feat(agent/agentcontainers): add feature options as envs (#18576)

agent/agentcontainers/devcontainercli.go

@@ -6,7 +6,10 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
+	"slices"
+	"strings"
 
 	"golang.org/x/xerrors"
 
@@ -26,12 +29,55 @@ type DevcontainerConfig struct {
 
 type DevcontainerMergedConfiguration struct {
 	Customizations DevcontainerMergedCustomizations `json:"customizations,omitempty"`
+	Features       DevcontainerFeatures             `json:"features,omitempty"`
 }
 
 type DevcontainerMergedCustomizations struct {
 	Coder []CoderCustomization `json:"coder,omitempty"`
 }
 
+type DevcontainerFeatures map[string]any
+
+// OptionsAsEnvs converts the DevcontainerFeatures into a list of
+// environment variables that can be used to set feature options.
+// The format is FEATURE_<FEATURE_NAME>_OPTION_<OPTION_NAME>=<value>.
+// For example, if the feature is:
+//
+//		"ghcr.io/coder/devcontainer-features/code-server:1": {
+//	   "port": 9090,
+//	 }
+//
+// It will produce:
+//
+//	FEATURE_CODE_SERVER_OPTION_PORT=9090
+//
+// Note that the feature name is derived from the last part of the key,
+// so "ghcr.io/coder/devcontainer-features/code-server:1" becomes
+// "CODE_SERVER". The version part (e.g. ":1") is removed, and dashes in
+// the feature and option names are replaced with underscores.
+func (f DevcontainerFeatures) OptionsAsEnvs() []string {
+	var env []string
+	for k, v := range f {
+		vv, ok := v.(map[string]any)
+		if !ok {
+			continue
+		}
+		// Take the last part of the key as the feature name/path.
+		k = k[strings.LastIndex(k, "/")+1:]
+		// Remove ":" and anything following it.
+		if idx := strings.Index(k, ":"); idx != -1 {
+			k = k[:idx]
+		}
+		k = strings.ReplaceAll(k, "-", "_")
+		for k2, v2 := range vv {
+			k2 = strings.ReplaceAll(k2, "-", "_")
+			env = append(env, fmt.Sprintf("FEATURE_%s_OPTION_%s=%s", strings.ToUpper(k), strings.ToUpper(k2), fmt.Sprintf("%v", v2)))
+		}
+	}
+	slices.Sort(env)
+	return env
+}
+
 type DevcontainerConfiguration struct {
 	Customizations DevcontainerCustomizations `json:"customizations,omitempty"`
 }