php: Move server code into new phpx package

internal/phpx/errors.go

@@ -1,14 +1,12 @@
-package phpserver
+package phpx
 
 import "fmt"
 
 // Common PHP Errors
-var (
+const (
-	errPHPInit    = "Unable to initialize"
+	errInit    = "Server initialization failed"
-	errPHPMarshal = "Marshal failed"
+	errClosed  = "Server closed"
-	errPHPInvalid = ServerError{Message: "Invalid code to execute"}
+	errReceive = "Failed to decode response"
-	errPHPReceive = "Failed to receive response"
-	errPHPClosed  = ServerError{Message: "Server closed"}
 )
 
 // PHPError represents an error during PHPServer logic
@@ -17,6 +15,7 @@ type ServerError struct {
 	Err     error
 }
 
+// Unwrap returns the underlying error
 func (err ServerError) Unwrap() error {
 	return err.Err
 }

internal/phpx/marshal.go

@@ -1,4 +1,4 @@
-package phpserver
+package phpx
 
 import (
 	"encoding/json"

internal/phpx/php.go

@@ -0,0 +1,18 @@
+// Package phpx provides functionalities for interacting with PHP code
+package phpx
+
+import "github.com/tkw1536/goprogram/stream"
+
+// Executor represents anything that can spawn
+type Executor interface {
+	// Spawn spawns a new (independent) process executing code.
+	// It should return only once the execution terminates.
+	Spawn(str stream.IOStream, code string) error
+}
+
+// SpawnFunc implements Executor
+type SpawnFunc func(str stream.IOStream, code string) error
+
+func (sf SpawnFunc) Spawn(str stream.IOStream, code string) error {
+	return sf(str, code)
+}

internal/phpx/server.go

@@ -1,4 +1,4 @@
-package phpserver
+package phpx
 
 import (
 	"context"
@@ -10,62 +10,78 @@ import (
 
 	_ "embed"
 
+	"github.com/FAU-CDI/wisski-distillery/pkg/lazy"
 	"github.com/tkw1536/goprogram/lib/collection"
 	"github.com/tkw1536/goprogram/lib/nobufio"
 	"github.com/tkw1536/goprogram/stream"
 )
 
-// New creates a new server, with execPHP as a method to call a PHP Shell.
+// Server represents a server that executes PHP code.
-func New(execPHP func(str stream.IOStream, script string)) (*Server, error) {
-	// create input and output pipes
-	ir, iw, err := os.Pipe()
-	if err != nil {
-		return nil, ServerError{errPHPInit, err}
-	}
-	or, ow, err := os.Pipe()
-	if err != nil {
-		ir.Close()
-		iw.Close()
-		return nil, ServerError{errPHPInit, err}
-	}
-
-	// create a context to close the server
-	context, cancel := context.WithCancel(context.Background())
-
-	// start the shell process, which will close everything once done
-	go func() {
-		defer func() {
-			ir.Close()
-			iw.Close()
-			or.Close()
-			ow.Close()
-
-			cancel()
-		}()
-
-		// start the server
-		io := stream.NewIOStream(ow, nil, ir, 0)
-		execPHP(io, serverPHP)
-	}()
-
-	// return a new server
-	return &Server{
-		in:  iw,
-		out: or,
-		c:   context,
-	}, nil
-}
-
-// Server represents a server that executes code within a distillery.
 // A typical use-case is to define functions using [MarshalEval], and then call those functions [MarshalCall].
 //
-// A nil Server will return [ErrServerBroken] on every function call.
+// A server, once used, should be closed using the [Close] method.
 type Server struct {
-	m sync.Mutex
+	// Executor is the executor used by this server.
+	// It may not be modified concurrently with other processes.
+	Executor Executor
 
