81 lines
2.3 KiB
Go
81 lines
2.3 KiB
Go
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package config
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import (
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"fmt"
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"strconv"
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"time"
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)
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// AppKey describes one application-configuration key: instance-global,
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// stored (as an override) in the DB `config` table, read once at startup.
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// Cold -- a changed value applies on the next backend restart.
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type AppKey struct {
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Key string
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Default string
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Description string
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Validate func(value string) error
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}
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// KeySessionDuration is the session cookie lifetime, in integer hours.
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const KeySessionDuration = "session.duration"
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var appRegistry = []AppKey{
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{
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Key: KeySessionDuration,
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Default: "720",
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Description: "Session cookie lifetime in hours",
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Validate: validatePositiveInt,
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},
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}
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// AppRegistry returns every known application-configuration key, in
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// display order.
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func AppRegistry() []AppKey { return appRegistry }
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func validatePositiveInt(v string) error {
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n, err := strconv.Atoi(v)
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if err != nil || n <= 0 {
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return fmt.Errorf("must be a positive integer, got %q", v)
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}
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return nil
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}
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// ValidateAppValue rejects unknown keys and invalid values -- every write
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// path's guard, so the config table can never accumulate junk.
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func ValidateAppValue(key, value string) error {
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for _, k := range appRegistry {
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if k.Key == key {
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if err := k.Validate(value); err != nil {
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return fmt.Errorf("%s: %w", key, err)
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}
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return nil
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}
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}
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return fmt.Errorf("unknown configuration key %q", key)
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}
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// AppConfig is the typed result of merging DB overrides over registry
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// defaults.
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type AppConfig struct {
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SessionDuration time.Duration
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}
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// LoadApp merges overrides (store.ConfigValues' map) over defaults. Pure
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// -- it takes the raw map instead of a *store.DB so this package needs no
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// store dependency and the merge logic tests without a database. A bad
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// stored value fails fast, same posture as Load() for env vars.
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func LoadApp(overrides map[string]string) (AppConfig, error) {
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merged := map[string]string{}
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for _, k := range appRegistry {
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merged[k.Key] = k.Default
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}
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for key, value := range overrides {
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if err := ValidateAppValue(key, value); err != nil {
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return AppConfig{}, fmt.Errorf("app config: %w", err)
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}
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merged[key] = value
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}
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hours, _ := strconv.Atoi(merged[KeySessionDuration])
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return AppConfig{SessionDuration: time.Duration(hours) * time.Hour}, nil
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}
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