cloud: Expose operational and archive databases

Introduce the concepts of "operational database" and "archive database".

The "operational database" is the one where most operations are done,
and which has recent data only, as opposed to "archive database", which
keeps all the data, but is either slow or expensive to query. In our
case the former is PostgreSQL and the latter is BigQuery.

Export the operational database specification to Cloud Functions as
"KCIDB_OPERATIONAL_DATABASE", and the archive database as
"KCIDB_ARCHIVE_DATABASE".

cloud

@@ -263,6 +263,8 @@ function execute_command() {
         --smtp-topic="$smtp_topic"
         --smtp-subscription="$smtp_subscription"
         --pgpass-secret="$psql_pgpass_secret"
+        --op-database="$psql_kcidb_db"
+        --ar-database="$bigquery_kcidb_db"
         --database="$database"
         --clean-test-databases="$clean_test_databases"
         --empty-test-databases="$empty_test_databases"

kcidb/cloud/cloud_functions.sh

@@ -24,6 +24,8 @@ declare _CLOUD_FUNCTIONS_SH=
 #       --smtp-to-addrs=ADDRS --smtp-password-secret=NAME
 #       --smtp-topic=NAME --smtp-subscription=NAME
 #       --pgpass-secret=NAME
+#       --op-database=SPEC
+#       --ar-database=SPEC
 #       --database=SPEC
 #       --clean-test-databases=SPEC_LIST
 #       --empty-test-databases=SPEC_LIST
@@ -44,6 +46,8 @@ function cloud_functions_env() {
                           pgpass_secret \
                           cache_bucket_name \
                           cache_redirector_url \
+                          op_database \
+                          ar_database \
                           database \
                           clean_test_databases \
                           empty_test_databases \
@@ -59,6 +63,8 @@ function cloud_functions_env() {
         [KCIDB_LOAD_QUEUE_OBJ_MAX]="8192"
         [KCIDB_LOAD_QUEUE_TIMEOUT_SEC]="30"
         [KCIDB_PGPASS_SECRET]="$pgpass_secret"
+        [KCIDB_OPERATIONAL_DATABASE]="$op_database"
+        [KCIDB_ARCHIVE_DATABASE]="$ar_database"
         [KCIDB_DATABASE]="$database"
         [KCIDB_DATABASE_LOAD_PERIOD_SEC]="180"
         [KCIDB_CLEAN_TEST_DATABASES]="$clean_test_databases"

main.py

@@ -28,6 +28,12 @@
 # Maximum time for pulling maximum amount of submissions from the queue
 LOAD_QUEUE_TIMEOUT_SEC = float(os.environ["KCIDB_LOAD_QUEUE_TIMEOUT_SEC"])
 
+# The specification for the operational database (a part of DATABASE spec)
+OPERATIONAL_DATABASE = os.environ["KCIDB_OPERATIONAL_DATABASE"]
+
+# The specification for the archive database (a part of DATABASE spec)
+ARCHIVE_DATABASE = os.environ["KCIDB_ARCHIVE_DATABASE"]
+
 # The specification for the database submissions should be loaded into
 DATABASE = os.environ["KCIDB_DATABASE"]