Add native Python SDK configuration (python version, uv, base image)

.dagger/lock

@@ -1,2 +1,3 @@
 [["version","1"]]
-["","git.head",["https://github.com/dagger/sdk-sdk"],"d6ab6406586e6b3853b8936b2b3a96bba2554071","float"]
+["","container.from",["docker.io/library/golang:1.25-alpine","linux/arm64"],"sha256:8d22e29d960bc50cd025d93d5b7c7d220b1ee9aa7a239b3c8f55a57e987e8d45","pin"]
+["","git.head",["https://github.com/dagger/sdk-sdk"],"09da9576688ec4b495ae4a9443a4719da86ed25e","float"]

.dagger/modules/e2e/fixtures/config/app/dagger.json

@@ -0,0 +1,7 @@
+{
+  "name": "config-app",
+  "engineVersion": "latest",
+  "sdk": {
+    "source": "python"
+  }
+}

.dagger/modules/e2e/fixtures/config/app/pyproject.toml

@@ -0,0 +1,12 @@
+[project]
+name = "config-app"
+version = "0.1.0"
+requires-python = ">=3.14"
+dependencies = ["dagger-io"]
+
+[build-system]
+requires = ["uv_build>=0.8.4,<0.9.0"]
+build-backend = "uv_build"
+
+[tool.uv.sources]
+dagger-io = { path = "sdk", editable = true }

.dagger/modules/e2e/fixtures/config/app/src/config_app/__init__.py

@@ -0,0 +1,10 @@
+import dagger
+from dagger import object_type
+
+
+@object_type
+class ConfigApp:
+    source: dagger.Directory
+
+    def __init__(self, ws: dagger.Workspace):
+        self.source = ws.directory("/")

.dagger/modules/e2e/fixtures/config/configured/dagger.json

@@ -0,0 +1,7 @@
+{
+  "name": "config-configured",
+  "engineVersion": "latest",
+  "sdk": {
+    "source": "python"
+  }
+}

.dagger/modules/e2e/fixtures/config/configured/pyproject.toml

@@ -0,0 +1,16 @@
+[project]
+name = "config-configured"
+version = "0.1.0"
+requires-python = ">=3.12"
+dependencies = ["dagger-io"]
+
+[build-system]
+requires = ["uv_build>=0.8.4,<0.9.0"]
+build-backend = "uv_build"
+
+[tool.dagger]
+use-uv = false
+base-image = "python:3.12-slim"
+
+[tool.uv.sources]
+dagger-io = { path = "sdk", editable = true }

.dagger/modules/e2e/fixtures/config/configured/src/config_configured/__init__.py

@@ -0,0 +1,10 @@
+import dagger
+from dagger import object_type
+
+
+@object_type
+class ConfigConfigured:
+    source: dagger.Directory
+
+    def __init__(self, ws: dagger.Workspace):
+        self.source = ws.directory("/")

.dagger/modules/e2e/main.dang

@@ -11,6 +11,8 @@ type E2e {
   let skipModulePath: String! = fixtureRoot + "/skip/app"
   let generateModulePath: String! = fixtureRoot + "/generate/app"
   let depsModulePath: String! = fixtureRoot + "/deps/app"
+  let configModulePath: String! = fixtureRoot + "/config/app"
+  let configuredModulePath: String! = fixtureRoot + "/config/configured"
 
   let generatedMarkerPath: String! = "sdk/src/dagger/client/gen.py"
   let generatedMarkerContents: String! = "Code generated by dagger."
@@ -222,4 +224,74 @@ type E2e {
 
