val
- }
- }
-
- c.OnInit(func(context.Context) error { return err })
-}
-
-// Int is equivalent to flag.FlagSet's Int method, but will additionally set up
-// an environment variable for the parameter.
-func (c *Cfg) Int(name string, value int, usage string) *int {
- p := new(int)
- c.IntVar(p, name, value, usage)
- return p
-}
-
-// SubCmd should be called _after_ Init. Init will have consumed all arguments
-// up until the first non-flag argument. This non-flag argument is a
-// sub-command, and is returned by this method. This method also resets Cfg's
-// internal state so that new options can be added to it.
-//
-// If there is no sub-command following the initial set of flags then this will
-// return empty string.
-func (c *Cfg) SubCmd() string {
- c.params.Args = c.flagSet.Args()
- if len(c.params.Args) == 0 {
- return ""
- }
-
- subCmd := c.params.Args[0]
-
- c.flagSet = flag.NewFlagSet(subCmd, flag.ExitOnError)
- c.hooks = nil
- c.params.Args = c.params.Args[1:]
-
- return subCmd
-}
diff --git a/srv/cfg/cfg_test.go b/srv/cfg/cfg_test.go
deleted file mode 100644
index 7ccf94a..0000000
--- a/srv/cfg/cfg_test.go
+++ /dev/null
@@ -1,46 +0,0 @@
-package cfg
-
-import (
- "context"
- "testing"
-
- "github.com/stretchr/testify/assert"
-)
-
-func TestStringVar(t *testing.T) {
-
- cfg := New(Params{
- Args: []string{"--foo=CLI"},
- Env: map[string]string{"FOO": "ENV", "BAR": "ENV"},
- })
-
- var foo, bar, baz string
-
- cfg.StringVar(&foo, "foo", "DEF", "")
- cfg.StringVar(&bar, "bar", "DEF", "")
- cfg.StringVar(&baz, "baz", "DEF", "")
-
- assert.NoError(t, cfg.Init(context.Background()))
- assert.Equal(t, "CLI", foo)
- assert.Equal(t, "ENV", bar)
- assert.Equal(t, "DEF", baz)
-}
-
-func TestIntVar(t *testing.T) {
-
- cfg := New(Params{
- Args: []string{"--foo=111"},
- Env: map[string]string{"FOO": "222", "BAR": "222"},
- })
-
- var foo, bar, baz int
-
- cfg.IntVar(&foo, "foo", 333, "")
- cfg.IntVar(&bar, "bar", 333, "")
- cfg.IntVar(&baz, "baz", 333, "")
-
- assert.NoError(t, cfg.Init(context.Background()))
- assert.Equal(t, 111, foo)
- assert.Equal(t, 222, bar)
- assert.Equal(t, 333, baz)
-}