chore(gonf): first draft of the gonf lib with commands, files, packages and variables

10 files changed, 522 insertions, 0 deletions

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..3faf555
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.adyxax.org/adyxax/gonf/v2
+
+go 1.21.5
diff --git a/gonf/commands.go b/gonf/commands.go
new file mode 100644
index 0000000..b5a11ca
--- /dev/null
+++ b/gonf/commands.go
@@ -0,0 +1,95 @@
+package gonf
+
+import (
+	"bytes"
+	"log/slog"
+	"os/exec"
+)
+
+// ----- Globals ---------------------------------------------------------------
+var commands []*CommandPromise
+
+// ----- Init ------------------------------------------------------------------
+func init() {
+	commands = make([]*CommandPromise, 0)
+}
+
+// ----- Public ----------------------------------------------------------------
+func Command(cmd string, args ...string) *CommandPromise {
+	return CommandWithEnv([]string{}, cmd, args...)
+}
+
+func CommandWithEnv(env []string, cmd string, args ...string) *CommandPromise {
+	return &CommandPromise{
+		args:   args,
+		chain:  nil,
+		cmd:    cmd,
+		env:    env,
+		err:    nil,
+		Status: PROMISED,
+	}
+}
+
+type CommandPromise struct {
+	args   []string
+	chain  []Promise
+	cmd    string
+	env    []string
+	err    error
+	Status Status
+	Stdout bytes.Buffer
+	Stderr bytes.Buffer
+}
+
+func (c *CommandPromise) IfRepaired(p ...Promise) Promise {
+	c.chain = p
+	return c
+}
+
+func (c *CommandPromise) Promise() Promise {
+	commands = append(commands, c)
+	return c
+}
+
+func (c *CommandPromise) Resolve() {
+	cmd := exec.Command(c.cmd, c.args...)
+	for _, e := range c.env {
+		cmd.Env = append(cmd.Environ(), e)
+	}
+	cmd.Stdout = &c.Stdout
+	cmd.Stderr = &c.Stderr
+
+	if c.err = cmd.Run(); c.err != nil {
+		c.Status = BROKEN
+		slog.Error("command", "args", c.args, "cmd", c.cmd, "env", c.env, "err", c.err, "stdout", c.Stdout.String(), "stderr", c.Stderr.String(), "status", c.Status)
+		return
+	}
+	if c.Stdout.Len() == 0 && c.Stderr.Len() > 0 {
+		c.Status = BROKEN
+		slog.Error("command", "args", c.args, "cmd", c.cmd, "env", c.env, "stdout", c.Stdout.String(), "stderr", c.Stderr.String(), "status", c.Status)
+		return
+	}
+	c.Status = REPAIRED
+	slog.Info("command", "args", c.args, "cmd", c.cmd, "env", c.env, "stderr", c.Stderr.String(), "status", c.Status)
+	// TODO add a notion of repaired?
+	for _, p := range c.chain {
+		p.Resolve()
+	}
+}
+
+// ----- Internal --------------------------------------------------------------
+func resolveCommands() (status Status) {
+	status = KEPT
+	for _, c := range commands {
+		if c.Status == PROMISED {
+			c.Resolve()
+			switch c.Status {
+			case BROKEN:
+				return BROKEN
+			case REPAIRED:
+				status = REPAIRED
+			}
+		}
+	}
+	return
+}
diff --git a/gonf/files.go b/gonf/files.go
new file mode 100644
index 0000000..2401a25
--- /dev/null
+++ b/gonf/files.go
@@ -0,0 +1,153 @@
+package gonf
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"io"
+	"log/slog"
+	"net/url"
+	"os"
+	"text/template"
+)
+
+// ----- Globals ---------------------------------------------------------------
+var files []*FilePromise
+
+// ----- Init ------------------------------------------------------------------
+func init() {
+	files = make([]*FilePromise, 0)
+}
+
+// ----- Public ----------------------------------------------------------------
+func File(filename string, contents []byte) *FilePromise {
+	return &FilePromise{
+		chain:             nil,
+		contents:          contents,
+		err:               nil,
+		filename:          filename,
+		status:            PROMISED,
+		templateFunctions: nil,
+		useTemplate:       false,
+	}
+}
+
+type FilePromise struct {
+	chain             []Promise
+	contents          []byte
+	err               error
+	filename          string
+	status            Status
+	templateFunctions map[string]any
+	useTemplate       bool
+}
+
+func (f *FilePromise) IfRepaired(p ...Promise) Promise {
+	f.chain = p
+	return f
+}
+
+func (f *FilePromise) Promise() Promise {
+	files = append(files, f)
+	return f
+}
+
+func (f *FilePromise) Resolve() {
+	if f.useTemplate {
+		tpl := template.New(f.filename)
+		tpl.Option("missingkey=error")
+		tpl.Funcs(builtinTemplateFunctions)
+		tpl.Funcs(f.templateFunctions)
+		if ttpl, err := tpl.Parse(string(f.contents)); err != nil {
+			f.status = BROKEN
