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Allow customers to assert facts about the current transaction. (#225) r=rnewman

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Also move `now` into core, implement microsecond truncation.

This is so we don't return a more granular -- and thus subtly different --
timestamp in a `TxReport` than we put into the store.
This commit is contained in:
Edouard Oger 2018-01-22 13:17:12 -05:00 committed by Richard Newman
parent 98502eb68f
commit 3bf7459315
7 changed files with 125 additions and 28 deletions
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26
core/src/lib.rs
View file

@ -233,6 +233,28 @@ impl TypedValue {
}
}
trait MicrosecondPrecision {
/// Truncate the provided `DateTime` to microsecond precision.
fn microsecond_precision(self) -> Self;
}
impl MicrosecondPrecision for DateTime<Utc> {
fn microsecond_precision(self) -> DateTime<Utc> {
let nanoseconds = self.nanosecond();
if nanoseconds % 1000 == 0 {
return self;
}
let microseconds = nanoseconds / 1000;
let truncated = microseconds * 1000;
self.with_nanosecond(truncated).expect("valid timestamp")
}
}
/// Return the current time as a UTC `DateTime` instance with microsecond precision.
pub fn now() -> DateTime<Utc> {
Utc::now().microsecond_precision()
}
// We don't do From<i64> or From<Entid> 'cos it's ambiguous.
impl From<bool> for TypedValue {
@ -245,9 +267,7 @@ impl From<bool> for TypedValue {
/// `TypedValue::Instant`.
impl From<DateTime<Utc>> for TypedValue {
fn from(value: DateTime<Utc>) -> TypedValue {
let microseconds = value.nanosecond() / 1000;
let truncated = microseconds * 1000;
TypedValue::Instant(value.with_nanosecond(truncated).expect("valid timestamp"))
TypedValue::Instant(value.microsecond_precision())
}
}

36
db/src/db.rs
View file

@ -1327,6 +1327,42 @@ mod tests {
[200 :db.schema/attribute 101]]");
}
#[test]
fn test_tx_assertions() {
let mut conn = TestConn::default();
// Test that txInstant can be asserted.
assert_transact!(conn, "[[:db/add :db/tx :db/txInstant #inst \"2017-06-16T00:56:41.257Z\"]
[:db/add 100 :db/ident :name/Ivan]
[:db/add 101 :db/ident :name/Petr]]");
assert_matches!(conn.last_transaction(),
"[[100 :db/ident :name/Ivan ?tx true]
[101 :db/ident :name/Petr ?tx true]
[?tx :db/txInstant #inst \"2017-06-16T00:56:41.257Z\" ?tx true]]");
// Test multiple txInstant with different values should fail.
assert_transact!(conn, "[[:db/add :db/tx :db/txInstant #inst \"2017-06-16T00:59:11.257Z\"]
[:db/add :db/tx :db/txInstant #inst \"2017-06-16T00:59:11.752Z\"]
[:db/add 102 :db/ident :name/Vlad]]",
Err("conflicting datoms in tx"));
// Test multiple txInstants with the same value.
assert_transact!(conn, "[[:db/add :db/tx :db/txInstant #inst \"2017-06-16T00:59:11.257Z\"]
[:db/add :db/tx :db/txInstant #inst \"2017-06-16T00:59:11.257Z\"]
[:db/add 103 :db/ident :name/Dimitri]
[:db/add 104 :db/ident :name/Anton]]");
assert_matches!(conn.last_transaction(),
"[[103 :db/ident :name/Dimitri ?tx true]
[104 :db/ident :name/Anton ?tx true]
[?tx :db/txInstant #inst \"2017-06-16T00:59:11.257Z\" ?tx true]]");
// Test txInstant retraction
// Test disabled: retracting a datom that doesn't exist should fail.
// assert_transact!(conn, "[[:db/retract :db/tx :db/txInstant #inst \"2017-06-16T00:59:11.257Z\"]
// [:db/add 105 :db/ident :name/Vadim]]",
// Err("Should fail!"));
}
#[test]
fn test_retract() {
let mut conn = TestConn::default();

5
db/src/errors.rs
View file

@ -82,5 +82,10 @@ error_chain! {
description("unrecognized or no ident found for entid")
display("unrecognized or no ident found for entid: {}", entid)
}
ConflictingDatoms {
description("conflicting datoms in tx")
display("conflicting datoms in tx")
}
}
}

