gotelem/db.go
2023-06-30 07:40:50 -05:00

250 lines
6.5 KiB
Go

package gotelem
// this file implements the database functions to load/store/read from a sql database.
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"strconv"
"strings"
"time"
"github.com/jmoiron/sqlx"
"github.com/kschamplin/gotelem/skylab"
sqlite3 "github.com/mattn/go-sqlite3"
)
func init() {
sql.Register("custom_sqlite3", &sqlite3.SQLiteDriver{
// TODO: add functions that convert between unix milliseconds and ISO 8601
})
}
type TelemDb struct {
db *sqlx.DB
}
type TelemDbOption func(*TelemDb) error
func OpenTelemDb(path string, options ...TelemDbOption) (tdb *TelemDb, err error) {
tdb = &TelemDb{}
tdb.db, err = sqlx.Connect("sqlite3", path)
if err != nil {
return
}
// TODO: add options support.
for _, fn := range options {
err = fn(tdb)
if err != nil {
return
}
}
// execute database up statement (better hope it is idempotent!)
// FIXME: only do this when it's a new database (instead warn the user about potential version mismatches)
// TODO: store gotelem version (commit hash?) in DB (PRAGMA user_version)
_, err = tdb.db.Exec(sqlDbUp)
return tdb, err
}
// the sql commands to create the database.
const sqlDbUp = `
CREATE TABLE IF NOT EXISTS "bus_events" (
"ts" INTEGER NOT NULL, -- timestamp, unix milliseconds
"id" INTEGER NOT NULL, -- can ID
"name" TEXT NOT NULL, -- name of base packet
"data" TEXT NOT NULL CHECK(json_valid(data)) -- JSON object describing the data, including index if any
);
CREATE INDEX IF NOT EXISTS "ids_timestamped" ON "bus_events" (
"id",
"ts" DESC
);
CREATE INDEX IF NOT EXISTS "times" ON "bus_events" (
"ts" DESC
);
-- this table shows when we started/stopped logging.
CREATE TABLE "drive_records" (
"id" INTEGER NOT NULL UNIQUE, -- unique ID of the drive.
"start_time" INTEGER NOT NULL, -- when the drive started
"end_time" INTEGER, -- when it ended, or NULL if it's ongoing.
"note" TEXT, -- optional description of the segment/experiment/drive
PRIMARY KEY("id" AUTOINCREMENT),
CONSTRAINT "duration_valid" CHECK(end_time is null or start_time < end_time)
);
-- gps logs TODO: use GEOJSON/Spatialite tracks instead?
CREATE TABLE "position_logs" (
"ts" INTEGER NOT NULL,
"source" TEXT NOT NULL,
"lat" REAL NOT NULL,
"lon" REAL NOT NULL,
"elevation" REAL,
CONSTRAINT "no_empty_source" CHECK(source is not "")
);
-- TODO: ensure only one "active" (end_time == null) drive record at a time using triggers/constraints/index
`
// sql sequence to tear down the database.
// not used often, but good to keep track of what's going on.
// Up() then Down() should result in an empty database.
const sqlDbDown = `
DROP TABLE "bus_events";
DROP INDEX "ids_timestamped";
DROP INDEX "times";
DROP TABLE "drive_records";
DROP TABLE "position_logs";
`
// sql expression to insert a bus event into the packets database.1
const sqlInsertEvent = `
INSERT INTO "bus_events" (time, can_id, name, packet) VALUES ($1, $2, $3, json($4));
`
// AddEvent adds the bus event to the database.
func (tdb *TelemDb) AddEventsCtx(ctx context.Context, events ...skylab.BusEvent) (err error) {
//
tx, err := tdb.db.BeginTx(ctx, nil)
if err != nil {
tx.Rollback()
return
}
for _, b := range events {
var j []byte
j, err = json.Marshal(b.Data)
if err != nil {
tx.Rollback()
return
}
tx.ExecContext(ctx, sqlInsertEvent, b.Timestamp.UnixMilli(), b.Id, b.Data.String(), j)
}
tx.Commit()
return
}
func (tdb *TelemDb) AddEvents(events ...skylab.BusEvent) (err error) {
return tdb.AddEventsCtx(context.Background(), events...)
}
/// Query fragment guide:
/// We need to be able to easily construct safe(!) and meaningful queries programatically
/// so we make some new types that can be turned into SQL fragments that go inside the where clause.
/// These all implement the QueryFrag interface, meaning the actual query function (that acts on the DB)
/// can deal with them agnostically. The Query function joins all the fragments it is given with AND.
/// to get OR,
// QueryFrag is anything that can be turned into a Query WHERE clause
type QueryFrag interface {
Query() string
}
// QueryIdRange represents a range of IDs to select for, inclusive.
type QueryIdRange struct {
Start uint32
End uint32
}
func (q *QueryIdRange) Query() string {
return fmt.Sprintf("id BETWEEN %d AND %d", q.Start, q.End)
}
// QueryIds selects for individual CAN ids
type QueryIds []uint32
func (q QueryIds) Query() string {
var idStrings []string
for _, id := range q {
idStrings = append(idStrings, strconv.FormatUint(uint64(id), 10))
}
return fmt.Sprintf("id IN (%s)", strings.Join(idStrings, ","))
}
// QueryTimeRange represents a query of a specific time range. For "before" or "after" queries,
// use time.Unix(0,0) or time.Now() in start and end respectively.
type QueryTimeRange struct {
Start time.Time
End time.Time
}
func (q *QueryTimeRange) Query() string {
startUnix := q.Start.UnixMilli()
endUnix := q.End.UnixMilli()
return fmt.Sprintf("ts BETWEEN %d AND %d", startUnix, endUnix)
}
type QueryNames []string
func (q QueryNames) Query() string {
return fmt.Sprintf("name IN (%s)", strings.Join(q, ", "))
}
type QueryOr []QueryFrag
func (q QueryOr) Query() string {
var qStrings []string
for _, frag := range q {
qStrings = append(qStrings, frag.Query())
}
return fmt.Sprintf("(%s)", strings.Join(qStrings, " OR "))
}
const eventQueryFmtString = `SELECT * FROM "bus_events" WHERE %s LIMIT %d`
// GetEvents is the mechanism to request underlying event data.
// it takes functions (which are defined in db.go) that modify the query,
// and then return the results.
func (tdb *TelemDb) GetEvents(limit int, where ...QueryFrag) (events []skylab.BusEvent, err error) {
// Simple mechanism for combining query frags:
// join with " AND ". To join expressions with or, use QueryOr
var fragStr []string
for _, f := range where {
fragStr = append(fragStr, f.Query())
}
qString := fmt.Sprintf("SELECT * FROM \"bus_events\" WHERE %s LIMIT %d", strings.Join(fragStr, " AND "), limit)
rows, err := tdb.db.Queryx(qString)
if err != nil {
return
}
defer rows.Close()
if limit < 0 { // special case: limit negative means unrestricted.
events = make([]skylab.BusEvent, 0, 20)
} else {
events = make([]skylab.BusEvent, 0, limit)
}
// scan rows into busevent list...
for rows.Next() {
var ev skylab.RawJsonEvent
err = rows.StructScan(&ev)
if err != nil {
return
}
BusEv := skylab.BusEvent{
Timestamp: time.UnixMilli(int64(ev.Timestamp)),
Id: ev.Id,
}
BusEv.Data, err = skylab.FromJson(ev.Id, ev.Data)
// FIXME: this is slow!
events = append(events, BusEv)
}
err = rows.Err()
return
}