+			slog.Error("file", "filename", f.filename, "status", f.status, "error", f.err)
+			return
+		} else {
+			var buff bytes.Buffer
+			if err := ttpl.Execute(&buff, 0 /* TODO */); err != nil {
+				f.status = BROKEN
+				slog.Error("file", "filename", f.filename, "status", f.status, "error", f.err)
+				return
+			}
+			f.contents = buff.Bytes()
+		}
+	}
+	var sumFile []byte
+	sumFile, f.err = sha256sumOfFile(f.filename)
+	if f.err != nil {
+		f.status = BROKEN
+		return
+	}
+	sumContents := sha256sum(f.contents)
+	if !bytes.Equal(sumFile, sumContents) {
+		if f.err = writeFile(f.filename, f.contents); f.err != nil {
+			f.status = BROKEN
+			slog.Error("file", "filename", f.filename, "status", f.status, "error", f.err)
+			return
+		}
+		f.status = REPAIRED
+		slog.Info("file", "filename", f.filename, "status", f.status)
+		for _, p := range f.chain {
+			p.Resolve()
+		}
+		return
+	}
+	f.status = KEPT
+	slog.Debug("file", "filename", f.filename, "status", f.status)
+}
+
+func Template(filename string, contents []byte) *FilePromise {
+	f := File(filename, contents)
+	f.useTemplate = true
+	return f
+}
+
+func TemplateWith(filename string, contents []byte, templateFunctions map[string]any) *FilePromise {
+	f := Template(filename, contents)
+	f.templateFunctions = templateFunctions
+	return f
+}
+
+// ----- Internal --------------------------------------------------------------
+var builtinTemplateFunctions = map[string]any{
+	"encodeURIQueryParameter": url.QueryEscape,
+	"var":                     getVariable,
+}
+
+func resolveFiles() (status Status) {
+	status = KEPT
+	for _, f := range files {
+		if f.status == PROMISED {
+			f.Resolve()
+			switch f.status {
+			case BROKEN:
+				return BROKEN
+			case REPAIRED:
+				status = REPAIRED
+			}
+		}
+	}
+	return
+}
+
+func sha256sumOfFile(filename string) ([]byte, error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		return nil, err
+	}
+	return h.Sum(nil), nil
+}
+
+func writeFile(filename string, contents []byte) error {
+	f, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	_, err = f.Write(contents)
+	return err
+}
diff --git a/gonf/gonf.go b/gonf/gonf.go
new file mode 100644
index 0000000..b5aec4f
--- /dev/null
+++ b/gonf/gonf.go
@@ -0,0 +1,44 @@
+package gonf
+
+import (
+	"log/slog"
+	"os"
+)
+
+func EnableDebugLogs() {
+	h := slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+		Level: slog.LevelDebug,
+	})
+	slog.SetDefault(slog.New(h))
+}
+
+func Resolve() (status Status) {
+	for {
+		// ----- Files -------------------------------------------------
+		status = resolveFiles()
+		switch status {
+		case BROKEN:
+			return BROKEN
+		case REPAIRED:
+			continue
+		}
+		// ----- Packages ----------------------------------------------
+		status = resolvePackages()
+		switch status {
+		case BROKEN:
+			return BROKEN
+		case REPAIRED:
+			packages_list_function()
+			continue
+		}
+		// ----- Commands ----------------------------------------------
+		status = resolveCommands()
+		switch status {
+		case BROKEN:
+			return BROKEN
+		case REPAIRED:
+			continue
+		}
+		return
+	}
+}
diff --git a/gonf/packages.go b/gonf/packages.go
new file mode 100644
index 0000000..7ff512d
--- /dev/null
+++ b/gonf/packages.go
@@ -0,0 +1,73 @@
+package gonf
+
+// ----- Globals ---------------------------------------------------------------
+var packages []*PackagePromise
+
+// packages management functions
+var packages_install_function func([]string) Status
+var packages_list_function func()
+var packages_update_function *CommandPromise
+
+// ----- Init ------------------------------------------------------------------
+func init() {
+	packages = make([]*PackagePromise, 0)
+}
+
+// ----- Public ----------------------------------------------------------------
+func SetPackagesConfiguration(install func([]string) Status, list func(), update *CommandPromise) {
+	packages_install_function = install
+	packages_list_function = list
+	packages_update_function = update
+}
+
+func Package(names ...string) *PackagePromise {
+	return &PackagePromise{
+		chain:  nil,
+		err:    nil,
+		names:  names,
+		status: PROMISED,
+	}
+}
+
+type PackagePromise struct {
+	chain  []Promise
+	err    error
+	names  []string
+	status Status
+}
+
+func (p *PackagePromise) IfRepaired(ps ...Promise) Promise {
+	p.chain = ps
+	return p
+}
+