13
db/src/lib.rs
View file

@ -8,6 +8,9 @@
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
// Oh, error_chain.
#![recursion_limit="128"]
#[macro_use]
extern crate error_chain;
extern crate itertools;
@ -28,11 +31,6 @@ use std::iter::repeat;
use itertools::Itertools;
use mentat_core::{
DateTime,
Utc,
};
pub use errors::{Error, ErrorKind, ResultExt, Result};
pub mod db;
@ -116,8 +114,3 @@ pub fn repeat_values(values_per_tuple: usize, tuples: usize) -> String {
let values: String = repeat(inner).take(tuples).join(", ");
values
}
/// Return the current time as a UTC `DateTime` instance.
pub fn now() -> DateTime<Utc> {
Utc::now()
}

60
db/src/tx.rs
View file

@ -85,6 +85,7 @@ use mentat_core::{
Schema,
Utc,
attribute,
now,
};
use mentat_core::intern_set::InternSet;
@ -141,7 +142,7 @@ pub struct Tx<'conn, 'a> {
tx_id: Entid,
/// The timestamp when the transaction began to be committed.
tx_instant: DateTime<Utc>,
tx_instant: Option<DateTime<Utc>>,
}
impl<'conn, 'a> Tx<'conn, 'a> {
@ -150,15 +151,14 @@ impl<'conn, 'a> Tx<'conn, 'a> {
partition_map: PartitionMap,
schema_for_mutation: &'a Schema,
schema: &'a Schema,
tx_id: Entid,
tx_instant: DateTime<Utc>) -> Tx<'conn, 'a> {
tx_id: Entid) -> Tx<'conn, 'a> {
Tx {
store: store,
partition_map: partition_map,
schema_for_mutation: Cow::Borrowed(schema_for_mutation),
schema: schema,
tx_id: tx_id,
tx_instant: tx_instant,
tx_instant: None,
}
}
@ -206,16 +206,18 @@ impl<'conn, 'a> Tx<'conn, 'a> {
partition_map: &'a PartitionMap,
schema: &'a Schema,
mentat_id_count: i64,
tx_id: KnownEntid,
temp_ids: InternSet<TempId>,
lookup_refs: InternSet<AVPair>,
}
impl<'a> InProcess<'a> {
fn with_schema_and_partition_map(schema: &'a Schema, partition_map: &'a PartitionMap) -> InProcess<'a> {
fn with_schema_and_partition_map(schema: &'a Schema, partition_map: &'a PartitionMap, tx_id: KnownEntid) -> InProcess<'a> {
InProcess {
partition_map,
schema,
mentat_id_count: 0,
tx_id,
temp_ids: InternSet::new(),
lookup_refs: InternSet::new(),
}
@ -269,6 +271,11 @@ impl<'conn, 'a> Tx<'conn, 'a> {
Ok(Either::Left(e))
},
// Special case: current tx ID.
entmod::EntidOrLookupRefOrTempId::TempId(TempId::Tx) => {
Ok(Either::Left(self.tx_id))
},
entmod::EntidOrLookupRefOrTempId::TempId(e) => {
Ok(Either::Right(LookupRefOrTempId::TempId(self.intern_temp_id(e))))
},
@ -334,7 +341,7 @@ impl<'conn, 'a> Tx<'conn, 'a> {
}
}
let mut in_process = InProcess::with_schema_and_partition_map(&self.schema, &self.partition_map);
let mut in_process = InProcess::with_schema_and_partition_map(&self.schema, &self.partition_map, KnownEntid(self.tx_id));
// We want to handle entities in the order they're given to us, while also "exploding" some
// entities into many. We therefore push the initial entities onto the back of the deque,
@ -593,6 +600,8 @@ impl<'conn, 'a> Tx<'conn, 'a> {
final_populations.allocated,
inert_terms.into_iter().map(|term| term.unwrap()).collect()].concat();
let tx_instant;
{ // TODO: Don't use this block to scope borrowing the schema; instead, extract a helper function.
// Assertions that are :db.cardinality/one and not :db.fulltext.
@ -615,14 +624,37 @@ impl<'conn, 'a> Tx<'conn, 'a> {
// TODO: use something like Clojure's group_by to do this.
for term in final_terms {
match term {
Term::AddOrRetract(op, e, a, v) => {
Term::AddOrRetract(op, KnownEntid(e), a, v) => {
let attribute: &Attribute = self.schema.require_attribute_for_entid(a)?;
if entids::might_update_metadata(a) {
tx_might_update_metadata = true;
}
let added = op == OpType::Add;
let reduced = (e.0, a, attribute, v, added);
// We take the last encountered :db/txInstant value.
// If more than one is provided, the transactor will fail.
if added &&
e == self.tx_id &&
a == entids::DB_TX_INSTANT {
if let TypedValue::Instant(instant) = v {
if let Some(ts) = self.tx_instant {
if ts == instant {
// Dupes are fine.
} else {
bail!(ErrorKind::ConflictingDatoms);
}
} else {
self.tx_instant = Some(instant);
}
continue;
} else {
// The type error has been caught earlier.
unreachable!()
}
}
let reduced = (e, a, attribute, v, added);
match (attribute.fulltext, attribute.multival) {
(false, true) => non_fts_many.push(reduced),
(false, false) => non_fts_one.push(reduced),
@ -633,12 +665,13 @@ impl<'conn, 'a> Tx<'conn, 'a> {
}
}
// Transact [:db/add :db/txInstant NOW :db/tx].
// TODO: allow this to be present in the transaction data.
tx_instant = self.tx_instant.unwrap_or_else(now);
// Transact [:db/add :db/txInstant tx_instant :db/tx].
non_fts_one.push((self.tx_id,
entids::DB_TX_INSTANT,
self.schema.require_attribute_for_entid(entids::DB_TX_INSTANT).unwrap(),
TypedValue::Instant(self.tx_instant),
tx_instant.into(),
true));
if !non_fts_one.is_empty() {
@ -683,7 +716,7 @@ impl<'conn, 'a> Tx<'conn, 'a> {
Ok(TxReport {
tx_id: self.tx_id,
tx_instant: self.tx_instant,
tx_instant,
tempids: tempids,
})
}
@ -694,12 +727,11 @@ fn start_tx<'conn, 'a>(conn: &'conn rusqlite::Connection,
mut partition_map: PartitionMap,
schema_for_mutation: &'a Schema,
schema: &'a Schema) -> Result<Tx<'conn, 'a>> {
let tx_instant = ::now(); // Label the transaction with the timestamp when we first see it: leading edge.
let tx_id = partition_map.allocate_entid(":db.part/tx");
conn.begin_tx_application()?;
Ok(Tx::new(conn, partition_map, schema_for_mutation, schema, tx_id, tx_instant))
Ok(Tx::new(conn, partition_map, schema_for_mutation, schema, tx_id))
}
fn conclude_tx(tx: Tx, report: TxReport) -> Result<(TxReport, PartitionMap, Option<Schema>)> {

