Clean up GEOIPUPDATE_PROXY_USER_PASSWORD_FILE support

CHANGELOG.md

@@ -37,6 +37,10 @@
 - The Docker images now carry `org.opencontainers.image.*` labels.
 - A prerelease no longer moves the `latest`, `v8` and `v8.1` Docker tags, or the
   release marked "Latest" on GitHub.
+- Added the `GEOIPUPDATE_PROXY_USER_PASSWORD_FILE` environment variable. It sets
+  the proxy user name and password from a file, in the same way as
+  `GEOIPUPDATE_ACCOUNT_ID_FILE` and `GEOIPUPDATE_LICENSE_KEY_FILE`. Pull request
+  by Tom Hubrecht. GitHub #570.
 
 ## 8.0.0 (2026-07-10)
 

doc/GeoIP.conf.md

@@ -13,19 +13,29 @@ The file consists of one setting per line. Lines starting with `#`
 are comments and will not be processed. All setting keywords are case
 sensitive.
 
+The `AccountID`, `LicenseKey` and `ProxyUserPassword` settings can also be
+overridden at run time by an environment variable that contains the path to a
+file, for example `GEOIPUPDATE_LICENSE_KEY_FILE`. The file holds the value.
+`geoipupdate` removes leading and trailing white space from the contents of
+the file. If the file is empty or contains only white space, `geoipupdate`
+returns an error.
+
 ## Required settings:
 
 `AccountID`
 
 :   Your MaxMind account ID. This was formerly known as `UserId`. This can be
     overridden at run time by either the `GEOIPUPDATE_ACCOUNT_ID` or the
-    `GEOIPUPDATE_ACCOUNT_ID_FILE` environment variables.
+    `GEOIPUPDATE_ACCOUNT_ID_FILE` environment variables. If
+    `GEOIPUPDATE_ACCOUNT_ID_FILE` is set and not empty, `geoipupdate` uses the
+    file and ignores `GEOIPUPDATE_ACCOUNT_ID`.
 
 `LicenseKey`
 
 :   Your case-sensitive MaxMind license key. This can be overridden at run time
     by either the `GEOIPUPDATE_LICENSE_KEY` or `GEOIPUPDATE_LICENSE_KEY_FILE`
-    environment variables.
+    environment variables. If `GEOIPUPDATE_LICENSE_KEY_FILE` is set and not
+    empty, `geoipupdate` uses the file and ignores `GEOIPUPDATE_LICENSE_KEY`.
 
 `EditionIDs`
 
@@ -59,8 +69,11 @@ sensitive.
 `ProxyUserPassword`
 
 :   The proxy user name and password, separated by a colon. For instance,
-    `username:password`. This can be overridden at run time by the
-    `GEOIPUPDATE_PROXY_USER_PASSWORD` environment variable.
+    `username:password`. This can be overridden at run time by either the
+    `GEOIPUPDATE_PROXY_USER_PASSWORD` or the
+    `GEOIPUPDATE_PROXY_USER_PASSWORD_FILE` environment variables. If
+    `GEOIPUPDATE_PROXY_USER_PASSWORD_FILE` is set and not empty, `geoipupdate`
+    uses the file and ignores `GEOIPUPDATE_PROXY_USER_PASSWORD`.
 
 `PreserveFileTimes`
 

doc/docker.md

@@ -38,6 +38,8 @@ The following environment variables are optional:
   1080 will be used.
 * `GEOIPUPDATE_PROXY_USER_PASSWORD` - The proxy user name and password,
   separated by a colon. For instance, `username:password`.
+* `GEOIPUPDATE_PROXY_USER_PASSWORD_FILE` - A file containing the proxy user
+  name and password, separated by a colon.
 * `GEOIPUPDATE_PRESERVE_FILE_TIMES` - Whether to preserve modification times
   of files downloaded from the server. This option is either `0` or `1`. The
   default is `0`.
@@ -52,6 +54,14 @@ individually with the `-e` flag.
 
 Environment variables override any options set in the config file.
 
