Documentation
¶
Index ¶
- Variables
- func BasicAuth(user, pass string) string
- func BearerAuth(token string) string
- func Contains[T comparable](haystack []T, needle T) bool
- func ContainsAll[T comparable](haystack []T, needles []T) bool
- func ContainsIP(haystack []netip.Prefix, needle netip.Addr) bool
- func DetectContentType(b []byte, filename string) (mimeType string, ext string)
- func FileExists(filename string) bool
- func FormatSize(b int64) string
- func FormatTime(t time.Time) string
- func Gzip(next http.Handler) http.Handler
- func Int(v int) *int
- func LastString(s []string, def string) string
- func Max[T int | int64 | rate.Limit](a, b T) T
- func MaybeMarshalJSON(v any) string
- func MinMax[T int | int64](value, min, max T) T
- func NextOccurrenceUTC(timeOfDay, base time.Time) time.Time
- func ParseDuration(s string) (time.Duration, error)
- func ParseFutureTime(s string, now time.Time) (time.Time, error)
- func ParsePriority(priority string) (int, error)
- func ParseSize(s string) (int64, error)
- func PriorityString(priority int) (string, error)
- func QuoteCommand(command []string) string
- func RandomLowerStringPrefix(prefix string, length int) string
- func RandomString(length int) string
- func RandomStringPrefix(prefix string, length int) string
- func ReadPassword(in io.Reader) ([]byte, error)
- func Retry[T any](f func() (*T, error), after ...time.Duration) (t *T, err error)
- func ShortTopicURL(s string) string
- func SplitKV(s string, sep string) (key string, value string)
- func SplitNoEmpty(s string, sep string) []string
- func String(v string) *string
- func Time(v time.Time) *time.Time
- func UnmarshalJSON[T any](body io.ReadCloser) (*T, error)
- func UnmarshalJSONWithLimit[T any](r io.ReadCloser, limit int, allowEmpty bool) (*T, error)
- func ValidRandomString(s string, length int) bool
- type BatchingQueue
- type CachingEmbedFS
- type ContentTypeWriter
- type FixedLimiter
- type LimitWriter
- type Limiter
- type LookupCache
- type LookupFunc
- type PeekedReadCloser
- type RateLimiter
Constants ¶
This section is empty.
Variables ¶
var ( ErrUnmarshalJSON = errors.New("unmarshalling JSON failed") ErrTooLargeJSON = errors.New("too large JSON") )
Errors for UnmarshalJSON and UnmarshalJSONWithLimit functions
var ErrLimitReached = errors.New("limit reached")
ErrLimitReached is the error returned by the Limiter and LimitWriter when the predefined limit has been reached
Functions ¶
func BearerAuth ¶
BearerAuth encodes the Authorization header value for a bearer/token auth
func Contains ¶
func Contains[T comparable](haystack []T, needle T) bool
Contains returns true if needle is contained in haystack
func ContainsAll ¶
func ContainsAll[T comparable](haystack []T, needles []T) bool
ContainsAll returns true if all needles are contained in haystack
func ContainsIP ¶
ContainsIP returns true if any one of the of prefixes contains the ip.
func DetectContentType ¶
DetectContentType probes the byte array b and returns mime type and file extension. The filename is only used to override certain special cases.
func FileExists ¶
FileExists checks if a file exists, and returns true if it does
func FormatSize ¶
FormatSize formats bytes into a human-readable notation, e.g. 2.1 MB
func FormatTime ¶
FormatTime formats a time.Time in a RFC339-like format that includes milliseconds
func Gzip ¶
Gzip is a HTTP middleware to transparently compress responses using gzip. Original code from https://gist.github.com/CJEnright/bc2d8b8dc0c1389a9feeddb110f822d7 (MIT)
func LastString ¶
LastString returns the last string in a slice, or def if s is empty
func MaybeMarshalJSON ¶
MaybeMarshalJSON returns a JSON string of the given object, or "<cannot serialize>" if serialization failed. This is useful for logging purposes where a failure doesn't matter that much.
func MinMax ¶
MinMax returns value if it is between min and max, or either min or max if it is out of range
func NextOccurrenceUTC ¶
NextOccurrenceUTC takes a time of day (e.g. 9:00am), and returns the next occurrence of that time from the current time (in UTC).
func ParseDuration ¶
ParseDuration is like time.ParseDuration, except that it also understands days (d), which translates to 24 hours, e.g. "2d" or "20h".
func ParseFutureTime ¶
ParseFutureTime parses a date/time string to a time.Time. It supports unix timestamps, durations and natural language dates
func ParsePriority ¶
ParsePriority parses a priority string into its equivalent integer value
func ParseSize ¶
ParseSize parses a size string like 2K or 2M into bytes. If no unit is found, e.g. 123, bytes is assumed.
func PriorityString ¶
PriorityString converts a priority number to a string
func QuoteCommand ¶
QuoteCommand combines a command array to a string, quoting arguments that need quoting. This function is naive, and sometimes wrong. It is only meant for lo pretty-printing a command.
