Initialization

Constructor


client := canarygate.New("cg_api_key", canarygate.Options{})

Parameters

Parameter	Type	Required	Description
`apiKey`	`string`	Yes	Environment API Key. Created under Settings → API Keys.
`options`	`canarygate.Options`	No	Configuration options. See below.

`Options`

Field	Type	Default	Description
`BaseURL`	`string`	`http://localhost:3001`	API base URL (useful for self-hosted environments or proxies).
`Environment`	`string`	default environment	Environment slug, sent via the `X-Environment` header.
`Stream`	`bool`	`false`	Opt in to real-time SSE streaming.
`ReconnectDelay`	`time.Duration`	`5 * time.Second`	Initial delay before reconnecting a dropped stream.
`MaxReconnectDelay`	`time.Duration`	`30 * time.Second`	Maximum backoff delay for stream reconnection.
`HeartbeatTimeoutMs`	`time.Duration`	`65 * time.Second`	Time without a server heartbeat before the stream is considered dead and reconnects.

`Init()`


if err := client.Init(); err != nil {
    log.Fatal(err)
}

Executes two actions in sequence:

Makes an HTTP fetch to load all flags for the environment (snapshot)
Opens the SSE connection — only when Stream is enabled. Otherwise flags come from the snapshot request only.

Unlike the JavaScript SDK, Init() returns an error if the initial snapshot request fails. After a successful Init(), GetFlag() reads from the local cache; if the connection degrades later, IsStale() reports it and GetFlag() continues to return the last known values.

Examples

Server (HTTP handler with streaming)


package main
 
import (
    "log"
    "net/http"
 
    "github.com/canarygate/sdk-go"
)
 
func main() {
    client := canarygate.New("cg_api_key", canarygate.Options{
        Environment: "production",
        Stream:      true,
    })
 
    if err := client.Init(); err != nil {
        log.Fatal(err)
    }
    defer client.Disconnect()
 
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        flag := client.GetFlag("new-checkout", &canarygate.FlagEvaluationContext{
            UserID: "user-42",
        })
        if flag != nil && flag.Enabled {
            // Serve the new checkout
        }
    })
 
    log.Fatal(http.ListenAndServe(":8080", nil))
}

One-shot script (no stream)


client := canarygate.New("cg_api_key", canarygate.Options{})
if err := client.Init(); err != nil {
    log.Fatal(err)
}
defer client.Disconnect()
 
flag := client.GetFlag("run-migration", nil)
if flag != nil && flag.Enabled {
    runMigration()
}