Merge pull request #11 from UnitVectorY-Labs/env

Add support for environment variables passed to token command

Author: JaredHatfield

README.md

@@ -27,6 +27,8 @@ The following attributes can be specified in the file:
 - `version`: The version of the MCP server
 - `url`: The URL of the GraphQL endpoint
 - `token_command`: The command to use to request the Bearer token for the `Authorization` header (optional)
+- `env`: A map of environment variables to pass to the token command (optional)
+- `env_passthrough`: If set to `true`, passes all environment variables used when invoking mcp-graphql-forge to the token command; if used in conjunction with `env`, the variables from `env` will take precedence (optional, defaults to `false`)
 
 An example configuration would look like:
 

example/forge.yaml

@@ -2,4 +2,11 @@
 name: "ExampleServer"
 version: "0.1.0"
 url: "https://api.github.com/graphql"
-token_command: "gh auth token"
+token_command: "gh auth token"
+
+# All of the environment variables passed to mcp-graphql-forge will be passed when invoking the token command.
+# env_passthrough: true
+
+# Specific environment variables to pass when invoking the token command.
+env:
+  FOO: "BAR"

main.go

@@ -15,6 +15,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"strings"
 
 	"gopkg.in/yaml.v3"
 
@@ -24,10 +25,12 @@ import (
 
 // ForgeConfig holds global server settings
 type ForgeConfig struct {
-	Name         string `yaml:"name"`
-	Version      string `yaml:"version"`
-	URL          string `yaml:"url"`
-	TokenCommand string `yaml:"token_command"`
+	Name           string            `yaml:"name"`
+	Version        string            `yaml:"version"`
+	URL            string            `yaml:"url"`
+	TokenCommand   string            `yaml:"token_command"`
+	Env            map[string]string `yaml:"env,omitempty"`
+	EnvPassthrough bool              `yaml:"env_passthrough,omitempty"`
 }
 
 // ToolConfig holds one tool's YAML definition
@@ -142,6 +145,36 @@ func makeHandler(cfg ForgeConfig, tcfg ToolConfig) server.ToolHandlerFunc {
 				cmd = exec.Command("sh", "-c", cfg.TokenCommand)
 			}
 
+			// Build merged environment: start with os.Environ() if passthrough, else start empty,
+			// then overlay values from cfg.Env to ensure overrides.
+			var envList []string
+			if cfg.EnvPassthrough {
+				envList = os.Environ()
+			} else {
+				envList = []string{}
+			}
+
+			for key, value := range cfg.Env {
+				// Remove any existing entries for this key
+				prefix := key + "="
+				filtered := envList[:0]
+				for _, e := range envList {
+					if !strings.HasPrefix(e, prefix) {
+						filtered = append(filtered, e)
+					}
+				}
+				envList = append(filtered, fmt.Sprintf("%s=%s", key, value))
+			}
+
+			cmd.Env = envList
+
+			if isDebug {
+				log.Printf("Executing token command: %s", cfg.TokenCommand)
+				if len(cmd.Env) > 0 {
+					log.Printf("Environment variables: %v", cmd.Env)
+				}
+			}
+
 			// Only get a token if the command is specified
 			out, err := cmd.Output()
 			if err != nil {