Warning: Never use this function with the intent to run the resulting command.
Example:
[]string{"ls", "-al", "Document Folder"} -> ls -al "Document Folder"
func RandomLowerStringPrefix ¶
RandomLowerStringPrefix returns a random lowercase-only string with a given length, with a prefix
func RandomString ¶
RandomString returns a random string with a given length
func RandomStringPrefix ¶
RandomStringPrefix returns a random string with a given length, with a prefix
func ReadPassword ¶
ReadPassword will read a password from STDIN. If the terminal supports it, it will not print the input characters to the screen. If not, it'll just read using normal readline semantics (useful for testing).
func Retry ¶
Retry executes function f until if succeeds, and then returns t. If f fails, it sleeps and tries again. The sleep durations are passed as the after params.
func ShortTopicURL ¶
ShortTopicURL shortens the topic URL to be human-friendly, removing the http:// or https://
func SplitKV ¶
SplitKV splits a string into a key/value pair using a separator, and trimming space. If the separator is not found, key is empty.
func SplitNoEmpty ¶
SplitNoEmpty splits a string using strings.Split, but filters out empty strings
func UnmarshalJSON ¶
func UnmarshalJSON[T any](body io.ReadCloser) (*T, error)
UnmarshalJSON reads the given io.ReadCloser into a struct
func UnmarshalJSONWithLimit ¶
UnmarshalJSONWithLimit reads the given io.ReadCloser into a struct, but only until limit is reached
func ValidRandomString ¶
ValidRandomString returns true if the given string matches the format created by RandomString
Types ¶
type BatchingQueue ¶
type BatchingQueue[T any] struct { // contains filtered or unexported fields }
BatchingQueue is a queue that creates batches of the enqueued elements based on a max batch size and a batch timeout.
Example:
q := NewBatchingQueue[int](2, 500 * time.Millisecond)
go func() {
for batch := range q.Dequeue() {
fmt.Println(batch)
}
}()
q.Enqueue(1)
q.Enqueue(2)
q.Enqueue(3)
time.Sleep(time.Second)
This example will emit batch [1, 2] immediately (because the batch size is 2), and a batch [3] after 500ms.
func NewBatchingQueue ¶
func NewBatchingQueue[T any](batchSize int, timeout time.Duration) *BatchingQueue[T]
NewBatchingQueue creates a new BatchingQueue
func (*BatchingQueue[T]) Dequeue ¶
func (q *BatchingQueue[T]) Dequeue() <-chan []T
Dequeue returns a channel emitting batches of elements
func (*BatchingQueue[T]) Enqueue ¶
func (q *BatchingQueue[T]) Enqueue(element T)
Enqueue enqueues an element to the queue. If the configured batch size is reached, the batch will be emitted immediately.
type CachingEmbedFS ¶
CachingEmbedFS is a wrapper around embed.FS that allows setting a ModTime, so that the default static file server can send 304s back. It can be used like this:
var (
//go:embed docs
docsStaticFs embed.FS
docsStaticCached = &util.CachingEmbedFS{ModTime: time.Now(), FS: docsStaticFs}
)
http.FileServer(http.FS(docsStaticCached)).ServeHTTP(w, r)
type ContentTypeWriter ¶
type ContentTypeWriter struct {
// contains filtered or unexported fields
}
ContentTypeWriter is an implementation of http.ResponseWriter that will detect the content type and set the Content-Type and (optionally) Content-Disposition headers accordingly.
It will always set a Content-Type based on http.DetectContentType, but will never send the "text/html" content type.
func NewContentTypeWriter ¶
func NewContentTypeWriter(w http.ResponseWriter, filename string) *ContentTypeWriter
NewContentTypeWriter creates a new ContentTypeWriter
type FixedLimiter ¶
type FixedLimiter struct {
// contains filtered or unexported fields
}
FixedLimiter is a helper that allows adding values up to a well-defined limit. Once the limit is reached ErrLimitReached will be returned. FixedLimiter may be used by multiple goroutines.
func NewFixedLimiter ¶
func NewFixedLimiter(limit int64) *FixedLimiter
NewFixedLimiter creates a new Limiter
func NewFixedLimiterWithValue ¶
func NewFixedLimiterWithValue(limit, value int64) *FixedLimiter
NewFixedLimiterWithValue creates a new Limiter and sets the initial value
func (*FixedLimiter) Allow ¶
func (l *FixedLimiter) Allow() bool
Allow adds one to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded, false is returned.
