Fix the docs and add an appropriate FromEnv func for message queues

Author: scott-cotton

go-routesapi/docs/message-queues.md

@@ -55,7 +55,7 @@ rules for a baseline workload from the environment:
 
 ```go
 import "github.com/signadot/routesapi/go-routesapi/watched"
-routing, err := watched.BaselineFromEnv()
+routing, err := watched.BaselineWatchedFromEnv()
 ```
 
 ## Using `routesapi` Go SDK
@@ -75,7 +75,7 @@ In a sandboxed workload:
 import "github.com/signadot/routesapi/go-routesapi/watched"
 
 func ShouldProcess(routing watched.BaselineWatched, routingKey string) bool {
-    return routing.RoutesTo(routingKey, os.Getenv("SIGNADOT_SANDBOX_ROUTING_KEY"))
+    return routing.RoutesTo(routingKey, os.Getenv("SIGNADOT_SANDBOX_NAME"))
 }
 ```
 
@@ -84,8 +84,8 @@ unconditionally.  This can be accomplished as follows:
 
 ```go
 func ShouldProcess(routing watched.BaselineWatched, routingKey string) bool {
-    if sbID := os.Getenv("SIGNADOT_SANDBOX_ROUTING_KEY"); sbID != "" {
-       return routing.RoutesTo(routingKey, sbID)
+    if sb := os.Getenv("SIGNADOT_SANDBOX_NAME"); sb != "" {
+       return routing.RoutesTo(routingKey, sb)
     }
     return routing.Get(routingKey) == nil
 }

go-routesapi/watched/baseline_watched.go

@@ -2,14 +2,22 @@ package watched
 
 import (
 	"context"
+	"fmt"
+	"log/slog"
 
 	"github.com/signadot/routesapi/go-routesapi"
 	"google.golang.org/protobuf/proto"
 )
 
 // BaselineWatched wraps [watched.Watched] with a [routesapi.BaselineWorkload].
 type BaselineWatched interface {
+	// Get returns a workload routing rule associated with
+	// the routing key rk for the associated baseline workload.
 	Get(rk string) *routesapi.WorkloadRoutingRule
+
+	// RoutesTo returns true if traffic destined to the associated
+	// baseline workload with routing key rk should be directed to
+	// the sandbox named sbName.
 	RoutesTo(rk string, sbName string) bool
 }
 
@@ -18,6 +26,10 @@ type baselineWatched struct {
 	baseline *routesapi.BaselineWorkload
 }
 
+// NewBaselineWatched creates a BaselineWatched instance using
+// ctx for the underlying grpc watch rpc, using the routeserver
+// specified in [cfg.Addr], and associated with the baseline
+// specified in b.
 func NewBaselineWatched(ctx context.Context, cfg *Config, b *routesapi.BaselineWorkload) (BaselineWatched, error) {
 	bb := proto.Clone(b).(*routesapi.BaselineWorkload)
 	w, err := NewWatched(ctx, cfg, &routesapi.WorkloadRoutingRulesRequest{
@@ -32,6 +44,30 @@ func NewBaselineWatched(ctx context.Context, cfg *Config, b *routesapi.BaselineW
 	}, nil
 }
 
+// BaselineWatchedFromEnv attempts to construct a BaselineWatched instance
+// using configuration from the environment, by using
+// [BaselineFromEnv] and [GetRouteServerAddr] and calling
+// [NewBaselineWatched].  The context associated with the watch
+// is the result of calling [context.Background] and the logger
+// is the result of calling [slog.Default].  For more control,
+// please use [NewBaselineWatched] directly.
+func BaselineWatchedFromEnv() (BaselineWatched, error) {
+	baseline, err := BaselineFromEnv()
+	if err != nil {
+		return nil, fmt.Errorf("could not get baseline from env: %w", err)
+	}
+	cfg := &Config{
+		Addr: GetRouteServerAddr(),
+		Log:  slog.Default(),
+	}
+	apiBaseline := &routesapi.BaselineWorkload{
+		Kind:      baseline.Kind,
+		Namespace: baseline.Namespace,
+		Name:      baseline.Name,
+	}
+	return NewBaselineWatched(context.Background(), cfg, apiBaseline)
+}
+
 func (bw *baselineWatched) Get(rk string) *routesapi.WorkloadRoutingRule {
 	return bw.watched.Get(bw.baseline, rk)
 }