refactor: internal package

internal/sandbox/config.go

@@ -0,0 +1,43 @@
+// Creates sandboxes according to the configuration.
+package sandbox
+
+import (
+	"fmt"
+
+	"github.com/nalgeon/codapi/internal/config"
+	"github.com/nalgeon/codapi/internal/engine"
+)
+
+// A semaphore represents available concurrent workers
+// that are responsible for executing code in sandboxes.
+// The workers themselves are external to this package
+// (the calling goroutines are workers).
+var semaphore *Semaphore
+
+var engineConstr = map[string]func(*config.Config, string, string) engine.Engine{
+	"docker": engine.NewDocker,
+	"http":   engine.NewHTTP,
+}
+
+// engines is the registry of command executors.
+// Each engine executes a specific command in a specifix sandbox.
+// sandbox : command : engine
+// TODO: Maybe it's better to create a single instance of each engine
+// and pass the sandbox and command as arguments to the Exec.
+var engines = map[string]map[string]engine.Engine{}
+
+// ApplyConfig fills engine registry according to the configuration.
+func ApplyConfig(cfg *config.Config) error {
+	semaphore = NewSemaphore(cfg.PoolSize)
+	for sandName, sandCmds := range cfg.Commands {
+		engines[sandName] = make(map[string]engine.Engine)
+		for cmdName, cmd := range sandCmds {
+			constructor, ok := engineConstr[cmd.Engine]
+			if !ok {
+				return fmt.Errorf("unknown engine: %s", cmd.Engine)
+			}
+			engines[sandName][cmdName] = constructor(cfg, sandName, cmdName)
+		}
+	}
+	return nil
+}