Rename ControllerConf to BaseConfig

Also moved BaseConfig to a new source file, co-located with its
constructors and methods, and added doc comments.

Signed-off-by: Jonathon Anderson <janderson@ciq.co>

internal/pkg/config/root.go

@@ -0,0 +1,209 @@
+// Package config reads, parses, and represents the warewulf.conf
+// config file.
+//
+// warewulf.conf is a yaml-formatted configuration file that includes
+// configuration for the Warewulf daemon and commands, as well as the
+// DHCP, TFTP and NFS services that Warewulf manages.
+package config
+
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/pkg/errors"
+
+	"github.com/creasty/defaults"
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"gopkg.in/yaml.v2"
+)
+
+
+var (
+	cachedConf RootConf
+	ConfigFile string
+)
+
+
+// RootConf is the main Warewulf configuration structure. It stores
+// some information about the Warewulf server locally, and has
+// [WarewulfConf], [DhcpConf], [TftpConf], and [NfsConf] sub-sections.
+type RootConf struct {
+	WWInternal      int           `yaml:"WW_INTERNAL"`
+	Comment         string        `yaml:"comment,omitempty"`
+	Ipaddr          string        `yaml:"ipaddr"`
+	Ipaddr6         string        `yaml:"ipaddr6,omitempty"`
+	Netmask         string        `yaml:"netmask"`
+	Network         string        `yaml:"network,omitempty"`
+	Ipv6net         string        `yaml:"ipv6net,omitempty"`
+	Fqdn            string        `yaml:"fqdn,omitempty"`
+	Warewulf        *WarewulfConf `yaml:"warewulf"`
+	Dhcp            *DhcpConf     `yaml:"dhcp"`
+	Tftp            *TftpConf     `yaml:"tftp"`
+	Nfs             *NfsConf      `yaml:"nfs"`
+	MountsContainer []*MountEntry `yaml:"container mounts" default:"[{\"source\": \"/etc/resolv.conf\", \"dest\": \"/etc/resolv.conf\"}]"`
+	Paths           *BuildConfig  `yaml:"paths"`
+	current         bool
+	readConf        bool
+}
+
+
+// New returns a [RootConf] which may have been cached from a previous
+// call.
+func New() (conf RootConf) {
+	// NOTE: This function can be called before any log level is set
+	//       so using wwlog.Verbose or wwlog.Debug won't work
+	if !cachedConf.current {
+		conf.Warewulf = new(WarewulfConf)
+		conf.Dhcp = new(DhcpConf)
+		conf.Tftp = new(TftpConf)
+		conf.Nfs = new(NfsConf)
+		conf.Paths = new(BuildConfig)
+		_ = defaults.Set(&conf)
+		cachedConf = conf
+		cachedConf.readConf = false
+		cachedConf.current = true
+	} else {
+		// If cached struct isn't empty, use it as the return value
+		conf = cachedConf
+	}
+	return conf
+}
+
+// ReadConf populates the configuration with the values from a
+// configuration file.
+func (conf *RootConf) ReadConf(confFileName string) (err error) {
+	wwlog.Debug("Reading warewulf.conf from: %s", confFileName)
+	fileHandle, err := os.ReadFile(confFileName)
+	if err != nil {
+		return err
+	}
+	return conf.Read(fileHandle)
+}
+
+// Read populates the configuration with the values from a yaml
+// document.
+func (conf *RootConf) Read(data []byte) (err error) {
+	// ipxe binaries are merged not overwritten, store defaults separate
+	defIpxe := make(map[string]string)
+	for k, v := range conf.Tftp.IpxeBinaries {
+		defIpxe[k] = v
+		delete(conf.Tftp.IpxeBinaries, k)
+	}
+	err = yaml.Unmarshal(data, &conf)
+	if err != nil {
+		return
+	}