+func (p *PackagePromise) Promise() Promise {
+	packages = append(packages, p)
+	return p
+}
+
+func (p *PackagePromise) Resolve() {
+	status := packages_install_function(p.names)
+	if status == REPAIRED {
+		for _, pp := range p.chain {
+			pp.Resolve()
+		}
+	}
+}
+
+// ----- Internal --------------------------------------------------------------
+func resolvePackages() (status Status) {
+	status = KEPT
+	for _, c := range packages {
+		if c.status == PROMISED {
+			c.Resolve()
+			switch c.status {
+			case BROKEN:
+				return BROKEN
+			case REPAIRED:
+				status = REPAIRED
+			}
+		}
+	}
+	return
+}
diff --git a/gonf/promises.go b/gonf/promises.go
new file mode 100644
index 0000000..326d500
--- /dev/null
+++ b/gonf/promises.go
@@ -0,0 +1,50 @@
+package gonf
+
+type Promise interface {
+	IfRepaired(...Promise) Promise
+	Promise() Promise
+	Resolve()
+}
+
+//type Operation int
+//
+//const (
+//	AND = iota
+//	OR
+//	NOT
+//)
+//
+//func (o Operation) String() string {
+//	switch o {
+//	case AND:
+//		return "and"
+//	case OR:
+//		return "or"
+//	case NOT:
+//		return "not"
+//	}
+//	panic("unknown")
+//}
+
+type Status int
+
+const (
+	PROMISED = iota
+	BROKEN
+	KEPT
+	REPAIRED
+)
+
+func (s Status) String() string {
+	switch s {
+	case PROMISED:
+		return "promised"
+	case BROKEN:
+		return "broken"
+	case KEPT:
+		return "kept"
+	case REPAIRED:
+		return "repaired"
+	}
+	panic("unknown")
+}
diff --git a/gonf/triggers.go b/gonf/triggers.go
new file mode 100644
index 0000000..370ab1c
--- /dev/null
+++ b/gonf/triggers.go
@@ -0,0 +1,11 @@
+package gonf
+
+type simpleTrigger struct {
+	fact   string
+	status Status
+}
+
+//type compositeTrigger struct {
+//	triggers  []simpleTrigger
+//	operation Operation
+//}
diff --git a/gonf/utils.go b/gonf/utils.go
new file mode 100644
index 0000000..7031062
--- /dev/null
+++ b/gonf/utils.go
@@ -0,0 +1,9 @@
+package gonf
+
+import "crypto/sha256"
+
+func sha256sum(contents []byte) []byte {
+	h := sha256.New()
+	h.Write(contents)
+	return h.Sum(nil)
+}
diff --git a/gonf/values.go b/gonf/values.go
new file mode 100644
index 0000000..15c109b
--- /dev/null
+++ b/gonf/values.go
@@ -0,0 +1,27 @@
+package gonf
+
+type Value interface {
+	Equals(Value) bool
+	String() string
+}
+
+// ----- String variables ------------------------------------------------------
+type StringValue struct {
+	Value string
+}
+
+func (s StringValue) Equals(v Value) bool {
+	sv, ok := v.(StringValue)
+	return ok && s.Value == sv.Value
+}
+
+func (s StringValue) String() string {
+	// TODO handle interpolation
+	return s.Value
+}
+
+// TODO lists
+
+// TODO maps
+
+// TODO what else?
diff --git a/gonf/variables.go b/gonf/variables.go
new file mode 100644
index 0000000..3c365ae
--- /dev/null
+++ b/gonf/variables.go
@@ -0,0 +1,57 @@
+package gonf
+
+import "log/slog"
+
+// ----- Globals ---------------------------------------------------------------
+var variables map[string]*VariablePromise
+
+// ----- Init ------------------------------------------------------------------
+func init() {
+	variables = make(map[string]*VariablePromise)
+}
+
+// ----- Public ----------------------------------------------------------------
+func Default(name string, value Value) *VariablePromise {
+	if v, ok := variables[name]; ok {
+		if !v.isDefault {
+			slog.Debug("default would overwrite a variable, ignoring", "name", name, "old_value", v.value, "new_value", value)
+			return nil
+		}
+		slog.Error("default is being overwritten", "name", name, "old_value", v.value, "new_value", value)
+	}
+	v := &VariablePromise{
+		isDefault: true,
+		name:      name,
+		value:     value,
+	}
+	variables[name] = v
+	return v
+}
+func Variable(name string, value Value) *VariablePromise {
+	if v, ok := variables[name]; ok && !v.isDefault {
+		slog.Error("variable is being overwritten", "name", name, "old_value", v, "new_value", value)
+	}
+	v := &VariablePromise{
+		isDefault: false,
+		name:      name,
+		value:     value,
+	}
+	variables[name] = v
+	return v
+}
+
+type VariablePromise struct {
+	isDefault bool
+	name      string
+	value     Value
+}
+
+// ----- Internal --------------------------------------------------------------
+func getVariable(name string) string {
+	if v, ok := variables[name]; ok {
+		return v.value.String()
+	} else {
+		slog.Error("undefined variable or default", "name", name)
+		return name
+	}
+}