ceph: add NewConfigFromReader() and initial ceph.conf parser

Signed-off-by: Alejandro Mery <amery@jpi.io>

go.mod

@@ -3,6 +3,7 @@ module git.jpi.io/amery/jpictl
 go 1.19
 
 require (
+	asciigoat.org/ini v0.2.5
 	darvaza.org/core v0.9.8
 	darvaza.org/resolver v0.5.4
 	darvaza.org/sidecar v0.0.2
@@ -18,6 +19,7 @@ require (
 )
 
 require (
+	asciigoat.org/core v0.3.9 // indirect
 	darvaza.org/slog/handlers/filter v0.4.5 // indirect
 	darvaza.org/slog/handlers/zerolog v0.4.5 // indirect
 	github.com/BurntSushi/toml v1.3.2 // indirect

go.sum

@@ -1,3 +1,7 @@
+asciigoat.org/core v0.3.9 h1:hgDDz4ecm3ZvehX++m8A/IzAt+B5oDPiRtxatzfUHPQ=
+asciigoat.org/core v0.3.9/go.mod h1:CAaHwyw8MpAq4a1MYtN2dxJrsK+hmIdW50OndaQZYPI=
+asciigoat.org/ini v0.2.5 h1:4gRIp9rU+XQt8+HMqZO5R7GavMv9Yl2+N+je6djDIAE=
+asciigoat.org/ini v0.2.5/go.mod h1:gmXzJ9XFqf1NLk5nQkj04USQ4tMtdRJHNQX6vp3DzjU=
 darvaza.org/core v0.9.8 h1:luLxgfUc2pzuusYPo/Z/dC/qr9XZPKpSQw8/kS7zNUM=
 darvaza.org/core v0.9.8/go.mod h1:Dbme64naxeshQfxcVJX9ZT7AiGyIY8kldfuELVtf8mw=
 darvaza.org/resolver v0.5.4 h1:dlSBNV14yYsp7Kg7ipwYOMNsLbrpeXa8Z0HBTa0Ryxs=

pkg/ceph/ceph.go

@@ -0,0 +1,2 @@
+// Package ceph deals with ceph config
+package ceph

pkg/ceph/config.go

@@ -0,0 +1,38 @@
+package ceph
+
+import (
+	"io"
+	"net/netip"
+
+	"github.com/gofrs/uuid/v5"
+
+	"asciigoat.org/ini/basic"
+)
+
+// Config represents a ceph.conf file
+type Config struct {
+	Global GlobalConfig `ini:"global"`
+}
+
+// GlobalConfig represents the [global] section of a ceph.conf file
+type GlobalConfig struct {
+	FSID           uuid.UUID    `ini:"fsid"`
+	Monitors       []string     `ini:"mon_initial_members,comma"`
+	MonitorsAddr   []netip.Addr `ini:"mon_host,comma"`
+	ClusterNetwork netip.Prefix `ini:"cluster_network"`
+}
+
+// NewConfigFromReader parses the ceph.conf file
+func NewConfigFromReader(r io.Reader) (*Config, error) {
+	doc, err := basic.Decode(r)
+	if err != nil {
+		return nil, err
+	}
+
+	cfg, err := newConfigFromDocument(doc)
+	if err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
+}

pkg/ceph/config_parser.go

@@ -0,0 +1,110 @@
+package ceph
+
+import (
+	"io/fs"
+	"net/netip"
+
+	"asciigoat.org/ini/basic"
+	"asciigoat.org/ini/parser"
+
+	"darvaza.org/core"
+)
+
+var sectionMap = map[string]func(*Config, *basic.Section) error{
+	"global": loadGlobalConfSection,
+}
+
+func loadConfSection(out *Config, src *basic.Section) error {
+	h, ok := sectionMap[src.Key]
+	if !ok {
+		return core.Wrapf(fs.ErrInvalid, "unknown section %q", src.Key)
+	}
+
+	return h(out, src)
+}
+
+func loadGlobalConfSection(out *Config, src *basic.Section) error {
+	var cfg GlobalConfig
+
+	for _, field := range src.Fields {
+		if err := loadGlobalConfField(&cfg, field); err != nil {
+			return core.Wrap(err, "global")
+		}
+	}
+
+	out.Global = cfg
+	return nil
+}
+
+// revive:disable:cyclomatic
+// revive:disable:cognitive-complexity
+
+func loadGlobalConfField(cfg *GlobalConfig, field basic.Field) error {
+	// revive:enable:cyclomatic
+	// revive:enable:cognitive-complexity
+
+	// TODO: refactor when asciigoat's ini parser learns to do reflection
+
+	switch field.Key {
+	case "fsid":
+		if !core.IsZero(cfg.FSID) {
+			return core.Wrapf(fs.ErrInvalid, "duplicate field %q", field.Key)
+		}
+
+		err := cfg.FSID.UnmarshalText([]byte(field.Value))
+		switch {
+		case err != nil:
+			return core.Wrap(err, field.Key)
+		default:
+			return nil
+		}
+	case "mon_host":
+		entries, _ := parser.SplitCommaArray(field.Value)
+		for _, s := range entries {
+			var addr netip.Addr
+
+			if err := addr.UnmarshalText([]byte(s)); err != nil {
+				return core.Wrap(err, field.Key)
+			}
+
+			cfg.MonitorsAddr = append(cfg.MonitorsAddr, addr)
+		}
+		return nil
+	case "mon_initial_members":
+		entries, _ := parser.SplitCommaArray(field.Value)
+		cfg.Monitors = append(cfg.Monitors, entries...)
+		return nil
+	case "cluster_network":
+		if !core.IsZero(cfg.ClusterNetwork) {
+			err := core.Wrap(fs.ErrInvalid, "fields before the first section")
+			return err
+		}
+
+		err := cfg.ClusterNetwork.UnmarshalText([]byte(field.Value))
+		switch {
+		case err != nil:
+			return core.Wrap(err, field.Key)
+		default:
+			return nil
+		}
+	}
+	return nil
+}
+
+func newConfigFromDocument(doc *basic.Document) (*Config, error) {
+	var out Config
+
+	if len(doc.Global) > 0 {
+		err := core.Wrap(fs.ErrInvalid, "fields before the first section")
+		return nil, err
+	}
+
+	for i := range doc.Sections {
+		src := &doc.Sections[i]
+		if err := loadConfSection(&out, src); err != nil {
+			return nil, err
+		}
+	}
+
+	return &out, nil
+}