+	err = conf.SetDynamicDefaults()
+	if err != nil {
+		return
+	}
+	if len(conf.Tftp.IpxeBinaries) == 0 {
+		conf.Tftp.IpxeBinaries = defIpxe
+	}
+	cachedConf = *conf
+	cachedConf.current = true
+	cachedConf.readConf = true
+	return
+}
+
+// SetDynamicDefaults populates the configuration with plausible
+// defaults for the runtime environment.
+func (conf *RootConf) SetDynamicDefaults() (err error) {
+	if conf.Ipaddr == "" || conf.Netmask == "" || conf.Network == "" {
+		var mask net.IPMask
+		var network *net.IPNet
+		var ipaddr net.IP
+
+		if conf.Ipaddr == "" {
+			wwlog.Verbose("Configuration has no valid network, going to dynamic values")
+			conn, _ := net.Dial("udp", "8.8.8.8:80")
+			defer conn.Close()
+			ipaddr = conn.LocalAddr().(*net.UDPAddr).IP
+			mask = ipaddr.DefaultMask()
+			sz, _ := mask.Size()
+			conf.Ipaddr = ipaddr.String() + fmt.Sprintf("/%d", sz)
+		}
+		_, network, err = net.ParseCIDR(conf.Ipaddr)
+		if err == nil {
+			mask = network.Mask
+		} else {
+			return errors.Wrap(err, "Couldn't parse IP address")
+		}
+		if conf.Netmask == "" {
+			conf.Netmask = fmt.Sprintf("%d.%d.%d.%d", mask[0], mask[1], mask[2], mask[3])
+			wwlog.Verbose("Netmask address is not configured in warewulf.conf, using %s", conf.Netmask)
+		}
+		if conf.Network == "" {
+			conf.Network = network.IP.String()
+			wwlog.Verbose("Network is not configured in warewulf.conf, using %s", conf.Network)
+		}
+	}
+	if conf.Dhcp.RangeStart == "" && conf.Dhcp.RangeEnd == "" {
+		start := net.ParseIP(conf.Network).To4()
+		start[3] += 1
+		if start.Equal(net.ParseIP(conf.Ipaddr)) {
+			start[3] += 1
+		}
+		conf.Dhcp.RangeStart = start.String()
+		wwlog.Verbose("dhpd start is not configured in warewulf.conf, using %s", conf.Dhcp.RangeStart)
+		sz, _ := net.IPMask(net.ParseIP(conf.Netmask).To4()).Size()
+		range_end := (1 << (32 - sz)) / 8
+		if range_end > 127 {
+			range_end = 127
+		}
+		end := net.ParseIP(conf.Network).To4()
+		end[3] += byte(range_end)
+		conf.Dhcp.RangeEnd = end.String()
+		wwlog.Verbose("dhpd end is not configured in warewulf.conf, using %s", conf.Dhcp.RangeEnd)
+
+	}
+	// check validity of ipv6 net
+	if conf.Ipaddr6 != "" {
+		_, ipv6net, err := net.ParseCIDR(conf.Ipaddr6)
+		if err != nil {
+			wwlog.Error("Invalid ipv6 address specified, mut be CIDR notation: %s", conf.Ipaddr6)
+			return errors.New("invalid ipv6 network")
+		}
+		if msize, _ := ipv6net.Mask.Size(); msize > 64 {
+			wwlog.Error("ipv6 mask size must be smaller than 64")
+			return errors.New("invalid ipv6 network size")
+		}
+	}
+	cachedConf = *conf
+	cachedConf.current = true
+	return
+}
+
+// Initialized returns true if the configuration in memory was read
+// from disk, or false otherwise.
+func (conf *RootConf) Initialized() bool {
+	return conf.readConf
+}
+
+
+// Persist writes the configuration to a file as a yaml document.
+func (controller *RootConf) Persist() error {
+
+	out, err := yaml.Marshal(controller)
+	if err != nil {
+		return err
+	}
+
+	file, err := os.OpenFile(ConfigFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		wwlog.Error("%s", err)
+		os.Exit(1)
+	}
+
+	defer file.Close()
+
+	_, err = file.WriteString(string(out)+"\n")
+	if err != nil {
+		wwlog.Error("Unable to write to warewulf.conf")
+		return err
+	}
+
+	return nil
+}