What causes "Failed to open stream for: {path}" in karatelabs/karate?

Print the resolved path in the message and confirm it exists and is a regular file (Files.isRegularFile)

karatelabs/karate · error · RuntimeException

Failed to open stream for

Error message

Failed to open stream for: {path}

What it means

PathResource.getStream() opens the underlying file with Files.newInputStream() and wraps any failure (file deleted between existence check and open, permission denied, is a directory, I/O error) in this RuntimeException with the resource path in the message. Callers receive a stream-backed view of the resource, so a failing open breaks any downstream read.

Solutions

Print the resolved path in the message and confirm it exists and is a regular file (Files.isRegularFile)
Check read permissions on the file and its parent directories for the process user
Re-create the resource from a fresh, verified path rather than a cached one
If the file is generated by an earlier step, add synchronization/wait so it exists before opening

Example fix

// before
Resource r = Resource.path("missing-report.html");
InputStream is = r.getStream(); // throws if deleted
// after
Resource r = Resource.path("report.html");
if (Files.isRegularFile(Paths.get("report.html"))) {
    InputStream is = r.getStream();
}

Defensive patterns

Strategy: validation

Validate before calling

// Java: verify the file is openable before getting the stream
Path p = Paths.get("report.html");
if (!Files.isRegularFile(p) || !Files.isReadable(p)) {
    throw new IllegalStateException("not a readable file: " + p);
}

Try / catch

try {
    InputStream is = pathResource.getStream();
} catch (RuntimeException e) {
    if (e.getMessage().startsWith("Failed to open stream for:")) {
        logger.error("open failed for {} cause: {}", e.getMessage(), e.getCause());
    }
}

Prevention

Create PathResource from freshly verified paths; avoid caching across steps that clean temp dirs
Check read permissions and that the path is not a directory
Use classpath resources to avoid working-directory drift between environments

When it happens

Trigger: The file was removed or renamed after the PathResource was created; process lacks read permission on the file or a parent directory; the path points to a directory; the file is on an unmounted/network volume that became unavailable; file is locked by another process with incompatible sharing (Windows).

Common situations: Temp files cleaned up mid-run by another process; reading files created by a previous test step that ran in a different working directory; permission differences between local dev and CI user; antivirus/file-lock contention on Windows.

Understand the failure class

Background: "open() failed", "failed to open file", "cannot create file" — what a file open error means and how to fix it — this error's family across 42 libraries.

Related errors

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/1a71691411e554c1. Report an issue: GitHub.

Appendix: source

Thrown at karate-js/src/main/java/io/karatelabs/common/PathResource.java:209

            boolean hasExtension = pathStr.matches(".*\\.[a-zA-Z0-9]+$");
            base = hasExtension ? path.getParent() : path;
        }
        Path resolved = base.resolve(childPath);
        return new PathResource(resolved, root, classpath, classpathRoot);
    }

    @Override
    public Resource getParent() {
        Path parentPath = path.getParent();
        return parentPath != null ? new PathResource(parentPath, root, classpath, classpathRoot) : null;
    }

    @Override
    public InputStream getStream() {
        try {
            return Files.newInputStream(path);
        } catch (Exception e) {
            throw new RuntimeException("Failed to open stream for: " + path, e);
        }
    }

    @Override
    public String getRelativePath() {
        return relativePath;
    }

    @Override
    public String getText() {
        if (text == null) {
            try {
                bytes = Files.readAllBytes(path);
                text = FileUtils.toString(bytes);
            } catch (Exception e) {
                throw new RuntimeException("Failed to read text from: " + path, e);
            }
        }

View on GitHub (pinned to a22eb90246)