From c7b398a4271c60d865691576d1513f8c318ef6ff Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Mon, 25 May 2020 11:32:34 -0400
Subject: [PATCH] Improve handling of temporary tables
---
src/_zkapauthorizer/model.py | 82 ++++++++++++++-----------
src/_zkapauthorizer/tests/test_model.py | 2 +-
2 files changed, 47 insertions(+), 37 deletions(-)
diff --git a/src/_zkapauthorizer/model.py b/src/_zkapauthorizer/model.py
index e472bd8..938fc57 100644
--- a/src/_zkapauthorizer/model.py
+++ b/src/_zkapauthorizer/model.py
@@ -148,18 +148,43 @@ def open_and_initialize(path, connect=None):
schema_upgrades = list(get_schema_upgrades(actual_version))
run_schema_upgrades(schema_upgrades, cursor)
- conn.execute("""
- -- It might already exist if there is still another connection to this
- -- database. It goes away once all connections have been closed, though.
- CREATE TABLE IF NOT EXISTS [temp.in-use] (
- [unblinded-token] text, -- The base64 encoded unblinded token.
- [operation-id] text, -- A unique identifier for a group of tokens in-use together.
-
- PRIMARY KEY([unblinded-token])
- FOREIGN KEY([unblinded-token]) REFERENCES [unblinded-tokens]([token])
+ # Create some tables that only exist (along with their contents) only for
+ # this connection. These are outside of the schema because they are not
+ # persistent. We can change them any time we like without worrying about
+ # upgrade logic because we re-create them on every connection.
+ conn.execute(
+ """
+ CREATE TEMPORARY TABLE [in-use] (
+ [unblinded-token] text, -- The base64 encoded unblinded token.
+ [operation-id] text, -- A unique identifier for a group of tokens in-use together.
+
+ PRIMARY KEY([unblinded-token])
+ -- A foreign key on unblinded-token to [unblinded-tokens]([token])
+ -- would be alright - however SQLite3 foreign key constraints
+ -- can't cross databases (and temporary tables are considered to
+ -- be in a different database than normal tables). ) """,
+ )
+ conn.execute(
+ """
+ CREATE TEMPORARY TABLE [to-discard] (
+ [unblinded-token] text
+ )
+ """,
+ )
+ conn.execute(
+ """
+ CREATE TEMPORARY TABLE [to-reset] (
+ [unblinded-token] text
+ )
+ """,
+ )
+ conn.execute(
+ """
+ CREATE TEMPORARY TABLE [extracting] (
+ [token] text
+ )
+ """,
)
- """)
-
return conn
@@ -493,10 +518,10 @@ class VoucherStore(object):
operation_id = unicode(uuid4())
cursor.execute(
"""
- INSERT INTO [temp.in-use]
+ INSERT INTO [in-use]
SELECT [token], ?
FROM [unblinded-tokens]
- WHERE [token] NOT IN (SELECT [unblinded-token] FROM [temp.in-use])
+ WHERE [token] NOT IN (SELECT [unblinded-token] FROM [in-use])
LIMIT ?
""",
(operation_id, count),
@@ -506,7 +531,7 @@ class VoucherStore(object):
cursor.execute(
"""
- SELECT [unblinded-token] FROM [temp.in-use] WHERE [operation-id] = ?
+ SELECT [unblinded-token] FROM [in-use] WHERE [operation-id] = ?
""",
(operation_id,),
)
@@ -528,12 +553,6 @@ class VoucherStore(object):
:return: ``None``
"""
- cursor.execute(
- """
- CREATE TEMPORARY TABLE [to-discard] (
- [unblinded-token] text
- )
- """)
cursor.executemany(
"""
INSERT INTO [to-discard] VALUES (?)
@@ -542,7 +561,7 @@ class VoucherStore(object):
)
cursor.execute(
"""
- DELETE FROM [temp.in-use]
+ DELETE FROM [in-use]
WHERE [unblinded-token] IN (SELECT [unblinded-token] FROM [to-discard])
""",
)
@@ -554,7 +573,7 @@ class VoucherStore(object):
)
cursor.execute(
"""
- DROP TABLE [to-discard]
+ DELETE FROM [to-discard]
""",
)
@@ -583,7 +602,7 @@ class VoucherStore(object):
)
cursor.execute(
"""
- DELETE FROM [temp.in-use]
+ DELETE FROM [in-use]
WHERE [unblinded-token] IN (SELECT [token] FROM [invalid-unblinded-tokens])
""",
)
@@ -601,13 +620,6 @@ class VoucherStore(object):
This is useful if a spending operation has failed with a transient
error.
"""
- cursor.execute(
- """
- CREATE TEMPORARY TABLE [to-reset] (
- [unblinded-token] text
- )
- """,
- )
cursor.executemany(
"""
INSERT INTO [to-reset] VALUES (?)
@@ -616,13 +628,13 @@ class VoucherStore(object):
)
cursor.execute(
"""
- DELETE FROM [temp.in-use]
+ DELETE FROM [in-use]
WHERE [unblinded-token] IN (SELECT [unblinded-token] FROM [to-reset])
""",
)
cursor.execute(
"""
- DROP TABLE [to-reset]
+ DELETE FROM [to-reset]
""",
)
@@ -649,9 +661,7 @@ class VoucherStore(object):
cursor.execute(
"""
- CREATE TEMPORARY TABLE [extracting]
- AS
- SELECT [token] FROM [unblinded-tokens] LIMIT ?
+ INSERT INTO [extracting] SELECT [token] FROM [unblinded-tokens] LIMIT ?
""",
(count,),
)
@@ -668,7 +678,7 @@ class VoucherStore(object):
texts = cursor.fetchall()
cursor.execute(
"""
- DROP TABLE [extracting]
+ DELETE FROM [extracting]
""",
)
return list(
diff --git a/src/_zkapauthorizer/tests/test_model.py b/src/_zkapauthorizer/tests/test_model.py
index c0eebae..c063324 100644
--- a/src/_zkapauthorizer/tests/test_model.py
+++ b/src/_zkapauthorizer/tests/test_model.py
@@ -551,7 +551,7 @@ class UnblindedTokenStateMachine(RuleBasedStateMachine):
with self.configless.store._connection:
self.configless.store._connection.execute(
"""
- DELETE FROM [temp.in-use]
+ DELETE FROM [in-use]
""",
)
self.available += len(self.using)
--
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