feat: make Supervisor logfile path configurable via environment variable

Added SUPERVISOR_LOGFILE environment variable to configure the path to
the Supervisor main logfile for reading via XML-RPC.

Changes:
- Added SUPERVISOR_LOGFILE to .env.example with default path
- Removed getLogfilePath() method and cachedLogfilePath field from SupervisorClient
- Updated readLog() to use environment variable with fallback chain:
  1. Explicitly provided logfilePath parameter
  2. SUPERVISOR_LOGFILE environment variable
  3. Default: /var/log/supervisor/supervisord.log
- Added debug logging to readLog() for troubleshooting

This allows users to configure the correct logfile path for their
Supervisor installation when using the custom 3-parameter XML-RPC
readLog implementation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.env.example

@@ -11,6 +11,10 @@ SUPERVISOR_PORT=9001
 # SUPERVISOR_USERNAME=user
 # SUPERVISOR_PASSWORD=pass
 
+# Optional: Path to supervisord main logfile (for reading via XML-RPC)
+# Default: /var/log/supervisor/supervisord.log
+# SUPERVISOR_LOGFILE=/var/log/supervisor/supervisord.log
+
 # Logging Configuration
 # Log level: debug, info, warn, error (default: info in prod, debug in dev)
 LOG_LEVEL=info

lib/supervisor/client.ts

@@ -25,7 +25,6 @@ export class SupervisorClient {
   private client: xmlrpc.Client;
   private config: SupervisorClientConfig;
   private logger: ReturnType<typeof createLogger>;
-  private cachedLogfilePath?: string;
 
   constructor(config: SupervisorClientConfig) {
     this.config = config;
@@ -102,40 +101,6 @@ export class SupervisorClient {
     return this.call<string>('supervisor.getSupervisorVersion');
   }
 
-  /**
-   * Get logfile path from API version metadata
-   * Caches the result after first call
-   */
-  private async getLogfilePath(): Promise<string> {
-    if (this.cachedLogfilePath) {
-      return this.cachedLogfilePath;
-    }
-
-    // Get API version which should contain logfile path in metadata
-    const apiVersionData = await this.call<any>('supervisor.getAPIVersion');
-
-    // Parse the response to extract logfile path
-    // The exact structure depends on your supervisor API implementation
-    // Common formats might be:
-    // - { version: "3.0", logfile: "/path/to/log" }
-    // - Just a string with embedded metadata
-    let logfilePath: string;
-
-    if (typeof apiVersionData === 'object' && apiVersionData.logfile) {
-      logfilePath = apiVersionData.logfile;
-    } else if (typeof apiVersionData === 'object' && apiVersionData.logfile_path) {
-      logfilePath = apiVersionData.logfile_path;
-    } else {
-      // Fallback to default supervisord log location if not found in metadata
-      this.logger.warn('Could not extract logfile path from getAPIVersion, using default');
-      logfilePath = '/var/log/supervisor/supervisord.log';
-    }
-
-    this.cachedLogfilePath = logfilePath;
-    this.logger.debug({ logfilePath }, 'Retrieved and cached logfile path');
-    return logfilePath;
-  }
-
   async getIdentification(): Promise<string> {
     return this.call<string>('supervisor.getIdentification');
   }
@@ -288,8 +253,9 @@ export class SupervisorClient {
   }
 
   async readLog(offset: number, length: number, logfilePath?: string): Promise<string> {
-    // If logfilePath not provided, get it from API version metadata
-    const path = logfilePath || await this.getLogfilePath();
+    // Use provided path, or fall back to env variable, or use default
+    const path = logfilePath || process.env.SUPERVISOR_LOGFILE || '/var/log/supervisor/supervisord.log';
+    this.logger.debug({ path, offset, length }, 'Reading supervisor main log');
     return this.call<string>('supervisor.readLog', [offset, length, path]);
   }