apache/shenyu · error · ShenyuWasmInitException

memory not available in wasm file

Error message

memory not available in wasm file: ${wasmName}

What it means

After instantiating the WebAssembly module with Chicory, WasmLoader requires the module to export a linear memory. When instance.memory() returns null — the compiled .wasm has no exported memory — it throws ShenyuWasmInitException because the gateway cannot read/write the module's data without it.

Solutions

1. Recompile the wasm source so linear memory is exported (e.g. in C with clang: -Wl,--export-memory; in wat: (export "memory" (memory 0))).
2. Verify the module's exports with wasm-objdump -x module.wasm or wasm-tools and confirm a memory export exists.
3. Use a wasm binary produced by the ShenYu plugin toolchain/template, which guarantees an exported memory.
4. If you cannot change the binary, wrap it in a module that re-exports memory or switch to a runtime path that does not require host-side memory access.

Example fix

// wat before
(module (memory (export "mem") 1))
// after
(module (memory 1) (export "memory" (memory 0)))

// Build-time / pre-load check with wasm tooling
// wasm-objdump -x module.wasm | grep -q 'memory' || echo 'ERROR: no memory export'

try {
    WasmLoader loader = new MyWasmPlugin();
} catch (ShenyuWasmInitException e) {
    if (e.getMessage().startsWith("memory not available")) { /* rebuild wasm with exported memory */ }
    throw e;
}

When it happens

Trigger: Loading a .wasm module whose exports lack 'memory' (e.g. built without exported memory or with memory not exported in the wasm binary), during WasmLoader construction.

Common situations: Compiling C/Rust/AssemblyScript to wasm with memory kept internal or memory64/exotic memory settings; using a wasm binary built for a different runtime that does not export memory; hand-written wat files missing an (export "memory" ...) clause.

Related errors

• Can't find wasm file
• no more memory can be used !
• The task queue does not have executor!
• WASI proc_exit( ) from
• dynamic build JsonMarshaller descriptor is fail

AI-assisted analysis of apache/shenyu@567142e072 (2026-09-12). Data as JSON: /api/errors/6026ac0bfb9e04bf. Report an issue: GitHub.

Appendix: source

Thrown at shenyu-plugin/shenyu-plugin-wasm-api/src/main/java/org/apache/shenyu/plugin/wasm/api/loader/WasmLoader.java:150

                this.instance = Instance.builder(module)
                         .withImportValues(store.toImportValues())
                         .withStart(false)
                         .build();
            }

            // Call _initialize if present (required by TinyGo -target wasm-unknown).
            try {
                ExportFunction initFn = instance.export("_initialize");
                if (Objects.nonNull(initFn)) {
                    initFn.apply();
                    LOG.debug("Called _initialize for {}", wasmName);
                }
            } catch (com.dylibso.chicory.wasm.InvalidException e) {
                LOG.debug("No _initialize export in {}", wasmName);
            }

            if (Objects.isNull(instance.memory())) {
                throw new ShenyuWasmInitException("memory not available in wasm file: " + wasmName);
            }
        } catch (IOException e) {
            throw new ShenyuWasmInitException(e);
        }
    }

    private void registerWasiStubs(final Store store) {
        // Use Chicory's built-in full WASI preview1 implementation for comprehensive
        // WASI function coverage, matching the previous wasmtime-java behavior.
        // Only inherit stdout/stderr so WASM guest output (e.g. Go println,
        // Rust eprintln!) is visible for debugging. Avoid inheriting the full
        // system context (env/args/filesystem) for security hardening.
        var options = com.dylibso.chicory.wasi.WasiOptions.builder()
                .withStdout(System.out)
                .withStderr(System.err)
                .build();
        var wasi = com.dylibso.chicory.wasi.WasiPreview1.builder()
                .withOptions(options)

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