wip: add openmct-type historical api

http.go

@@ -81,11 +81,11 @@ func apiV1(broker *Broker, db *db.TelemDb) chi.Router {
 
 		})
 
-		// this is to get packets by a name.
-		r.Get("/{name:[a-z_]+}", func(w http.ResponseWriter, r *http.Request) {
-			// support field getting (matching too?)
-			// support limit
+		// this is to get a single field
+		r.Get("/{name:[a-z_]+}/{field:[a-z_]}", func(w http.ResponseWriter, r *http.Request) {
 
+			// we need a start and end time. If none is provided,
+			// we use unix epoch as start, and now + 1 day as end.
 		})
 
 	})

internal/db/getters.go

@@ -0,0 +1,49 @@
+package db
+
+import (
+	"context"
+	"strings"
+	"time"
+)
+
+// Datum is a single measurement - it is more granular than a packet.
+// the classic example is bms_measurement.current
+type Datum struct {
+	Timestamp time.Time `db:"timestamp"`
+	Value     any       `db:"val"`
+}
+
+// GetValues queries the database for values in a given time range.
+// A value is a specific data point. For example, bms_measurement.current
+// would be a value.
+func (tdb *TelemDb) GetValues(ctx context.Context, packetName, field string , start time.Time,
+	end time.Time) ([]Datum, error) {
+	// this fragment uses json_extract from sqlite to get a single
+	// nested value.
+	const SqlFrag = `
+	SELECT 
+	datetime(ts /1000.0, 'unixepoch', 'subsec') as timestamp,
+	json_extract(data, ?) as val,
+	FROM bus_events WHERE name IS ? AND timestamp BETWEEN ? AND ?
+	`
+
+	fieldJson := "$." + field
+
+	rows, err := tdb.db.QueryxContext(ctx, fieldJson, packetName, start, end)
+	defer rows.Close()
+	if err != nil {
+		return nil, err
+	}
+	data := make([]Datum, 0, 10)
+	for rows.Next() {
+		var d Datum
+		err = rows.StructScan(&d)
+		if err != nil {
+			return data, err
+		}
+		data = append(data, d)
+	}
+
+	return data, nil
+}
+

internal/db/migrations/4_import_table_up.sql

@@ -1,6 +1,6 @@
 CREATE TABLE "import_log" (
 	"filename"	TEXT NOT NULL,
-	"date"	INTEGER NOT NULL,
+	"date"	TIMESTAMP NOT NULL,
 	"count"	INTEGER NOT NULL,
 	"start_time"	INTEGER NOT NULL,
 	"end_time"	INTEGER NOT NULL

internal/logparsers/parsers.go

@@ -128,6 +128,11 @@ func parseTelemLogLine(line string) (b skylab.BusEvent, err error) {
 	}
 	ts := time.Unix(unixSeconds, unixMillis*1e6)
 
+	// VALIDATION STEP: sometimes the data gets really whack.
+	// We check that the time is between 2017 and 2032.
+	// Realistically we will not be using this software then.
+	// TODO: add this
+
 	id, err := strconv.ParseUint(a[3], 16, 16)
 	if err != nil {
 		err = NewFormatError("failed to parse id", err)