[planners] Add Python Poetry detection (#48)

## Summary

* Implements Python detection for Poetry projects #35
* Add new --debug flag
* Ensure we add stack to docker CMD errors
* Fix path being relative (previously `devbox build some/path` did not work)
* Adds example poetry project
* Use pex to create python executable.
* Specify new prod image that has python.

RFC:
* Add image to state. Currently only implemented for StartStage. Not exported to devbox.json

## How was it tested?

`devbox init examples/python-poetry`

`devbox shell examples/python-poetry`

<img width="741" alt="image" src="https://user-images.githubusercontent.com/544948/187796457-fe292d2e-5870-43f1-9363-f228ab843ecb.png">

`devbox build examples/python-poetry`

`docker run -p 8080:8080 devbox`

<img width="682" alt="image" src="https://user-images.githubusercontent.com/544948/187795681-6d3cf780-d6ba-4b27-be05-25369a7458e0.png">

Author: mikeland73

.gitignore

@@ -0,0 +1,24 @@
+# Global gitignore for the entire monorepo. Only add things here that truly
+# need to always be ignored regardless of project.
+#
+# If something is more specific to a particular project, add a gitignore in the
+# corresponding subdirectory.
+
+# MacOS filesystem
+.DS_Store
+
+# Editors
+.idea
+.vscode
+
+# NodeJS
+node_modules
+.yalc
+dist
+
+
+# Python
+*.pyc
+__pycache__/
+*.py[cod]
+*$py.class

README.md

@@ -140,6 +140,7 @@ Devbox makes it easy to package your application into an OCI-compliant container
 Devbox currently detects the following languages:
 
 - Go
+- Python (Poetry)
 
 Want more languages? [Ask for a new Language](https://github.com/jetpack-io/devbox/issues) or contribute one via a Pull Request.
 

boxcli/args.go

@@ -3,13 +3,23 @@
 
 package boxcli
 
+import (
+	"path/filepath"
+
+	"github.com/pkg/errors"
+)
+
 // Functions that help parse arguments
 
 // If args empty, defaults to the current directory
 // Otherwise grabs the path from the first argument
 func pathArg(args []string) string {
 	if len(args) > 0 {
-		return args[0]
+		p, err := filepath.Abs(args[0])
+		if err != nil {
+			panic(errors.WithStack(err)) // What even triggers this?
+		}
+		return p
 	}
 	return "."
 }

boxcli/midcobra/debug.go

@@ -0,0 +1,43 @@
+// Copyright 2022 Jetpack Technologies Inc and contributors. All rights reserved.
+// Use of this source code is governed by the license in the LICENSE file.
+
+package midcobra
+
+import (
+	"log"
+	"os"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+)
+
+type DebugMiddleware struct {
+	flag *pflag.Flag
+}
+
+var _ Middleware = (*DebugMiddleware)(nil)
+
+func (d *DebugMiddleware) AttachToFlag(flags *pflag.FlagSet, flagName string) {
+	flags.Bool(
+		flagName,
+		false,
+		"Show full stack traces on errors",
+	)
+	d.flag = flags.Lookup(flagName)
+	d.flag.Hidden = true
+}
+
+func (d *DebugMiddleware) preRun(cmd *cobra.Command, args []string) {}
+
+func (d *DebugMiddleware) postRun(cmd *cobra.Command, args []string, runErr error) {
+	if runErr != nil && d.Debug() {
+		log.Printf("Error: %+v\n", runErr)
+	}
+}
+
+func (d *DebugMiddleware) Debug() bool {
+	if d != nil && d.flag.Changed {
+		return d.flag.Value.String() == "true"
+	}
+	return os.Getenv("DEBUG") != ""
+}

boxcli/root.go

@@ -6,6 +6,7 @@ package boxcli
 import (
 	"context"
 	"errors"
+	"fmt"
 	"os"
 	"os/exec"
 
@@ -14,6 +15,8 @@ import (
 	"go.jetpack.io/devbox/build"
 )
 
+var debugMiddleware *midcobra.DebugMiddleware = &midcobra.DebugMiddleware{}
+
 func RootCmd() *cobra.Command {
 	command := &cobra.Command{
 		Use:   "devbox",
@@ -41,16 +44,29 @@ func RootCmd() *cobra.Command {
 	command.AddCommand(RemoveCmd())
 	command.AddCommand(ShellCmd())
 	command.AddCommand(VersionCmd())
+
+	debugMiddleware.AttachToFlag(command.PersistentFlags(), "debug")
+
 	return command
 }
 
 func Execute(ctx context.Context, args []string) int {
+	defer func() {
+		if r := recover(); r != nil {
+			if debugMiddleware.Debug() {
+				fmt.Printf("PANIC (DEBUG MODE ON): %+v\n", r)
+			} else {
+				fmt.Printf("Error: %s\n", r)
+			}
+		}
+	}()
 	exe := midcobra.New(RootCmd())
 	exe.AddMiddleware(midcobra.Telemetry(&midcobra.TelemetryOpts{
 		AppName:      "devbox",
 		AppVersion:   build.Version,
 		TelemetryKey: build.TelemetryKey,
 	}))
+	exe.AddMiddleware(debugMiddleware)
 	return exe.Execute(ctx, args)
 }
 

docker/docker.go

@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 
 	"github.com/imdario/mergo"
+	"github.com/pkg/errors"
 	"golang.org/x/exp/slices"
 )
 
@@ -59,7 +60,7 @@ func Build(path string, opts ...BuildOptions) error {
 		return err
 	}
 
-	args := []string{"build", "."}
+	args := []string{"build", path}
 	args = ToArgs(args, flags)
 
 	dir, fileName := parsePath(path)
@@ -78,7 +79,7 @@ func Build(path string, opts ...BuildOptions) error {
 	cmd.Stderr = os.Stderr
 	cmd.Env = append(os.Environ(), "BUILDKIT=1")
 	cmd.Dir = dir
-	return cmd.Run()
+	return errors.WithStack(cmd.Run())
 }
 
 func parsePath(path string) (string, string) {