Documentation
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Overview ¶
Package wait is a library for waiting on events. It currently provides functions for waiting for one or more TCP servers to be ready.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func AllTCP ¶
func AllTCP(specs []*TCPSpec, waitTimeout time.Duration) <-chan *TCPMessage
AllTCP waits until connections can be made to all given TCP input specifications for at most `waitTimeout` long. It returns a channel through which all wait operation-related messages will be sent. The returned channel is closed after all wait operations have finished.
func OneTCP ¶
func OneTCP(spec *TCPSpec, waitTimeout time.Duration) <-chan *TCPMessage
OneTCP waits until a TCP connection can be made to an address, attempting a connection every defined interval. Both of these are contained in the given specifications. It also accepts a context function, which it uses to listen to cancellation events from the parent context. The returned channel is closed after the wait operation has finished or if the parent context is cancelled.
Types ¶
type Message ¶
type Message interface {
// Status returns the status of the message.
Status() Status
// Target returns the entity being waited.
Target() string
// Err returns an error, if the message contains any.
Err() error
// ElapsedTime returns the duration of the wait operation at the time of message creation.
ElapsedTime() time.Duration
}
Message is the interface for messages sent by the wait operations.
type TCPMessage ¶
type TCPMessage struct {
// contains filtered or unexported fields
}
TCPMessage is a container for wait operations on TCP servers.
func (*TCPMessage) Addr ¶
func (msg *TCPMessage) Addr() string
Addr returns the address being waited. If the specifications is nil, this returns `<none>`.
func (*TCPMessage) ElapsedTime ¶
func (msg *TCPMessage) ElapsedTime() time.Duration
ElapsedTime is the duration between waiting operation start and status emission.
func (*TCPMessage) Err ¶
func (msg *TCPMessage) Err() error
Err returns the error contained in the message, if any.
func (*TCPMessage) Status ¶
func (msg *TCPMessage) Status() Status
Status returns the status of the message.
func (*TCPMessage) Target ¶
func (msg *TCPMessage) Target() string
Target returns the target of the wait operation, which is `tcp://` prepended to Addr. If the specifications is nil, this returns `<none>`.
type TCPSpec ¶
type TCPSpec struct {
// Host is the hostname or IP address being waited.
Host string
// Port is the port number for the connection.
Port string
// PollFreq is how often a connection is attempted.
PollFreq time.Duration
}
TCPSpec represents the input specification of a single TCP wait operation.
func ParseTCPSpec ¶
ParseTCPSpec parses the given address into a TCPSpec and then returns a pointer to it. The address can be given in several forms: `<host>:<port>`, `<protocol>://<host>`, or `<protocol>://<host>:<port>`. For the second form, if the protocol is known, the port will be inferred from it (e.g. port 80 for HTTP and 443 for HTTPS). For the last form, the `<protocol>` is ignored. This function also takes a `defaultPollFreq` argument, which it will use as the poll frequency of the TCPSpec if the raw address does not specify a poll frequency value. The poll frequency value in the raw address is the string value of time.Duration, appended to the address after a `#` sign.
Example ¶
spec, _ := ParseTCPSpec("golang.org:80", 1*time.Second)
fmt.Println("host:", spec.Host)
fmt.Println("port:", spec.Port)
fmt.Println("poll freq:", spec.PollFreq)
Output: host: golang.org port: 80 poll freq: 1s
Example (Freq) ¶
spec, _ := ParseTCPSpec("amqps://127.0.0.1#500ms", 1*time.Second)
fmt.Println("host:", spec.Host)
fmt.Println("port:", spec.Port)
fmt.Println("poll freq:", spec.PollFreq)
Output: host: 127.0.0.1 port: 5671 poll freq: 500ms
Example (Proto) ¶
spec, _ := ParseTCPSpec("https://golang.org", 1*time.Second)
fmt.Println("host:", spec.Host)
fmt.Println("port:", spec.Port)
fmt.Println("poll freq:", spec.PollFreq)
Output: host: golang.org port: 443 poll freq: 1s
func ParseTCPSpecs ¶
ParseTCPSpecs parses multiple addresses into separate TCPSpecs, returned as a slice of pointers. It has the same semantics as `ParseTCPSpec`, only it works with multiple addresses instead of one.
Source Files