README
resource-base-interface
The resource-base-interface describes resource CRUD operations which can be bound to a service. Such operations are described via a gRPC interface with the message structures therefore being defined using Protocol Buffers. This interface can be bound with any protobuf definition as long as it contains the endpoints defined in the resource-base.proto file (note that any resource message structure can be defined).
The exposed gRPC methods are implemented by the ServiceBase object which uses a ResourceAPI instance to perform operations with a database provider. The exposed interface is therefore agnostic to a specific database implementation.
However, a valid database provider is required. A set of such providers is implemented in chassis-srv.
This interface emits resource-related messages to Apache Kafka which can be enabled or disabled at the ServiceBase's constructor.
Methods for managing and traversing graph databases are supported for the ArangoDB provider
gRPC Interface
This interface describes the following gRPC endpoints for a generic resource of type Resource.
io.restorecommerce.resourcebase.Resource
| Field | Type | Label | Description |
|---|---|---|---|
| id | string | required | identifier for the resource |
| meta | io.restorecommerce.meta.Meta meta | optional | Meta information common to all Restore Commerce resources |
| value | number | optional | value for the resource |
| text | string | optional | textual data for the resource |
Create
This operation is used for inserting resources to the database.
Requests are performed by providing a list of resources which are returned in the response. A meta should be present, containing relevant resource ownership information. Timestamps for creation and modification are then appended automatically to this property upon a Create request.
The resource is stored as a normal collection document by default.
If there is a graph configuration specified for the resource then it is stored as a vertex collection along with the edge definitions provided in the configuration.
io.restorecommerce.resourcebase.ResourceList
| Field | Type | Label | Description |
|---|---|---|---|
| items | [ ] io.restorecommerce.resourcebase.Resource |
required | list of resources |
| total_count | number | optional | total number of resources |
Read
This operation returns resources based on provided filter and options.
Requests are performed using io.restorecommerce.resourcebase.ReadRequest and responses are a list of resources.
google.protobuf.Struct
| Field | Type | Label | Description |
|---|---|---|---|
| fields | map<string, Value> | optional | Unordered map of dynamically typed values. |
io.restorecommerce.resourcebase.Sort
| Field | Type | Label | Description |
|---|---|---|---|
| field | string | optional | field to be sorted upon |
| SortOrder | enum | optional | sorting order, UNSORTED, ASCENDING or DESCENDING |
io.restorecommerce.resourcebase.FieldFilter
| Field | Type | Label | Description |
|---|---|---|---|
| name | string | optional | field name |
| include | bool | optional | include or exclude field |
io.restorecommerce.resourcebase.ScopeFilter
| Field | Type | Label | Description |
|---|---|---|---|
| scope | string | optional | scope to operate on |
| instance | string | optional | value to compare |
io.restorecommerce.resourcebase.ReadRequest
| Field | Type | Label | Description |
|---|---|---|---|
| offset | number | optional | offset of the resource |
| limit | number | optional | limit, default value is 1000 |
| filter | google.protobuf.Struct | optional | filter based on field values, multiple filters can be combined with AND and OR operators |
| sort | [ ]io.restorecommerce.resourcebase.Sort |
optional | sort the resources |
| field | [ ] io.restorecommerce.resourcebase.FieldFilter |
optional | fields selector, list of fields to be included or excluded, by default we get all the fields |
| search | [ ]string | optional | word search, not yet implemeneted |
| locales_limiter | [ ]string | optional | querying based on locales, not yet implemented |
| scope | io.restorecommerce.resourcebase.ScopeFilter |
optional | scope to operate on, not yet implemented |
Update
This operation is used for updating resources in the database.
Requests are performed by providing a list of resources and all updated items are returned within the response. Note that the only required properties on each resource are its id and the properties which are meant to be modified.
It is possible to specify in the configuration multiple edge definitions for one vertex. These edges are automatically updated when vertex documents are updated.
Upsert
This operation is used for updating resources in the database or creating them if they do not exist. Requests are performed by providing a resource list, which is returned in the response.
Delete
This operation is used for deleting resources in the database.
Requests are performed using io.restorecommerce.resourcebase.DeleteRequest and responses are google.protobuf.Empty messages.
If a graph vertex is deleted, all connected edges are also deleted.
io.restorecommerce.resourcebase.DeleteRequest
| Field | Type | Label | Description |
|---|---|---|---|
| collection | string | required | Name of the target collection |
| ids | [ ]string | optional | List of resource identifiers to be deleted; if empty or not provided, the whole collection is truncated |
Traversal
This operation is used for traversing graph resource in the database.
