retoor
819bbd5091
Add three new example scripts demonstrating the fswatch, sysinfo, and udp modules with file watching, system metrics, and UDP echo server/client patterns. Reorder the manual API sidebar navigation to list modules alphabetically, removing deprecated entries like websocket, tls, net, json, regex, jinja, os, signal, subprocess, sqlite, and timer while adding argparse, dataset, fswatch, and html.
323 lines
14 KiB
HTML
323 lines
14 KiB
HTML
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<div class="version">v0.4.0</div>
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<span class="separator">/</span>
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<span>env</span>
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</nav>
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<article>
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<h1>env</h1>
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<p>The <code>env</code> module provides access to environment variables for reading, writing, and deleting values.</p>
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<pre><code>import "env" for Environment</code></pre>
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<h2>Environment Class</h2>
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<div class="class-header">
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<h3>Environment</h3>
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<p>Environment variable access</p>
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</div>
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<h3>Static Methods</h3>
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<div class="method-signature">
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<span class="method-name">Environment.get</span>(<span class="param">name</span>) → <span class="type">String|null</span>
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</div>
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<p>Gets the value of an environment variable.</p>
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<ul class="param-list">
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<li><span class="param-name">name</span> <span class="param-type">(String)</span> - Name of the environment variable</li>
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<li><span class="returns">Returns:</span> Value of the variable, or null if not set</li>
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</ul>
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<pre><code>var home = Environment.get("HOME")
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System.print(home) // /home/alice
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var missing = Environment.get("UNDEFINED_VAR")
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System.print(missing) // null</code></pre>
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<div class="method-signature">
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<span class="method-name">Environment.set</span>(<span class="param">name</span>, <span class="param">value</span>)
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</div>
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<p>Sets an environment variable.</p>
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<ul class="param-list">
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<li><span class="param-name">name</span> <span class="param-type">(String)</span> - Name of the environment variable</li>
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<li><span class="param-name">value</span> <span class="param-type">(String)</span> - Value to set</li>
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</ul>
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<pre><code>Environment.set("MY_APP_DEBUG", "true")
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System.print(Environment.get("MY_APP_DEBUG")) // true</code></pre>
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<div class="method-signature">
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<span class="method-name">Environment.delete</span>(<span class="param">name</span>)
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</div>
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<p>Deletes an environment variable.</p>
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<ul class="param-list">
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<li><span class="param-name">name</span> <span class="param-type">(String)</span> - Name of the environment variable to delete</li>
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</ul>
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<pre><code>Environment.delete("MY_APP_DEBUG")
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System.print(Environment.get("MY_APP_DEBUG")) // null</code></pre>
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<h3>Static Properties</h3>
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<div class="method-signature">
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<span class="method-name">Environment.all</span> → <span class="type">Map</span>
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</div>
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<p>Returns a map of all environment variables.</p>
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<pre><code>var env = Environment.all
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for (entry in env) {
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System.print("%(entry.key) = %(entry.value)")
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}</code></pre>
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<h2>Examples</h2>
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<h3>Reading Configuration from Environment</h3>
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<pre><code>import "env" for Environment
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var host = Environment.get("APP_HOST")
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if (host == null) host = "localhost"
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var port = Environment.get("APP_PORT")
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if (port == null) port = "8080"
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var debug = Environment.get("APP_DEBUG") == "true"
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System.print("Starting server on %(host):%(port)")
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System.print("Debug mode: %(debug)")</code></pre>
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<h3>Default Values Pattern</h3>
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<pre><code>import "env" for Environment
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class Config {
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static get(name, defaultValue) {
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var value = Environment.get(name)
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return value != null ? value : defaultValue
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}
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static getInt(name, defaultValue) {
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var value = Environment.get(name)
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if (value == null) return defaultValue
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return Num.fromString(value)
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}
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static getBool(name, defaultValue) {
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var value = Environment.get(name)
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if (value == null) return defaultValue
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return value == "true" || value == "1"
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}
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}
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var timeout = Config.getInt("TIMEOUT", 30)
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var verbose = Config.getBool("VERBOSE", false)
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var logFile = Config.get("LOG_FILE", "/var/log/app.log")
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System.print("Timeout: %(timeout)s")
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System.print("Verbose: %(verbose)")
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System.print("Log file: %(logFile)")</code></pre>
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<h3>Setting Environment for Subprocesses</h3>
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<pre><code>import "env" for Environment
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import "subprocess" for Subprocess
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Environment.set("NODE_ENV", "production")
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Environment.set("PORT", "3000")
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var result = Subprocess.run("node server.js")
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System.print(result.stdout)</code></pre>
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<h3>Listing All Environment Variables</h3>
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<pre><code>import "env" for Environment
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System.print("=== Environment Variables ===")
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var env = Environment.all
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var keys = []
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for (entry in env) {
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keys.add(entry.key)
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}
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keys.sort()
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for (key in keys) {
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System.print("%(key) = %(env[key])")</code></pre>
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<h3>Checking Required Environment Variables</h3>
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<pre><code>import "env" for Environment
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var required = ["DATABASE_URL", "API_KEY", "SECRET_KEY"]
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var missing = []
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for (name in required) {
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if (Environment.get(name) == null) {
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missing.add(name)
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}
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}
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if (missing.count > 0) {
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System.print("Missing required environment variables:")
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for (name in missing) {
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System.print(" - %(name)")
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}
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Fiber.abort("Configuration error")
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}
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System.print("All required environment variables are set")</code></pre>
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<h3>Temporary Environment Modification</h3>
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<pre><code>import "env" for Environment
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var originalPath = Environment.get("PATH")
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Environment.set("PATH", "/custom/bin:" + originalPath)
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System.print("Modified PATH for operations...")
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Environment.set("PATH", originalPath)
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System.print("Restored original PATH")</code></pre>
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<h3>Database Connection String from Environment</h3>
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<pre><code>import "env" for Environment
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var dbUrl = Environment.get("DATABASE_URL")
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if (dbUrl != null) {
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System.print("Using database: %(dbUrl)")
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} else {
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var host = Environment.get("DB_HOST")
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if (host == null) host = "localhost"
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var port = Environment.get("DB_PORT")
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if (port == null) port = "5432"
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var name = Environment.get("DB_NAME")
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if (name == null) name = "myapp"
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var user = Environment.get("DB_USER")
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if (user == null) user = "postgres"
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dbUrl = "postgres://%(user)@%(host):%(port)/%(name)"
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System.print("Constructed database URL: %(dbUrl)")
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}</code></pre>
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<div class="admonition note">
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<div class="admonition-title">Note</div>
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<p>Environment variables modified with <code>set</code> or <code>delete</code> only affect the current process and any child processes. They do not modify the parent shell's environment.</p>
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</div>
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<div class="admonition tip">
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<div class="admonition-title">Tip</div>
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<p>For configuration that may vary between environments (development, staging, production), use environment variables. This follows the twelve-factor app methodology.</p>
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</div>
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<div class="admonition warning">
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<div class="admonition-title">Warning</div>
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<p>Never log or print sensitive environment variables like API keys, passwords, or secrets. Use them directly in your application without exposing their values.</p>
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</div>
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</article>
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