rename gps303 -> loctrkd

[loctrkd.git] / loctrkd / evstore.py

diff --git a/loctrkd/evstore.py b/loctrkd/evstore.py
new file mode 100644 (file)
index 0000000..07b6dc4
--- /dev/null
+++ b/loctrkd/evstore.py
@@ -0,0 +1,76 @@
+""" sqlite event store """
+
+from sqlite3 import connect, OperationalError
+from typing import Any, List, Tuple
+
+__all__ = "fetch", "initdb", "stow"
+
+DB = None
+
+SCHEMA = """create table if not exists events (
+    tstamp real not null,
+    imei text,
+    peeraddr text not null,
+    is_incoming int not null default TRUE,
+    proto text not null,
+    packet blob
+)"""
+
+
+def initdb(dbname: str) -> None:
+    global DB
+    DB = connect(dbname)
+    try:
+        DB.execute(
+            """alter table events add column
+                is_incoming int not null default TRUE"""
+        )
+    except OperationalError:
+        DB.execute(SCHEMA)
+
+
+def stow(**kwargs: Any) -> None:
+    assert DB is not None
+    parms = {
+        k: kwargs[k] if k in kwargs else v
+        for k, v in (
+            ("is_incoming", True),
+            ("peeraddr", None),
+            ("when", 0.0),
+            ("imei", None),
+            ("proto", "UNKNOWN"),
+            ("packet", b""),
+        )
+    }
+    assert len(kwargs) <= len(parms)
+    DB.execute(
+        """insert or ignore into events
+                (tstamp, imei, peeraddr, proto, packet, is_incoming)
+                values
+                (:when, :imei, :peeraddr, :proto, :packet, :is_incoming)
+        """,
+        parms,
+    )
+    DB.commit()
+
+
+def fetch(
+    imei: str, matchlist: List[Tuple[bool, str]], backlog: int
+) -> List[Tuple[bool, float, bytes]]:
+    # matchlist is a list of tuples (is_incoming, proto)
+    # returns a list of tuples (is_incoming, timestamp, packet)
+    assert DB is not None
+    selector = " or ".join(
+        (f"(is_incoming = ? and proto = ?)" for _ in range(len(matchlist)))
+    )
+    cur = DB.cursor()
+    cur.execute(
+        f"""select is_incoming, tstamp, packet from events
+                    where ({selector}) and imei = ?
+                    order by tstamp desc limit ?""",
+        tuple(item for sublist in matchlist for item in sublist)
+        + (imei, backlog),
+    )
+    result = list(cur)
+    cur.close()
+    return list(reversed(result))