LogStream.setLevel(0);
        assertEquals(0, LogStream.level);

        // 1 - critical [default]
        LogStream.setLevel(1);
        assertEquals(1, LogStream.level);

        // 2 - basic info can be logged under load
        LogStream.setLevel(2);
        assertEquals(2, LogStream.level);

        // 3 - almost everything
        LogStream.setLevel(3);
        assertEquals(3, LogStream.level);

</div>

////

This information will be useful when learning about [Virtual Environments](virtual-environments.md){.internal-link target=_blank}.

## Conclusion { #conclusion }

With this you should have a basic understanding of what **environment variables** are and how to use them in Python.

        sourceMap.put(field, value);
    }

    // ===================================================================================
    //                                                                      Basic Override
    //                                                                      ==============
    @Override
    protected String doBuildColumnString(String dm) {
        StringBuilder sb = new StringBuilder();

        sourceMap.put(field, value);
    }

    // ===================================================================================
    //                                                                      Basic Override
    //                                                                      ==============
    @Override
    protected String doBuildColumnString(String dm) {
        StringBuilder sb = new StringBuilder();

    public abstract Map<String, Object> toSource();

    // ===================================================================================
    //                                                                      Basic Override
    //                                                                      ==============
    // #pending hashCode(), equals()
    @Override
    public int instanceHash() {
        return super.hashCode();

        if (StringUtil.isNotBlank(username) && StringUtil.isNotBlank(password)) {
            final String value = username + ":" + password;
            final String basicAuth = "Basic " + java.util.Base64.getEncoder().encodeToString(value.getBytes(StandardCharsets.UTF_8));
            request.header("Authorization", basicAuth);
        }
        if (sslSocketFactory != null) {

    public abstract Map<String, Object> toSource();

    // ===================================================================================
    //                                                                      Basic Override
    //                                                                      ==============
    // #pending hashCode(), equals()
    @Override
    public int instanceHash() {
        return super.hashCode();

application/vnd.ms-project     mpp              # MS Project
application/x-wais-source      src              # WAIS Sources
application/zip                zip jar          # ZIP Compressed File
audio/basic                    au snd           # Audio Sound File
audio/x-aiff                   aif aiff aifc    # AIFF Sound File
audio/x-midi                   mid              # MIDI Sound File

            assertEquals(24, lock.size());
        }
    }

    @Nested
    @DisplayName("Encoding Tests")
    class EncodingTests {

        @Test
        @DisplayName("Should encode basic lock structure correctly")
        void testBasicEncoding() {
            long offset = 0x1234567890ABCDEFL;
            long length = 0xFEDCBA0987654321L;
            int flags = 0x12345678;

## Deployment Concepts { #deployment-concepts }

These examples run the server program (e.g Uvicorn), starting **a single process**, listening on all the IPs (`0.0.0.0`) on a predefined port (e.g. `80`).

This is the basic idea. But you will probably want to take care of some additional things, like:

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory