mirror of
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85 lines
2.2 KiB
Go
85 lines
2.2 KiB
Go
package config
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import (
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"context"
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"fmt"
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"os"
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"time"
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"github.com/neilotoole/sq/libsq/core/errz"
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"github.com/neilotoole/sq/libsq/core/ioz/lockfile"
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"github.com/neilotoole/sq/libsq/core/options"
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)
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// Store saves and loads config.
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type Store interface {
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// Exists returns true if the config exists in the store.
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Exists() bool
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// Save writes config to the store.
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Save(ctx context.Context, cfg *Config) error
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// Load reads config from the store.
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Load(ctx context.Context) (*Config, error)
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// Location returns the location of the store, typically
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// a file path.
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Location() string
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// Lockfile returns the lockfile used by the store, but does not acquire
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// the lock, which is the caller's responsibility. The lock should always
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// be acquired before mutating config. It is also the caller's responsibility
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// to release the acquired lock when done.
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Lockfile() (lockfile.Lockfile, error)
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}
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// DiscardStore implements Store but its Save method is no-op
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// and Load always returns a new empty Config. Useful for testing.
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type DiscardStore struct{}
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// Exists implements Store.Exists. It returns true.
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func (s DiscardStore) Exists() bool {
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return true
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}
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// Lockfile implements Store.Lockfile.
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func (DiscardStore) Lockfile() (lockfile.Lockfile, error) {
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f, err := os.CreateTemp("", fmt.Sprintf("sq-%d.lock", os.Getpid()))
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if err != nil {
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return "", errz.Err(err)
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}
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fname := f.Name()
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if err = f.Close(); err != nil {
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return "", errz.Err(err)
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}
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return lockfile.Lockfile(fname), nil
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}
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var _ Store = (*DiscardStore)(nil)
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// Load returns a new empty Config.
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func (DiscardStore) Load(context.Context) (*Config, error) {
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return New(), nil
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}
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// Save is no-op.
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func (DiscardStore) Save(context.Context, *Config) error {
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return nil
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}
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// Location returns /dev/null.
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func (DiscardStore) Location() string {
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return "/dev/null"
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}
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// OptConfigLockTimeout is the time allowed to acquire the config lock.
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var OptConfigLockTimeout = options.NewDuration(
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"config.lock.timeout",
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nil,
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time.Second*5,
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"Wait timeout to acquire config lock",
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`Wait timeout to acquire the config lock (which prevents multiple sq instances
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stepping on each other's config changes). During this period, retry will occur
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if the lock is already held by another process. If zero, no retry occurs.`,
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)
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