Log file path is empty, no log file path configured in the…

Error message

Log file path is empty, no log file path configured in the current configuration file

What it means

LogBaseServlet.prepareLogResponse guards every log-file request: if the configured logPath is blank it returns HTTP 400 BAD_REQUEST and logs this warning, because no log directory is configured in the current configuration file, so any log name/path request cannot be served.

Solutions

Configure a file appender with an explicit fileName/directory in the node's log4j2 (or chosen logging) configuration and restart.
Set the log path system property/env (e.g., -Dseatunnel.logs.path=...) when launching the node.
Verify with a GET to the log-name endpoint that the path resolves (see errorIndex 3718).
Avoid blank config values; comment removals in logging config can silently blank the path.

Example fix

// before (log4j2.properties, console only, no file appender)
// rootLogger.appenderRef.stdout.ref = console
// after
// appender.file.type = File
// appender.file.name = file
// appender.file.fileName = ${sys:seatunnel.logs.path}/seatunnel.log
// rootLogger.appenderRef.file.ref = file

Defensive patterns

Strategy: validation

Validate before calling

// before calling log endpoints, verify config
// String logPath = System.getProperty("seatunnel.logs.path");
// if (logPath == null || logPath.isBlank()) {
//     throw new IllegalStateException("log path not configured");
// }
// if (!Files.isDirectory(Paths.get(logPath))) { throw ... }

Try / catch

try {
    Response r = restGet("/log/name");
    if (r.status() == 400) { configureLogPath(); }
} catch (Exception e) { handle(e); }

Prevention

Ensure log4j2 config always defines a file appender path
Set -Dseatunnel.logs.path at node startup
Test log endpoints after any logging config edits

When it happens

Trigger: Any GET to a log-content/log-download endpoint on a node whose logging configuration lacks a file path (blank logPath passed to prepareLogResponse), e.g., console-only logging setup or missing log4j2 file-appender configuration.

Common situations: Deployment using console appender only; log4j2.properties/custom config missing the file appender path; env var like SEATUNNEL_HOME unset so derived log path resolves empty; mis-edited config removing the file path.

Understand the failure class

Background: "missing required config value" errors: why libraries refuse to start when a configuration key is empty, unset, or blank — this error's family across 48 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/dd3481422cd09d39. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-engine/seatunnel-engine-server/src/main/java/org/apache/seatunnel/engine/server/rest/servlet/LogBaseServlet.java:53

    public LogBaseServlet(NodeEngineImpl nodeEngine) {
        super(nodeEngine);
    }

    /**
     * Prepares the servlet log response after enforcing the configured log directory boundary.
     *
     * <p>The requested log file is resolved to its canonical path before reading so that relative
     * segments and symbolic links cannot escape the canonical log directory.
     *
     * @param resp response used to return status and log content
     * @param logPath configured log directory
     * @param logName requested log file name from the request URI
     */
    protected void prepareLogResponse(HttpServletResponse resp, String logPath, String logName) {
        if (StringUtils.isBlank(logPath)) {
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            log.warn(
                    "Log file path is empty, no log file path configured in the current configuration file");
            return;
        }
        String logFilePath = new File(logPath, logName).getPath();
        try {
            String canonicalLogDir = new File(logPath).getCanonicalPath();
            String canonicalFilePath = new File(logFilePath).getCanonicalPath();
            if (!canonicalFilePath.startsWith(canonicalLogDir + File.separator)
                    && !canonicalFilePath.equals(canonicalLogDir)) {
                resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
                log.warn(
                        "Path traversal attempt blocked - Requested: {}, Resolved: {}, LogDir: {}",
                        logName,
                        canonicalFilePath,
                        canonicalLogDir);
                return;
            }
            String logContent = FileUtils.readFileToStr(new File(canonicalFilePath).toPath());

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