46 lines
1.5 KiB
Go
46 lines
1.5 KiB
Go
package resource
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import (
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"fmt"
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"strings"
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"sync"
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"time"
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)
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const UniqueIdPrefix = `terraform-`
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// idCounter is a monotonic counter for generating ordered unique ids.
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var idMutex sync.Mutex
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var idCounter uint32
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// Helper for a resource to generate a unique identifier w/ default prefix
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func UniqueId() string {
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return PrefixedUniqueId(UniqueIdPrefix)
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}
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// UniqueIDSuffixLength is the string length of the suffix generated by
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// PrefixedUniqueId. This can be used by length validation functions to
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// ensure prefixes are the correct length for the target field.
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const UniqueIDSuffixLength = 26
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// Helper for a resource to generate a unique identifier w/ given prefix
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//
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// After the prefix, the ID consists of an incrementing 26 digit value (to match
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// previous timestamp output). After the prefix, the ID consists of a timestamp
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// and an incrementing 8 hex digit value The timestamp means that multiple IDs
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// created with the same prefix will sort in the order of their creation, even
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// across multiple terraform executions, as long as the clock is not turned back
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// between calls, and as long as any given terraform execution generates fewer
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// than 4 billion IDs.
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func PrefixedUniqueId(prefix string) string {
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// Be precise to 4 digits of fractional seconds, but remove the dot before the
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// fractional seconds.
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timestamp := strings.Replace(
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time.Now().UTC().Format("20060102150405.0000"), ".", "", 1)
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idMutex.Lock()
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defer idMutex.Unlock()
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idCounter++
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return fmt.Sprintf("%s%s%08x", prefix, timestamp, idCounter)
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}
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