Documentation
¶
Overview ¶
Package google is the weft adapter for the Gemini API via the official google.golang.org/genai SDK. weft never owns the HTTP: every request goes through the SDK's client, and the SDK's stream iterator is the contract.
Mapping highlights (ADR 0013 has the full tables):
- Tool definitions become function declarations from Schema. Thought signatures round-trip as reasoning: surfaced from whichever part carries them, sent back on the first function call of a tool turn (where the API validates them) or on a thought part otherwise; unsigned reasoning is dropped.
- FilePart becomes inline data (base64) or a file URI.
- Function calls arrive whole; the adapter prefers the call id the API populates and synthesises call_<i> per step when absent, matching responses by position (the API matches by name and order).
- SequentialTools has no Gemini switch: function-calling config stays AUTO and the adapter's conformance run declares the sequential cap false — a documented gap, not a silent one.
- ModelRequest.Thinking maps onto thinkingConfig: Off zeroes the budget (Gemini's off switch), a Budget pins it, a bare level maps to thinkingLevel — and asks for thought summaries back so reasoning streams (ADR 0013 amendment 9).
Retry stance: transport retries (429, 5xx, connection errors) belong to the SDK via MaxRetries (off unless asked); the weft loop never retries a model call, and logic retries are model-seam middleware.
Vertex AI and Bedrock-style setups compose through Client(c) with their own genai.Client. Grounding, search, and code-execution tools are not wrapped here.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Model ¶
Model returns a weft.Model backed by the Gemini API. The SDK client is created lazily on the first run (its constructor wants a context for credential discovery), so constructing a Model performs no I/O. A Model is immutable and safe for concurrent runs.
Example ¶
Constructing a model performs no I/O; credentials ($GEMINI_API_KEY / $GOOGLE_API_KEY, then application default) are read on the first run. Swap providers by swapping this one line.
package main
import (
"context"
"github.com/weftgo/weft"
"github.com/weftgo/weft/google"
)
func main() {
m := google.Model("gemini-2.5-flash")
echo := weft.Tool("echo", "Echo a message.", func(ctx context.Context, in struct {
Message string `json:"message" jsonschema:"the text to repeat"`
}) (string, error) {
return in.Message, nil
})
agt := weft.New(m, echo)
_ = agt // a run is agt.Generate(ctx, weft.Prompt("Echo: hello"))
}
Output:
Types ¶
type Option ¶
type Option interface {
// contains filtered or unexported methods
}
Option configures the adapter at construction, the same functional style as the core. The zero configuration discovers credentials the SDK's way ($GOOGLE_API_KEY / $GEMINI_API_KEY, then application default) and does not set a base URL.
func APIKey ¶
APIKey sets the API key. Default: the SDK's own discovery ($GOOGLE_API_KEY / $GEMINI_API_KEY, then application default credentials).
func BaseURL ¶
BaseURL points the adapter at a custom endpoint (a gateway, a proxy). When the option is not given the SDK applies its own $GOOGLE_GEMINI_BASE_URL.
func Client ¶
Client uses an already-configured SDK client (Vertex AI projects and regions, test doubles); it overrides BaseURL, APIKey, and MaxRetries. The WEFT_MODEL_REQUESTS kill switch guards egress from clients the adapter builds from credentials; an injected client's destinations are the caller's responsibility — which is why it stays reachable under deny (ADR 0013's kill-switch clause).
func IdleTimeout ¶
IdleTimeout is the maximum gap between two stream chunks before the call fails wrapping weft.ErrStreamIdle (default 60s; zero disables it). The ctx deadline stays the hard limit on the whole call — a slow but actively streaming response is never killed.
func MaxRetries ¶
MaxRetries forwards to the SDK's transport retry configuration (429/5xx/connection errors only; the SDK retries nothing unless asked). The weft loop never retries a model call; logic retries are model-seam middleware (TODO §4.1).
func MaxTokens ¶
MaxTokens caps a step's output tokens (maxOutputTokens). Zero keeps the provider default. The API's limit is an int32: a value above math.MaxInt32 fails the call wrapping weft.ErrUnsupported rather than wrapping around on the wire. Options carry no error channel, so the check lands at convert time — the first place that can refuse — not at construction.
func Temperature ¶
Temperature sets the sampling temperature; it is not sent unless the option is given.
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