     null
   }
+
+  """
+  config.get should reflect pyproject.toml and report unset values as null
+  rather than guessing, and config.set should edit only pyproject.toml.
+  """
+  pub configCheck(ws: Workspace!): Void @check {
+    let app = pythonSdk.mod(ws, path: configModulePath).config
+    let configured = pythonSdk.mod(ws, path: configuredModulePath).config
+
+    let appValues = app.get
+    assert(appValues.pythonVersion == "3.14", "default pythonVersion should read 3.14")
+    assert(appValues.useUv == null, "useUv should be reported as unset, not guessed")
+    assert(appValues.baseImage == null, "baseImage should be reported as unset")
+
+    let configuredValues = configured.get
+    assert(configuredValues.pythonVersion == "3.12", "configured pythonVersion should read 3.12")
+    assert(configuredValues.useUv == false, "configured useUv should read false")
+    assert(configuredValues.baseImage == "python:3.12-slim", "configured baseImage should read the override")
+
+    let pyproj = configModulePath + "/pyproject.toml"
+
+    let py = app.set(pythonVersion: "3.13")
+    assert(contains(py.modifiedPaths, pyproj), "set should modify pyproject.toml")
+    assert(py.modifiedPaths.length == 1, "set modified more than pyproject.toml")
+    assert(py.addedPaths.length == 0, "set should not add files")
+    assertContains(py.after.file(pyproj).contents, ">=3.13", "set did not write the new python version")
+    assertContains(py.after.file(pyproj).contents, "dagger-io", "set dropped unrelated keys")
+
+    let multi = app.set(pythonVersion: "3.13", useUv: false, baseImage: "python:3.13-slim")
+    assert(multi.modifiedPaths.length == 1, "multi-value set modified more than pyproject.toml")
+    assert(multi.addedPaths.length == 0, "multi-value set should not add files")
+    assertContains(multi.after.file(pyproj).contents, ">=3.13", "multi-value set did not write python version")
+    assertContains(multi.after.file(pyproj).contents, "use-uv = false", "multi-value set did not write use-uv")
+    assertContains(multi.after.file(pyproj).contents, "python:3.13-slim", "multi-value set did not write base image")
+
+    let configuredPyproj = configuredModulePath + "/pyproject.toml"
+    let partial = configured.set(pythonVersion: "3.13")
+    assertContains(partial.after.file(configuredPyproj).contents, ">=3.13", "partial set did not update python version")
+    assertContains(partial.after.file(configuredPyproj).contents, "use-uv = false", "omitting useUv should leave it untouched")
+    assertContains(partial.after.file(configuredPyproj).contents, "python:3.12-slim", "omitting baseImage should leave it untouched")
+
+    null
+  }
+
+  """
+  Init flags should write configuration into the generated pyproject.toml, and
+  defaults should leave it unconfigured.
+  """
+  pub initConfigCheck(ws: Workspace!): Void @check {
+    let configuredPath = outputRoot + "/init-configured"
+    let defaultPath = outputRoot + "/init-config-default"
+
+    let configured = pythonSdk.init(ws, name: "init-configured", path: configuredPath, pythonVersion: "3.13", useUv: false, baseImage: "python:3.13-slim")
+    let pyproj = configuredPath + "/pyproject.toml"
+    assertAdded(configured, pyproj)
+    assert(configured.modifiedPaths.length == 0, "configured init should not modify existing files")
+    assert(configured.removedPaths.length == 0, "configured init should not remove files")
+    assertContains(configured.layer.file(pyproj).contents, ">=3.13", "init --python-version not written")
+    assertContains(configured.layer.file(pyproj).contents, "use-uv = false", "init --use-uv=false not written")
+    assertContains(configured.layer.file(pyproj).contents, "python:3.13-slim", "init --base-image not written")
+    assertContains(configured.layer.file(pyproj).contents, "dagger-io", "init config dropped template data")
+
+    let default = pythonSdk.init(ws, name: "init-config-default", path: defaultPath)
+    let defaultPyproj = defaultPath + "/pyproject.toml"
+    assertContains(default.layer.file(defaultPyproj).contents, ">=3.14", "default init should keep the template python version")
+    assertNotContains(default.layer.file(defaultPyproj).contents, "use-uv", "default init should not write use-uv")
+    assertNotContains(default.layer.file(defaultPyproj).contents, "[tool.dagger]", "default init should not write a [tool.dagger] table")
+
+    null
+  }
 }

README.md

@@ -45,6 +45,47 @@ dagger call python-sdk init --name my-module --template legacy
 `init` only seeds template files. Run `mod ... generate` to produce the
 generated SDK.
 
+### Configure a module at creation
+
+`init` accepts configuration flags written into the module's `pyproject.toml`:
+
+```sh
+dagger call python-sdk init --name my-module \
+    --python-version 3.13 \
+    --use-uv=false \
+    --base-image python:3.13-slim
+```
+
+All three are optional. By default the template's Python version is used, uv is
+enabled, and no base image override is written.
+
+## Configure an existing module
+
+Read the current configuration. Settings that are not explicitly written to
+`pyproject.toml` are reported as `null` rather than guessed:
+
+```sh
+dagger call python-sdk mod --path my-module config get
+```
+
+Select a single value:
+
+```sh
+dagger call python-sdk mod --path my-module config get python-version
+dagger call python-sdk mod --path my-module config get use-uv
+dagger call python-sdk mod --path my-module config get base-image
+```
+
+Change one or more values at once (prints a diff to confirm before writing).
+Each flag is optional; omitting one leaves that setting untouched:
+
+```sh
+dagger call python-sdk mod --path my-module config set \
+    --python-version 3.13 \
+    --use-uv=false \
+    --base-image python:3.13-slim
+```
+
 ## Generate SDK files
 