func (*FixedLimiter) AllowN ¶
func (l *FixedLimiter) AllowN(n int64) bool
AllowN adds n to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded after adding n, false is returned.
func (*FixedLimiter) Reset ¶
func (l *FixedLimiter) Reset()
Reset sets the limiter's value back to zero
func (*FixedLimiter) Value ¶
func (l *FixedLimiter) Value() int64
Value returns the current limiter value
type LimitWriter ¶
type LimitWriter struct {
// contains filtered or unexported fields
}
LimitWriter implements an io.Writer that will pass through all Write calls to the underlying writer w until any of the limiter's limit is reached, at which point a Write will return ErrLimitReached. Each limiter's value is increased with every write.
func NewLimitWriter ¶
func NewLimitWriter(w io.Writer, limiters ...Limiter) *LimitWriter
NewLimitWriter creates a new LimitWriter
type Limiter ¶
type Limiter interface {
// Allow adds one to the limiters value, or returns false if the limit has been reached
Allow() bool
// AllowN adds n to the limiters value, or returns false if the limit has been reached
AllowN(n int64) bool
// Value returns the current internal limiter value
Value() int64
// Reset resets the state of the limiter
Reset()
}
Limiter is an interface that implements a rate limiting mechanism, e.g. based on time or a fixed value
type LookupCache ¶
type LookupCache[T any] struct { // contains filtered or unexported fields }
LookupCache is a single-value cache with a time-to-live (TTL). The cache has a lookup function to retrieve the value and stores it until TTL is reached.
Example:
lookup := func() (string, error) {
r, _ := http.Get("...")
s, _ := io.ReadAll(r.Body)
return string(s), nil
}
c := NewLookupCache[string](lookup, time.Hour)
fmt.Println(c.Get()) // Fetches the string via HTTP
fmt.Println(c.Get()) // Uses cached value
func NewLookupCache ¶
func NewLookupCache[T any](lookup LookupFunc[T], ttl time.Duration) *LookupCache[T]
NewLookupCache creates a new LookupCache with a given time-to-live (TTL)
func (*LookupCache[T]) Value ¶
func (c *LookupCache[T]) Value() (T, error)
Value returns the cached value, or retrieves it via the lookup function
type LookupFunc ¶
LookupFunc is a function that is called by the LookupCache if the underlying value is out-of-date. It returns the new value, or an error.
type PeekedReadCloser ¶
type PeekedReadCloser struct {
PeekedBytes []byte
LimitReached bool
// contains filtered or unexported fields
}
PeekedReadCloser is a ReadCloser that allows peeking into a stream and buffering it in memory. It can be instantiated using the Peek function. After a stream has been peeked, it can still be fully read by reading the PeekedReadCloser. It first drained from the memory buffer, and then from the remaining underlying reader.
func Peek ¶
func Peek(underlying io.ReadCloser, limit int) (*PeekedReadCloser, error)
Peek reads the underlying ReadCloser into memory up until the limit and returns a PeekedReadCloser. It does not return an error if limit is reached. Instead, LimitReached will be set to true.
func (*PeekedReadCloser) Close ¶
func (r *PeekedReadCloser) Close() error
Close closes the underlying stream
type RateLimiter ¶
type RateLimiter struct {
// contains filtered or unexported fields
}
RateLimiter is a Limiter that wraps a rate.Limiter, allowing a floating time-based limit.
func NewBytesLimiter ¶
func NewBytesLimiter(bytes int, interval time.Duration) *RateLimiter
NewBytesLimiter creates a RateLimiter that is meant to be used for a bytes-per-interval limit, e.g. 250 MB per day. And example of the underlying idea can be found here: https://go.dev/play/p/0ljgzIZQ6dJ
func NewRateLimiter ¶
func NewRateLimiter(r rate.Limit, b int) *RateLimiter
NewRateLimiter creates a new RateLimiter
func NewRateLimiterWithValue ¶
func NewRateLimiterWithValue(r rate.Limit, b int, value int64) *RateLimiter
NewRateLimiterWithValue creates a new RateLimiter with the given starting value.
Note that the starting value only has informational value. It does not impact the underlying value of the rate.Limiter.
func (*RateLimiter) Allow ¶
func (l *RateLimiter) Allow() bool
Allow adds one to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded, false is returned.
func (*RateLimiter) AllowN ¶
func (l *RateLimiter) AllowN(n int64) bool
AllowN adds n to the limiters internal value, but only if the limit has not been reached. If the limit was exceeded after adding n, false is returned.
func (*RateLimiter) Reset ¶
func (l *RateLimiter) Reset()
Reset sets the limiter's value back to zero, and resets the underlying rate.Limiter
func (*RateLimiter) Value ¶
func (l *RateLimiter) Value() int64
Value returns the current limiter value
Source Files