+`GEOIPUPDATE_ACCOUNT_ID`, `GEOIPUPDATE_LICENSE_KEY` and
+`GEOIPUPDATE_PROXY_USER_PASSWORD` each have a `_FILE` form, for example
+`GEOIPUPDATE_LICENSE_KEY_FILE`. If the `_FILE` form is set and not empty,
+`geoipupdate` uses the value from the file and ignores the other variable.
+`geoipupdate` removes leading and trailing white space from the contents of the
+file. If the file is empty or contains only white space, `geoipupdate` returns
+an error.
+
 ## Running
 
 ### docker run

internal/geoipupdate/config.go

@@ -287,39 +287,14 @@ func setConfigFromFile(config *Config, path string) error {
 	return nil
 }
 
-// getValueFromEnvFile returns the value associated to an env variable or from a file containing it.
-func getValueFromEnvFile(key string) (string, bool, error) {
-	var res string
-	var found bool
-
-	if value, ok := os.LookupEnv(key); ok {
-		res = value
-		found = true
-	}
-
-	if value := os.Getenv(key + "_FILE"); value != "" {
-		var err error
-
-		content, err := os.ReadFile(filepath.Clean(value))
-		if err != nil {
-			return "", true, fmt.Errorf("failed to open %s_FILE: %w", key, err)
-		}
-
-		found = true
-		res = strings.TrimSpace(string(content))
-	}
-
-	return res, found, nil
-}
-
 // setConfigFromEnv sets Config fields based on environment variables.
 func setConfigFromEnv(config *Config) error {
-	if value, found, err := getValueFromEnvFile("GEOIPUPDATE_ACCOUNT_ID"); found {
-		if err != nil {
-			return err
-		}
-
-		config.AccountID, err = strconv.Atoi(value)
+	accountID, found, err := lookupFileOrEnv("GEOIPUPDATE_ACCOUNT_ID")
+	if err != nil {
+		return err
+	}
+	if found {
+		config.AccountID, err = strconv.Atoi(accountID)
 		if err != nil {
 			return errors.New("invalid account ID format")
 		}
@@ -344,12 +319,12 @@ func setConfigFromEnv(config *Config) error {
 		config.URL = u.String()
 	}
 
-	if value, found, err := getValueFromEnvFile("GEOIPUPDATE_LICENSE_KEY"); found {
-		if err != nil {
-			return err
-		}
-
-		config.LicenseKey = value
+	licenseKey, found, err := lookupFileOrEnv("GEOIPUPDATE_LICENSE_KEY")
+	if err != nil {
+		return err
+	}
+	if found {
+		config.LicenseKey = licenseKey
 	}
 
 	if value, ok := os.LookupEnv("GEOIPUPDATE_LOCK_FILE"); ok {
@@ -378,12 +353,12 @@ func setConfigFromEnv(config *Config) error {
 		config.proxyURL = value
 	}
 
-	if value, found, err := getValueFromEnvFile("GEOIPUPDATE_PROXY_USER_PASSWORD"); found {
-		if err != nil {
-			return err
-		}
-
-		config.proxyUserInfo = value
+	proxyUserInfo, found, err := lookupFileOrEnv("GEOIPUPDATE_PROXY_USER_PASSWORD")
+	if err != nil {
+		return err
+	}
+	if found {
+		config.proxyUserInfo = proxyUserInfo
 	}
 
 	if value, ok := os.LookupEnv("GEOIPUPDATE_RETRY_FOR"); ok {
@@ -404,6 +379,33 @@ func setConfigFromEnv(config *Config) error {
 	return nil
 }
 
+// lookupFileOrEnv returns the value of the environment variable named by key
+// and whether it is set, as os.LookupEnv does. If the variable named by
+// key+"_FILE" is not empty, lookupFileOrEnv instead reads the file at that
+// path. It then returns the file contents, with leading and trailing white
+// space removed, and true. If nothing remains, it returns an error. The file
+// takes precedence over the variable named by key.
+func lookupFileOrEnv(key string) (string, bool, error) {
+	if path := os.Getenv(key + "_FILE"); path != "" {
+		content, err := os.ReadFile(filepath.Clean(path))
+		if err != nil {
+			return "", false, fmt.Errorf("failed to read %s_FILE: %w", key, err)
+		}
+		value := strings.TrimSpace(string(content))
+		if value == "" {
+			return "", false, fmt.Errorf(
+				"%s_FILE is set to %q, but that file is empty or contains only white space",
+				key,
+				path,
+			)
+		}
+		return value, true, nil
+	}
+
+	value, found := os.LookupEnv(key)
+	return value, found, nil
+}
+
 // setConfigFromFlags sets Config fields based on option flags.
 func setConfigFromFlags(config *Config, flagOptions ...Option) error {
 	for _, option := range flagOptions {