+	// prepares the server
+	init sync.Once
+	err  lazy.Lazy[error]
+
+	// input / output for underlying executor
 	in  io.WriteCloser
 	out io.Reader
-	c   context.Context
+
+	m sync.Mutex // prevents concurrent access on any of the methods
+
+	c context.Context // closed when server is finished
+
+}
+
+func (server *Server) prepare() error {
+	server.init.Do(func() {
+		// create input and output pipes
+		ir, iw, err := os.Pipe()
+		if err != nil {
+			server.err.Set(ServerError{errInit, err})
+			return
+		}
+		or, ow, err := os.Pipe()
+		if err != nil {
+			ir.Close()
+			iw.Close()
+
+			server.err.Set(ServerError{errInit, err})
+			return
+		}
+
+		// create a context to close the server
+		context, cancel := context.WithCancel(context.Background())
+
+		// start the shell process, which will close everything once done
+		go func() {
+			defer func() {
+				ir.Close()
+				iw.Close()
+				or.Close()
+				ow.Close()
+
+				cancel()
+			}()
+
+			// start the server
+			io := stream.NewIOStream(ow, nil, ir, 0)
+			err := server.Executor.Spawn(io, serverPHP)
+			server.err.Set(ServerError{errClosed, err})
+		}()
+
+		server.in = iw
+		server.out = or
+		server.c = context
+	})
+
+	return server.err.Get(nil)
 }
 
 // MarshalEval evaluates code on the server and Marshals the result into value.
@@ -76,28 +92,35 @@ type Server struct {
 //
 // When an exception is thrown by the PHP Code, error is not nil, and dest remains unchanged.
 func (server *Server) MarshalEval(value any, code string) error {
+	if err := server.prepare(); err != nil {
+		return err
+	}
+
+	// input to be sent to the server
+	delim := findDelimiter(code)
+	input := delim + "\n" + code + "\n" + delim + "\n"
+
 	server.m.Lock()
 	defer server.m.Unlock()
 
-	// quick hack: when the server is already done
+	// when the server is already done
 	if err := server.c.Err(); err != nil {
-		return errPHPClosed
+		return ServerError{Message: errClosed}
 	}
 
 	// find a delimiter for the code, and then send
-	delim := findDelimiter(code)
+	io.WriteString(server.in, input)
-	io.WriteString(server.in, delim+"\n"+code+"\n"+delim+"\n")
 
 	// read the next line (as a response)
 	data, err := nobufio.ReadLine(server.out)
 	if err != nil {
-		return ServerError{Message: errPHPReceive, Err: err}
+		return ServerError{Message: errReceive, Err: err}
 	}
 
 	// read whatever we received
 	var received [2]json.RawMessage
 	if err := json.Unmarshal([]byte(data), &received); err != nil {
-		return ServerError{Message: errPHPMarshal, Err: err}
+		return ServerError{Message: errReceive, Err: err}
 	}
 
 	// check if there was an error
@@ -126,7 +149,6 @@ func (server *Server) Eval(code string) (value any, err error) {
 //
 // Return values are received as in [MarshalEval].
 func (server *Server) MarshalCall(value any, function string, args ...any) error {
-
 	// name of function to call
 	name := MarshalString(function)
 
@@ -182,12 +204,14 @@ func findDelimiter(input string) string {
 
 // Close closes this server and prevents any further code from being run.
 func (server *Server) Close() error {
+	server.prepare()
+
 	server.m.Lock()
 	defer server.m.Unlock()
 
 	// if the context is already closed
 	if err := server.c.Err(); err != nil {
-		return errPHPClosed
+		return ServerError{Message: errClosed}
 	}
 
 	server.in.Close()

internal/wisski/ingredient/barrel/drush/cron.go

@@ -3,8 +3,8 @@ package drush
 import (
 	"time"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
-	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php"
 	"github.com/tkw1536/goprogram/exit"
 	"github.com/tkw1536/goprogram/stream"
 )
@@ -28,7 +28,7 @@ func (drush *Drush) Cron(io stream.IOStream) error {
 	return nil
 }
 
