Enable contract listeners with multiple filters

.vscode/launch.json

@@ -23,7 +23,7 @@
       "program": "${workspaceFolder}/main.go",
       "args": [
         "-f",
-        "${env:HOME}/.firefly/stacks/dev/runtime/config/firefly_core_0.yml"
+        "${env:HOME}/.firefly/stacks/listeners/runtime/config/firefly_core_0.yml"
       ]
     }
   ]

db/migrations/postgres/000117_update_contractlisteners_add_filters_column.down.sql

@@ -0,0 +1,5 @@
+BEGIN;
+ALTER TABLE contractlisteners DROP COLUMN filters;
+DROP INDEX contractlisteners_filter_hash;
+ALTER TABLE contractlisteners DROP COLUMN filter_hash;
+COMMIT;

db/migrations/postgres/000117_update_contractlisteners_add_filters_column.up.sql

@@ -0,0 +1,8 @@
+BEGIN;
+ALTER TABLE contractlisteners ADD COLUMN filters TEXT;
+ALTER TABLE contractlisteners ALTER COLUMN event DROP NOT NULL;
+ALTER TABLE contractlisteners ALTER COLUMN location DROP NOT NULL;
+ALTER TABLE contractlisteners ALTER COLUMN signature DROP NOT NULL;
+ALTER TABLE contractlisteners ADD COLUMN filter_hash CHAR(64);
+CREATE INDEX contractlisteners_filter_hash ON contractlisteners(filter_hash);
+COMMIT:

db/migrations/sqlite/000117_update_contractlisteners_add_filters_column.down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE contractlisteners DROP COLUMN filters;
+DROP INDEX contractlisteners_filter_hash;
+ALTER TABLE contractlisteners DROP COLUMN filter_hash;

db/migrations/sqlite/000117_update_contractlisteners_add_filters_column.up.sql

@@ -0,0 +1,14 @@
+ALTER TABLE contractlisteners ADD COLUMN filters TEXT;
+ALTER TABLE contractlisteners ADD COLUMN filter_hash CHAR(64);
+CREATE INDEX contractlisteners_filter_hash ON contractlisteners(filter_hash);
+
+-- SQLite doesn't support dropping NOT NULL constraints so we have to move
+-- everything to a temp colum, create a new column, then copy the data back
+ALTER TABLE contractlisteners RENAME COLUMN event TO event_tmp;
+ALTER TABLE contractlisteners RENAME COLUMN location TO location_tmp;
+ALTER TABLE contractlisteners ADD COLUMN event TEXT;
+ALTER TABLE contractlisteners ADD LOCATION event TEXT;
+UPDATE contractlisteners SET event = event_tmp;
+UPDATE contractlisteners SET location = location_tmp;
+ALTER TABLE contractlisteners DROP COLUMN event_tmp;
+ALTER TABLE contractlisteners DROP COLUMN location_tmp;

docs/reference/types/contractlistener.md

@@ -64,16 +64,18 @@ nav_order: 10
 | Field Name | Description | Type |
 |------------|-------------|------|
 | `id` | The UUID of the smart contract listener | [`UUID`](simpletypes#uuid) |
-| `interface` | A reference to an existing FFI, containing pre-registered type information for the event | [`FFIReference`](#ffireference) |
+| `interface` | Deprecated: Please use 'interface' in the array of 'filters' instead | [`FFIReference`](#ffireference) |
 | `namespace` | The namespace of the listener, which defines the namespace of all blockchain events detected by this listener | `string` |
 | `name` | A descriptive name for the listener | `string` |
 | `backendId` | An ID assigned by the blockchain connector to this listener | `string` |
-| `location` | A blockchain specific contract identifier. For example an Ethereum contract address, or a Fabric chaincode name and channel | [`JSONAny`](simpletypes#jsonany) |
+| `location` | Deprecated: Please use 'location' in the array of 'filters' instead | [`JSONAny`](simpletypes#jsonany) |
 | `created` | The creation time of the listener | [`FFTime`](simpletypes#fftime) |
-| `event` | The definition of the event, either provided in-line when creating the listener, or extracted from the referenced FFI | [`FFISerializedEvent`](#ffiserializedevent) |
+| `event` | Deprecated: Please use 'event' in the array of 'filters' instead | [`FFISerializedEvent`](#ffiserializedevent) |
 | `signature` | The stringified signature of the event, as computed by the blockchain plugin | `string` |
 | `topic` | A topic to set on the FireFly event that is emitted each time a blockchain event is detected from the blockchain. Setting this topic on a number of listeners allows applications to easily subscribe to all events they need | `string` |
 | `options` | Options that control how the listener subscribes to events from the underlying blockchain | [`ContractListenerOptions`](#contractlisteneroptions) |
+| `filters` | A list of filters for the contract listener. Each filter is made up of an Event and an optional Location. Events matching these filters will always be emitted in the order determined by the blockchain. | [`ListenerFilter[]`](#listenerfilter) |
+| `filterHash` | This is the hash of the filters provided, useful to be able to retrieve a unique contract listener. | `Bytes32` |
 
 ## FFIReference
 
@@ -109,3 +111,13 @@ nav_order: 10
 | `firstEvent` | A blockchain specific string, such as a block number, to start listening from. The special strings 'oldest' and 'newest' are supported by all blockchain connectors. Default is 'newest' | `string` |
 
 
+## ListenerFilter
+
+| Field Name | Description | Type |
+|------------|-------------|------|
+| `event` | The definition of the event, either provided in-line when creating the listener, or extracted from the referenced FFI | [`FFISerializedEvent`](#ffiserializedevent) |
+| `location` | A blockchain specific contract identifier. For example an Ethereum contract address, or a Fabric chaincode name and channel | [`JSONAny`](simpletypes#jsonany) |
+| `interface` | A reference to an existing FFI, containing pre-registered type information for the event | [`FFIReference`](#ffireference) |
+| `signature` | The stringified signature of the event, as computed by the blockchain plugin | `string` |
+
+