Refactor environment handling logic to separate a server from the environment handler itself

This change makes the environment handling logic execute independent of the server itself and should make it much easier for people to contribute changes and additional environment handlers down the road without polluting the server object even more.

There is still a lot of work to do on this front to make things easier to work with, and there are some questionable design decisions at play I'm sure.

Welcome to additional modifications and cleanup to make this code easier to reason about and work with.

environment/config.go

@@ -0,0 +1,84 @@
+package environment
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+)
+
+type configurationSettings struct {
+	Mounts      []Mount
+	Allocations Allocations
+	Limits      Limits
+	Variables   Variables
+}
+
+// Defines the actual configuration struct for the environment with all of the settings
+// defined within it.
+type Configuration struct {
+	mu sync.RWMutex
+
+	settings configurationSettings
+}
+
+func NewConfiguration(m []Mount, a Allocations, l Limits, v Variables) *Configuration {
+	return &Configuration{
+		settings: configurationSettings{
+			Mounts:      m,
+			Allocations: a,
+			Limits:      l,
+			Variables:   v,
+		},
+	}
+}
+
+func (c *Configuration) Limits() Limits {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.settings.Limits
+}
+
+func (c *Configuration) Allocations() Allocations {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.settings.Allocations
+}
+
+func (c *Configuration) Mounts() []Mount {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.settings.Mounts
+}
+
+// Returns all of the environment variables that should be assigned to a running
+// server instance.
+func (c *Configuration) EnvironmentVariables() []string {
+	c.mu.RLock()
+	c.mu.RUnlock()
+
+	zone, _ := time.Now().In(time.Local).Zone()
+
+	var out = []string{
+		fmt.Sprintf("TZ=%s", zone),
+		fmt.Sprintf("SERVER_MEMORY=%d", c.settings.Limits.MemoryLimit),
+		fmt.Sprintf("SERVER_IP=%s", c.settings.Allocations.DefaultMapping.Ip),
+		fmt.Sprintf("SERVER_PORT=%d", c.settings.Allocations.DefaultMapping.Port),
+	}
+
+eloop:
+	for k := range c.settings.Variables {
+		for _, e := range out {
+			if strings.HasPrefix(e, strings.ToUpper(k)) {
+				continue eloop
+			}
+		}
+
+		out = append(out, fmt.Sprintf("%s=%s", strings.ToUpper(k), c.settings.Variables.Get(k)))
+	}
+
+	return out
+}