-func (drush *Drush) LastCron(server *php.Server) (t time.Time, err error) {
+func (drush *Drush) LastCron(server *phpx.Server) (t time.Time, err error) {
 	var timestamp int64
 	err = drush.PHP.EvalCode(server, &timestamp, `$val = \Drupal::state()->get('system.cron_last'); return $val; `)
 	if err != nil {

internal/wisski/ingredient/fetcher.go

@@ -4,7 +4,7 @@ import (
 	"time"
 
 	"github.com/FAU-CDI/wisski-distillery/internal/models"
-	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php/phpserver"
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 )
 
 // Fetcher is an ingredient with a fetch method
@@ -19,7 +19,7 @@ type Fetcher interface {
 // FetchFlags specifies what information to fetch
 type FetchFlags struct {
 	Quick  bool
-	Server *phpserver.Server
+	Server *phpx.Server
 }
 
 // Information represents fetched information about a WissKI

internal/wisski/ingredient/info/info.go

@@ -38,9 +38,9 @@ func (wisski *Info) Information(quick bool) (info WissKIInfo, err error) {
 
 	// potentially setup a new server
 	if !flags.Quick {
-		server, err := wisski.PHP.NewServer()
+		flags.Server = wisski.PHP.NewServer()
 		if err == nil {
-			defer server.Close()
+			defer flags.Server.Close()
 		}
 	}
 

internal/wisski/ingredient/php/extras/pathbuilder.go

@@ -3,6 +3,7 @@ package extras
 import (
 	_ "embed"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php"
 	"golang.org/x/exp/slices"
@@ -20,7 +21,7 @@ var pathbuilderPHP string
 // All returns the ids of all pathbuilders in consistent order.
 //
 // server is the server to fetch the pathbuilders from, any may be nil.
-func (pathbuilder *Pathbuilder) All(server *php.Server) (ids []string, err error) {
+func (pathbuilder *Pathbuilder) All(server *phpx.Server) (ids []string, err error) {
 	err = pathbuilder.PHP.ExecScript(server, &ids, pathbuilderPHP, "all_list")
 	slices.Sort(ids)
 	return
@@ -30,7 +31,7 @@ func (pathbuilder *Pathbuilder) All(server *php.Server) (ids []string, err error
 // If it does not exist, it returns the empty string and nil error.
 //
 // server is the server to fetch the pathbuilders from, any may be nil.
-func (pathbuilder *Pathbuilder) Get(server *php.Server, id string) (xml string, err error) {
+func (pathbuilder *Pathbuilder) Get(server *phpx.Server, id string) (xml string, err error) {
 	err = pathbuilder.PHP.ExecScript(server, &xml, pathbuilderPHP, "one_xml", id)
 	return
 }
@@ -38,7 +39,7 @@ func (pathbuilder *Pathbuilder) Get(server *php.Server, id string) (xml string,
 // GetAll returns all pathbuilders serialized as xml
 //
 // server is the server to fetch the pathbuilders from, any may be nil.
-func (pathbuilder *Pathbuilder) GetAll(server *php.Server) (pathbuilders map[string]string, err error) {
+func (pathbuilder *Pathbuilder) GetAll(server *phpx.Server) (pathbuilders map[string]string, err error) {
 	err = pathbuilder.PHP.ExecScript(server, &pathbuilders, pathbuilderPHP, "all_xml")
 	return
 }

internal/wisski/ingredient/php/extras/prefixes.go

@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/mstore"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php"
@@ -35,7 +36,7 @@ var listURIPrefixesPHP string
 //
 // server is an optional server to fetch prefixes from.
 // server may be nil.
-func (prefixes *Prefixes) All(server *php.Server) ([]string, error) {
+func (prefixes *Prefixes) All(server *phpx.Server) ([]string, error) {
 	uris, err := prefixes.database(server)
 	if err != nil {
 		return nil, err
@@ -49,7 +50,7 @@ func (prefixes *Prefixes) All(server *php.Server) ([]string, error) {
 	return append(uris, uris2...), nil
 }
 
