How to Manage Variables

Learn how to use template variables with SetVar() and GetVar().

Set a Variable

conv.SetVar("user_name", "Alice")

Get a Variable

name := conv.GetVar("user_name")
fmt.Println(name)  // "Alice"

Set Multiple Variables

conv.SetVars(map[string]any{
    "user_name": "Alice",
    "role":      "admin",
    "language":  "en",
})

Variable Types

Variables support any JSON-serializable type:

// Strings
conv.SetVar("name", "Alice")

// Numbers
conv.SetVar("count", 42)
conv.SetVar("score", 98.5)

// Booleans
conv.SetVar("is_premium", true)

// Slices
conv.SetVar("tags", []string{"vip", "active"})

// Maps
conv.SetVar("metadata", map[string]any{
    "region": "us-west",
    "tier":   "gold",
})

Use in Templates

Variables are substituted in system prompts:

Pack file:

{
  "prompts": {
    "support": {
      "system_template": "You are helping {{user_name}}. They are a {{role}} user."
    }
  }
}

Code:

conv.SetVar("user_name", "Alice")
conv.SetVar("role", "premium")

// System prompt becomes:
// "You are helping Alice. They are a premium user."

Environment Variables

Load from environment:

import "os"

// Single variable
conv.SetVar("api_key", os.Getenv("MY_API_KEY"))

// From environment with prefix
conv.SetVarsFromEnv("MYAPP_")
// MYAPP_USER_NAME -> "user_name"
// MYAPP_API_KEY -> "api_key"

Check if Set

value := conv.GetVar("optional_var")
if value == nil {
    // Variable not set
    conv.SetVar("optional_var", "default")
}

Thread Safety

Variables are thread-safe:

var wg sync.WaitGroup

for i := 0; i < 10; i++ {
    wg.Add(1)
    go func(n int) {
        defer wg.Done()
        conv.SetVar(fmt.Sprintf("var_%d", n), n)
    }(i)
}

wg.Wait()

Fork Isolation

Forked conversations have isolated variables:

conv1, _ := sdk.Open("./pack.json", "chat")
conv1.SetVar("user", "Alice")

// Fork creates a copy
conv2 := conv1.Fork()
conv2.SetVar("user", "Bob")

// Variables are isolated
fmt.Println(conv1.GetVar("user"))  // "Alice"
fmt.Println(conv2.GetVar("user"))  // "Bob"

Complete Example

package main

import (
    "context"
    "fmt"
    "log"

    "github.com/AltairaLabs/PromptKit/sdk"
)

func main() {
    conv, _ := sdk.Open("./support.pack.json", "support")
    defer conv.Close()

    // Set customer context
    conv.SetVars(map[string]any{
        "customer_name": "Alice",
        "customer_tier": "gold",
        "language":      "English",
    })

    // Variables are used in system prompt
    ctx := context.Background()
    resp, _ := conv.Send(ctx, "I need help with my order")
    
    fmt.Println(resp.Text())
}