1. Home
  2. Reference documentation
  3. Compute
  4. Language SDKs
  5. Go
  6. compute-sdk-go
  7. core

WriteOptions

Structin corecompute-sdk-go v1.11.0View source
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
type WriteOptions struct {
	TTL time.Duration


	RequestHeaders fsthttp.Header


	Vary []string


	InitialAge time.Duration


	StaleWhileRevalidate time.Duration


	SurrogateKeys []string


	Length uint64


	UserMetadata []byte


	SensitiveData bool
}

WriteOptions control the behavior of cache inserts and updates. TTL is required, but all other fields are optional.

Fields

TTL

time.Duration

TTL is the maximum time the cached object will be considered fresh. Required.

RequestHeaders

fsthttp.Header

RequestHeaders are a set of HTTP headers that influence cache lookups when Vary rules are set.

This field is only valid for Insert outside of a transaction. If provided to Insert or Update inside a transaction, ErrInvalidArgument will be returned.

Vary

[]string

Vary is a list of HTTP header names (provided in RequestHeaders) that must match when looking up this key.

InitialAge

time.Duration

InitialAge is the initial age of the cached object.

StaleWhileRevalidate

time.Duration

StaleWhileRevalidate is the period of time in which the cached object can be served stale while revalidation is taking place.

This provides a signal that the cache should be updated (or its contents otherwise revalidated for freshness) asynchronously, while the stale cached object continues to be used, rather than blocking on updating the cached object. The methods Usable and Stale can be used to determine the current state of a found item.

SurrogateKeys

[]string

SurrogateKeys is a list of surrogate keys which can be used to purge this object.

Surrogate key purges are the only means to purge specific items from the cache. At least one surrogate key must be set in order to remove an item without performaing a purge-all, waiting for the item's TTL to elapse, or overwriting the item with Insert.

Surrogate keys must contain only printable ASCII characters (those between 0x21 and 0x7E, inclusive). Any invalid keys will be ignored.

See the Fastly surrogate keys guide for details: https://docs.fastly.com/en/guides/purging-api-cache-with-surrogate-keys

Length

uint64

Length sets the size of the cached object, in bytes, when known prior to actually providing the bytes.

It is preferable to provide a length, if possible. Clients that begin streaming the object's contents before it is completely provided will see the promised length which allows them to, for example, use Content-Length instead of chunked Transfer-Encoding if the item is used as the body of an HTTP request or response.

UserMetadata

[]byte

UserMetadata is abitrary user-provided metadata that will be associated with the cached object.

SensitiveData

bool

SensitiveData indiciates whether to enable PCI/HIPAA-compliant non-volatile caching.

See the Fastly PCI-Compliant Caching and Delivery documentation for details: https://docs.fastly.com/products/pci-compliant-caching-and-delivery

Fastly
© Fastly 2026