Requests are performed using io.restorecommerce.graph.TraversalRequest and respone is io.restorecommerce.graph.TraversalResponse message.
io.restorecommerce.graph.TraversalRequest
| Field | Type | Label | Description |
|---|---|---|---|
| start_vertex | string | required | this can be either the _id or the _key of a vertex in the collection |
| opts | io.restorecommerce.graph.Options |
optional | List of options for graph traversal |
| collection_name | string | optional | starting vertex's Collection name |
| edge_name | string | optional | edge name for traversal |
| data | bool | optional | if set to true only the vertices data is returned |
| path | bool | optional | if set to true only the traversed paths are returned |
| aql | bool | optional | if set to true traversal is executed as an AQL query |
io.restorecommerce.graph.Options
| Field | Type | Label | Description |
|---|---|---|---|
| direction | string | optional | Graph traversal direction, possible values are outbound or inbound, if not provided by default it is outbound traversal |
| filter | [ ] io.restorecommerce.graph.Filter |
optional | List Vertexes to be filtered out, i.e. these vertices are not traversed |
| expander | [ ] io.restorecommerce.graph.Expander |
optional | List of edges to be included in the traversal, by default all edges are included in traversal |
| sort | string | optional | JS code of custom comparison function for the edges |
| min_depth | uint32 | optional | visits only vertices in atleast the give depth |
| start_vertex | string | optional | id of the start vertex |
| visitor | string | optional | JS code of custom visitor function |
| init | string | optional | JS code of custom result initialization function |
| item_order | string | optional | item iteration order, possible values are either forward or backward |
| strategy | string | optional | traversal strategy, possible values are either depthfirst or breadthfirst |
| max_iterations | uint32 | optional | maximum number of iterations in each traversal, this is used to prevent endless loops in cyclic graphs |
| max_depth | uint32 | optional | visits nodes in at most the given depth |
| uniqueness | io.restorecommerce.graph.Uniqueness |
optional | specifiy uniqueness for vertices and edges visited |
| order | string | optional | traversal order, possible values are preorder, postorder or preorder-expander |
| graph_name | string | optional | name of graph that contain the edges |
| edge_collection | string | optional | name of the collection that contains the edges |
io.restorecommerce.graph.Filter
| Field | Type | Label | Description |
|---|---|---|---|
| vertex | string | optional | vertex would be excluded on traversal |
io.restorecommerce.graph.Expander
| Field | Type | Label | Description |
|---|---|---|---|
| edge | string | optional | expand this edge |
| direction | string | optional | direction of traversal, either outbound or inbound |
io.restorecommerce.graph.Uniqueness
| Field | Type | Label | Description |
|---|---|---|---|
| vertices | string | optional | specifies uniqueness for vertices visited, possible values are none, global or path |
| edges | string | optional | specifies uniqueness for edges visited, possible values are none, global or path |
io.restorecommerce.graph.TraversalResponse
| Field | Type | Label | Description |
|---|---|---|---|
| vertex_fields | [ ] io.restorecommerce.graph.VertexFields |
required | Object containing vertex metadata: id, _id, _key and _rev values |
| paths | google.protobuf.Any |
required | buffered data, contains the list of visited paths |
| data | google.protobuf.Any |
required | buffered data, contains all the data from the visited vertices |
io.restorecommerce.graph.VertexFields
| Field | Type | Label | Description |
|---|---|---|---|
| _id | string | required | vertex document handle |
| _key | string | required | vertex document unique key |
| _rev | string | required | revision or vertex document ETag |
| id | string | required | id of the vertex collection |
Kafka Events
A kafka Topic can be provided when instantiating a ServiceBase. If enableEvents is set to true, a list of events is then emitted to Kafka by this microservice for each document of each CRUD request :
Created Read Modified Deleted
The events emitted to Kafka can be used for restoring the system in case of failure by implementing a command-interface in the used microservice. For usage details please see command-interface tests.
Fields Configuration
It is possible to pass a fields configuration object to ResourceAPI in order to enable some special field handlers.
Field Generators
The strategies property can be used to specify fields within each resource which should be generated automatically. Such autogeneration feature currently includes UUIDs, timestamps and sequential counters. The latter one is particularly useful for fields such as a customer or an item number, which can have a type of sequential logic. In these cases, a Redis database is used to generate and read these values efficiently.
Buffer Fields
Buffer-encoded fields can be decoded before being stored in the database. It is possible to specify within the bufferFields property what fields of each resource should be specially handled this way. The values are also encoded into a buffer again when read from the database.
Required Fields
It is possible to specify which fields are required for each document of each resource on the requiredFields config.
An InvalidArgument error is thrown if one of these fields is missing when attempting to store a document.
Development
Tests
See tests. To execute the tests a set of backing services are needed. Refer to System repository to start the backing-services before running the tests.
- To run tests
npm run test
Usage
- Install dependencies
npm install
- Build
# compile the code
npm run build