Refactor and split out things into cmd and lib (#77)

* Refactor anubis to split business logic into a lib, and cmd to just be direct usage.

* Post-rebase fixes.

* Update changelog, remove unnecessary one.

* lib: refactor this

This is mostly based on my personal preferences for how Go code should
be laid out. I'm not sold on the package name "lib" (I'd call it anubis
but that would stutter), but people are probably gonna import it as
libanubis so it's likely fine.

Packages have been "flattened" to centralize implementation with area of
concern. This goes against the Java-esque style that many people like,
but I think this helps make things simple.

Most notably: the dnsbl client (which is a hack) is an internal package
until it's made more generic. Then it can be made external.

I also fixed the logic such that `go generate` works and rebased on
main.

* internal/test: run tests iff npx exists and DONT_USE_NETWORK is not set

Signed-off-by: Xe Iaso <me@xeiaso.net>

* internal/test: install deps

Signed-off-by: Xe Iaso <me@xeiaso.net>

* .github/workflows: verbose go tests?

Signed-off-by: Xe Iaso <me@xeiaso.net>

* internal/test: sleep 2

Signed-off-by: Xe Iaso <me@xeiaso.net>

* internal/test: nix this test so CI works

Signed-off-by: Xe Iaso <me@xeiaso.net>

* internal/test: warmup per browser?

Signed-off-by: Xe Iaso <me@xeiaso.net>

* internal/test: disable for now :(

Signed-off-by: Xe Iaso <me@xeiaso.net>

* lib/anubis: do not apply bot rules if address check fails

Closes #83

---------

Signed-off-by: Xe Iaso <me@xeiaso.net>
Co-authored-by: Xe Iaso <me@xeiaso.net>

decaymap/decaymap.go

@@ -0,0 +1,87 @@
+package decaymap
+
+import (
+	"sync"
+	"time"
+)
+
+func Zilch[T any]() T {
+	var zero T
+	return zero
+}
+
+// Impl is a lazy key->value map. It's a wrapper around a map and a mutex. If values exceed their time-to-live, they are pruned at Get time.
+type Impl[K comparable, V any] struct {
+	data map[K]decayMapEntry[V]
+	lock sync.RWMutex
+}
+
+type decayMapEntry[V any] struct {
+	Value  V
+	expiry time.Time
+}
+
+// New creates a new DecayMap of key type K and value type V.
+//
+// Key types must be comparable to work with maps.
+func New[K comparable, V any]() *Impl[K, V] {
+	return &Impl[K, V]{
+		data: make(map[K]decayMapEntry[V]),
+	}
+}
+
+// expire forcibly expires a key by setting its time-to-live one second in the past.
+func (m *Impl[K, V]) expire(key K) bool {
+	m.lock.RLock()
+	val, ok := m.data[key]
+	m.lock.RUnlock()
+
+	if !ok {
+		return false
+	}
+
+	m.lock.Lock()
+	val.expiry = time.Now().Add(-1 * time.Second)
+	m.data[key] = val
+	m.lock.Unlock()
+
+	return true
+}
+
+// Get gets a value from the DecayMap by key.
+//
+// If a value has expired, forcibly delete it if it was not updated.
+func (m *Impl[K, V]) Get(key K) (V, bool) {
+	m.lock.RLock()
+	value, ok := m.data[key]
+	m.lock.RUnlock()
+
+	if !ok {
+		return Zilch[V](), false
+	}
+
+	if time.Now().After(value.expiry) {
+		m.lock.Lock()
+		// Since previously reading m.data[key], the value may have been updated.
+		// Delete the entry only if the expiry time is still the same.
+		if m.data[key].expiry == value.expiry {
+			delete(m.data, key)
+		}
+		m.lock.Unlock()
+
+		return Zilch[V](), false
+	}
+
+	return value.Value, true
+}
+
+// Set sets a key value pair in the map.
+func (m *Impl[K, V]) Set(key K, value V, ttl time.Duration) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	m.data[key] = decayMapEntry[V]{
+		Value:  value,
+		expiry: time.Now().Add(ttl),
+	}
+}

decaymap/decaymap_test.go

@@ -0,0 +1,31 @@
+package decaymap
+
+import (
+	"testing"
+	"time"
+)
+
+func TestImpl(t *testing.T) {
+	dm := New[string, string]()
+
+	dm.Set("test", "hi", 5*time.Minute)
+
+	val, ok := dm.Get("test")
+	if !ok {
+		t.Error("somehow the test key was not set")
+	}
+
+	if val != "hi" {
+		t.Errorf("wanted value %q, got: %q", "hi", val)
+	}
+
+	ok = dm.expire("test")
+	if !ok {
+		t.Error("somehow could not force-expire the test key")
+	}
+
+	_, ok = dm.Get("test")
+	if ok {
+		t.Error("got value even though it was supposed to be expired")
+	}
+}