-func (wisski *Prefixes) database(server *php.Server) (prefixes []string, err error) {
+func (wisski *Prefixes) database(server *phpx.Server) (prefixes []string, err error) {
 	// get all the ugly prefixes
 	err = wisski.PHP.ExecScript(server, &prefixes, listURIPrefixesPHP, "list_prefixes")
 	if err != nil {

internal/wisski/ingredient/php/extras/settings.go

@@ -3,6 +3,7 @@ package extras
 import (
 	_ "embed"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php"
 )
@@ -16,11 +17,11 @@ type Settings struct {
 //go:embed settings.php
 var settingsPHP string
 
-func (settings *Settings) Get(server *php.Server, key string) (value any, err error) {
+func (settings *Settings) Get(server *phpx.Server, key string) (value any, err error) {
 	err = settings.PHP.ExecScript(server, &value, settingsPHP, "get_setting", key)
 	return
 }
 
-func (settings *Settings) Set(server *php.Server, key string, value any) error {
+func (settings *Settings) Set(server *phpx.Server, key string, value any) error {
 	return settings.PHP.ExecScript(server, nil, settingsPHP, "set_setting", key, value)
 }

internal/wisski/ingredient/php/php.go

@@ -3,6 +3,7 @@ package php
 import (
 	"strings"
 
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient"
 	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/barrel"
 )
@@ -27,9 +28,9 @@ type PHP struct {
 // It's arguments are encoded as json using [json.Marshal] and decoded within php.
 //
 // The return value of the function is again marshaled with json and returned to the caller.
-func (php *PHP) ExecScript(server *Server, value any, code string, entrypoint string, args ...any) (err error) {
+func (php *PHP) ExecScript(server *phpx.Server, value any, code string, entrypoint string, args ...any) (err error) {
 	if server == nil {
-		server, err = php.NewServer()
+		server = php.NewServer()
 		if err != nil {
 			return
 		}
@@ -45,9 +46,9 @@ func (php *PHP) ExecScript(server *Server, value any, code string, entrypoint st
 	return server.MarshalCall(value, entrypoint, args...)
 }
 
-func (php *PHP) EvalCode(server *Server, value any, code string) (err error) {
+func (php *PHP) EvalCode(server *phpx.Server, value any, code string) (err error) {
 	if server == nil {
-		server, err = php.NewServer()
+		server = php.NewServer()
 		if err != nil {
 			return
 		}

internal/wisski/ingredient/php/server.go

@@ -3,19 +3,22 @@ package php
 import (
 	_ "embed"
 
-	"github.com/FAU-CDI/wisski-distillery/internal/wisski/ingredient/php/phpserver"
+	"github.com/FAU-CDI/wisski-distillery/internal/phpx"
 	"github.com/alessio/shellescape"
 	"github.com/tkw1536/goprogram/stream"
 )
 
-type Server = phpserver.Server
-
 // NewServer returns a new server that can execute code within this distillery.
 // When err == nil, the caller must call server.Close().
 //
 // See [PHPServer].
-func (php *PHP) NewServer() (*Server, error) {
+func (php *PHP) NewServer() *phpx.Server {
-	return phpserver.New(func(str stream.IOStream, script string) {
+	return &phpx.Server{
-		php.Barrel.Shell(str, "-c", shellescape.QuoteCommand([]string{"drush", "php:eval", script}))
+		Executor: phpx.SpawnFunc(php.spawn),
-	})
+	}
+}
+
+func (php *PHP) spawn(str stream.IOStream, code string) error {
+	_, err := php.Barrel.Shell(str, "-c", shellescape.QuoteCommand([]string{"drush", "php:eval", code}))
+	return err
 }