 For a single module:

dagger.json

@@ -1,14 +1,14 @@
 {
   "name": "python-sdk",
-  "engineVersion": "v0.20.8",
+  "engineVersion": "v0.21.3",
   "sdk": {
     "source": "dang"
   },
   "dependencies": [
     {
       "name": "polyfill",
       "source": "https://github.com/dagger/sdk-sdk/polyfill@main",
-      "pin": "d6ab6406586e6b3853b8936b2b3a96bba2554071"
+      "pin": "09da9576688ec4b495ae4a9443a4719da86ed25e"
     }
   ]
 }

helpers/pyproject/go.mod

@@ -0,0 +1,5 @@
+module pyproject
+
+go 1.25.0
+
+require github.com/pelletier/go-toml/v2 v2.3.1

helpers/pyproject/go.sum

@@ -0,0 +1,2 @@
+github.com/pelletier/go-toml/v2 v2.3.1 h1:MYEvvGnQjeNkRF1qUuGolNtNExTDwct51yp7olPtrEc=
+github.com/pelletier/go-toml/v2 v2.3.1/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=

helpers/pyproject/main.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+// run dispatches a subcommand. get-* commands print to stdout (no trailing
+// newline). set-* commands edit the file in place.
+//
+// usage: pyproject <command> <file> [value]
+func run(args []string) error {
+	if len(args) < 2 {
+		return fmt.Errorf("usage: pyproject <command> <file> [value]")
+	}
+	cmd, path := args[0], args[1]
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	doc, err := load(data)
+	if err != nil {
+		return err
+	}
+
+	switch cmd {
+	case "get-python-version":
+		fmt.Print(getPythonVersion(doc))
+		return nil
+	case "get-use-uv":
+		// Print nothing when unset so callers can tell an absent setting from
+		// an explicit value, instead of guessing the true default.
+		if v, ok := getUseUv(doc); ok {
+			fmt.Print(boolStr(v))
+		}
+		return nil
+	case "get-base-image":
+		fmt.Print(getBaseImage(doc))
+		return nil
+	case "set-python-version":
+		v, err := value(args)
+		if err != nil {
+			return err
+		}
+		setPythonVersion(doc, v)
+	case "set-use-uv":
+		v, err := value(args)
+		if err != nil {
+			return err
+		}
+		setUseUv(doc, v == "true")
+	case "set-base-image":
+		v, err := value(args)
+		if err != nil {
+			return err
+		}
+		setBaseImage(doc, v)
+	default:
+		return fmt.Errorf("unknown command: %s", cmd)
+	}
+
+	out, err := dump(doc)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, out, 0o644)
+}
+
+func value(args []string) (string, error) {
+	if len(args) < 3 {
+		return "", fmt.Errorf("%s requires a value", args[0])
+	}
+	return args[2], nil
+}
+
+func boolStr(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}

helpers/pyproject/main_test.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func writeTemp(t *testing.T, contents string) string {
+	t.Helper()
+	dir := t.TempDir()
+	p := filepath.Join(dir, "pyproject.toml")
+	if err := os.WriteFile(p, []byte(contents), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+func TestRunSetThenGet(t *testing.T) {
+	p := writeTemp(t, sample)
+
+	if err := run([]string{"set-python-version", p, "3.13"}); err != nil {
+		t.Fatalf("set: %v", err)
+	}
+	data, err := os.ReadFile(p)
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if !strings.Contains(string(data), ">=3.13") {
+		t.Errorf("file not edited:\n%s", data)
+	}
+}
+
+func TestRunGetDoesNotWrite(t *testing.T) {
+	p := writeTemp(t, sample)
+	before, err := os.ReadFile(p)
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if err := run([]string{"get-python-version", p}); err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	after, err := os.ReadFile(p)
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if string(before) != string(after) {
+		t.Errorf("get-* must not modify the file:\nbefore:\n%s\nafter:\n%s", before, after)
+	}
+}
+
+func TestRunUnknownCommand(t *testing.T) {
+	p := writeTemp(t, sample)
+	if err := run([]string{"bogus", p}); err == nil {
+		t.Error("expected error for unknown command")
+	}
+}
+
+func TestRunRequiresValue(t *testing.T) {
+	p := writeTemp(t, sample)
+	if err := run([]string{"set-python-version", p}); err == nil {
+		t.Error("expected error when value is missing")
+	}
+}