karatelabs/karate · error · RuntimeException

waitForHttp() needs a URL argument

Error message

waitForHttp() needs a URL argument

What it means

karate.waitForHttp(url) requires a URL as its first argument; calling it with zero arguments throws this RuntimeException immediately. It is a strict arity check protecting against a missing parameter.

Solutions

1. Pass the URL string as the first argument: karate.waitForHttp('http://localhost:8080/health')
2. Optionally pass a second Map argument for timeoutMs/pollMs configuration
3. Define the URL variable before the call

Example fix

// before
karate.waitForHttp();
// after
karate.waitForHttp('http://localhost:8080/health', { timeoutMs: 60000 });

// JS
if (!url) throw new Error('waitForHttp requires a url');
karate.waitForHttp(url);

// JS
function hasUrl(u) { return typeof u === 'string' && u.length > 0; }

if (arguments.length === 0) throw new Error('call waitForHttp(url) with a URL string');

When it happens

Trigger: Invoking karate.waitForHttp() with no arguments from a JS block or feature file.

Common situations: Refactoring a call and dropping the argument; confusing waitForHttp() with a no-arg variant; calling it before defining the URL variable.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• waitForPort() needs host and port arguments
• eval() needs one argument
• expect() needs at least one argument
• remove() needs two arguments: variable name and path
• setXml() needs at least two arguments: name and xml

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/9ec7392d4554b97a. Report an issue: GitHub.

Appendix: source

Thrown at karate-core/src/main/java/io/karatelabs/core/KarateJsUtils.java:1058

                }
                logger.info("*** exited socket wait successfully");
                return true;
            } catch (Exception e) {
                throw new RuntimeException("stop() failed: " + e.getMessage(), e);
            }
        };
    }

    // ========== Wait Utilities ==========

    /**
     * karate.waitForHttp(url) - Wait for an HTTP endpoint to become available.
     * Polls until a successful response (2xx or 3xx) is received.
     */
    static JavaInvokable waitForHttp() {
        return args -> {
            if (args.length == 0) {
                throw new RuntimeException("waitForHttp() needs a URL argument");
            }
            String url = args[0] + "";
            int timeoutMs = 30000;
            int pollMs = 250;
            if (args.length > 1 && args[1] instanceof Map) {
                @SuppressWarnings("unchecked")
                Map<String, Object> options = (Map<String, Object>) args[1];
                if (options.containsKey("timeout")) {
                    timeoutMs = ((Number) options.get("timeout")).intValue();
                }
                if (options.containsKey("interval")) {
                    pollMs = ((Number) options.get("interval")).intValue();
                }
            }
            long deadline = System.currentTimeMillis() + timeoutMs;
            java.net.http.HttpClient httpClient = java.net.http.HttpClient.newBuilder()
                    .connectTimeout(Duration.ofMillis(pollMs))
                    .build();

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