v0.6.0

🎉 Milestone 6 Release: Ballerina Nutcracker

This milestone adds server-side HTTP, seven new standard library modules, a bal build command, and language subset 9.

🌐 HTTP service support

The headline feature: ballerina/http can now serve traffic, not just call it.

• http:Listener with declarative attachment or programmatic attach / detach
• Resource functions for all methods, with typed path parameters ([int], [string], [boolean], [decimal]) and rest paths
• ListenerConfiguration — host, timeout, httpVersion (HTTP/2 by default, serving both HTTP/1.1 and HTTP/2), secureSocket
• TLS and mutual TLS; graceful stop that drains in-flight requests
• Automatic 404 for unmatched paths, 405 for the wrong method

import ballerina/http;

service /api on new http:Listener(9090) {

    resource function get greeting/[string name]() returns http:Response {
        http:Response resp = new;
        resp.setTextPayload(string `Hello, ${name}!`);
        return resp;
    }

    resource function post item() returns http:Response {
        http:Response resp = new;
        resp.statusCode = 201;
        resp.setJsonPayload({status: "created"});
        return resp;
    }
}

Not in this cut: resource functions return http:Response, error, or () — bare string/anydata returns and status-code response types are not yet supported, and there is no http:Caller, parameter binding, or @http:ServiceConfig style configuration.

On the client side: compression negotiation, proxy support, responseLimits, poolConfig, the forward action, a Request class and Method enum, plus payload setters, header mutators, and query-parameter accessors.

🚀 Language features (subset 9)

Annotations — declarations and attachments (marker, repeated, source-only), values from constant and runtime expressions, and annotation access:

type Info readonly & record {| string label; |};

annotation Info runtimeInfo on type;

@runtimeInfo {label: "person"}
type Person record {| string name; |};

Info? value = Person.@runtimeInfo;

Template expressions — string templates are new, and XML templates gained interpolation in content and attributes:

string name = "world";
io:println(string `Hello, ${name}!`);                 // Hello, world!
io:println(xml `<greeting>Hello, ${name}!</greeting>`);

Concurrency — the lock statement and isolated module-level variables:

isolated int counter = 0;

isolated function bump() returns int {
    lock {
        counter += 1;
        return counter;
    }
}

Query expressions — the group by and collect clauses:

var grouped = from var x in xs group by x select [x];
int[] all = from var x in xs collect x;

Also in subset 9:

• Services & objects — module listener and service declarations, resource methods and resource access actions (f->/path/["a"]/[1]()), service/readonly/distinct class qualifiers, object type inclusion
• Types — distinct error and object types, typedesc support, stream values backed by user-defined iterators
• Expressions — spread members in list constructors, foreach over XML, XML equality
• Language libraries — new lang.float (full math surface), lang.decimal, lang.boolean, lang.object; base64/base16 on lang.array; toBytes/fromBytes on lang.string; cloneWithType and fromJsonWithType on lang.value

📚 Standard library

Seven new modules, plus file I/O for ballerina/io:

Module	What it covers
crypto	Hashing, HMAC, password hashing (BCrypt, Argon2, PBKDF2), AES, RSA and ECDSA, key loading
io	Whole-file read/write for strings, lines, bytes, JSON, and XML
log	printDebug / printInfo / printWarn / printError with structured key-value pairs
math.vector	Norms, dot product, cosine similarity, Euclidean and Manhattan distance
os	Environment variables, user info, subprocess execution
random	Cryptographically secure random values
time	UTC and civil time, IANA time zones, RFC 3339 / RFC 5322, duration arithmetic
url	Percent-encoding and decoding across several charsets

import ballerina/crypto;
import ballerina/io;
import ballerina/log;
import ballerina/time;

public function main() returns error? {
    time:Utc now = time:utcNow();
    check io:fileWriteJson("stamp.json", {at: time:utcToString(now)});
    json content = check io:fileReadJson("stamp.json");
    io:println(content);

    byte[] digest = crypto:hashSha256("hello".toBytes());
    log:printInfo("digest computed", length = digest.length());
}

🛠️ CLI & tooling

Two new commands round out the CLI:

Command	Description
bal pack [<package-dir>]	Build the .bala distribution archive of a package
bal build [<package-dir>]	Build a standalone executable that bundles the Ballerina runtime

bal build produces a self-contained binary at target/bin/<package-name> (override with -o), and cross-compiles to any supported platform with --target-os / --target-arch:

bal build hello
bal build hello --target-os linux --target-arch arm64

Release binaries are published for linux/amd64, linux/arm64, darwin/amd64, darwin/arm64, and windows/amd64.

📦 Projects & packages

• Standard libraries and language libraries now ship as bundled .bala packages
• Depend on packages from a local repository, or route resolution through a custom repository
• Resolve external packages that carry native code

🔍 New diagnostics

The compiler now reports unused local variables, unused import prefixes, returns never functions that can complete normally, and invalid service declarations.

🔗 Resources

• Release: v0.6.0
• Supported features: Language: subset9 · Standard Library: subset2
• Examples: Language: subset9 · Standard Library: subset2
• Full Changelog: v0.5.0...v0.6.0