9
tx-parser/src/lib.rs
View file

@ -89,11 +89,18 @@ def_parser!(Tx, lookup_ref, LookupRef, {
});
def_parser!(Tx, entid_or_lookup_ref_or_temp_id, EntidOrLookupRefOrTempId, {
Tx::entid().map(EntidOrLookupRefOrTempId::Entid)
Tx::db_tx().map(EntidOrLookupRefOrTempId::TempId)
.or(Tx::entid().map(EntidOrLookupRefOrTempId::Entid))
.or(Tx::lookup_ref().map(EntidOrLookupRefOrTempId::LookupRef))
.or(Tx::temp_id().map(EntidOrLookupRefOrTempId::TempId))
});
def_matches_namespaced_keyword!(Tx, literal_db_tx, "db", "tx");
def_parser!(Tx, db_tx, TempId, {
Tx::literal_db_tx().map(|_| TempId::Tx)
});
def_parser!(Tx, temp_id, TempId, {
satisfy_map(|x: &'a edn::ValueAndSpan| x.as_text().cloned().map(TempId::External))
});

4
tx/src/entities.rs
View file

@ -23,12 +23,14 @@ use self::edn::symbols::NamespacedKeyword;
pub enum TempId {
External(String),
Internal(i64),
Tx, // Special identifier used to refer to the current transaction.
}
impl TempId {
pub fn into_external(self) -> Option<String> {
match self {
TempId::External(s) => Some(s),
TempId::Tx |
TempId::Internal(_) => None,
}
}
@ -36,6 +38,7 @@ impl TempId {
pub fn into_internal(self) -> Option<i64> {
match self {
TempId::Internal(x) => Some(x),
TempId::Tx |
TempId::External(_) => None,
}
}
@ -46,6 +49,7 @@ impl fmt::Display for TempId {
match self {
&TempId::External(ref s) => write!(f, "{}", s),
&TempId::Internal(x) => write!(f, "<tempid {}>", x),
&TempId::Tx => write!(f, "<Tx>"),
}
}
}