|
| 1 | +# Vendor-Configurable Metadata Models |
| 2 | + |
| 3 | +This document illustrates the limitations originate from the metadata models in the DANDI ecosystem with |
| 4 | +[dandi-schema](https://github.com/dandi/dandi-schema) before version 0.12.0 and outlines the solution |
| 5 | +of vendor-configurable metadata models implemented across multiple components of the ecosystem, |
| 6 | +with the implementation starting and coordinated with dandi-schema at v0.12.0, to overcome these |
| 7 | +limitations. |
| 8 | + |
| 9 | +## Limitations |
| 10 | + |
| 11 | +The current metadata models and their uses in the DANDI ecosystem have the following limitations: |
| 12 | + |
| 13 | +1. We do not actually support or use multiple versions of the metadata models in dandi-archive. |
| 14 | +2. We use two representations of metadata models – Pydantic models and their respective JSON Schema derivatives – and |
| 15 | + rely on an external process to generate the JSON Schema representation from the Pydantic models. |
| 16 | +3. We manually trigger updates of web frontend files according to a specific version of the JSON Schema representation of the models. |
| 17 | +4. We hardcode vendor-specific information inside the dandi-archive codebase (backend and frontend). |
| 18 | +5. Any vendor-specific configuration done at runtime in Pydantic models is not reflected in the JSON Schema representation used |
| 19 | + by the web frontend since the web frontend uses a static versioned JSON Schema representation stored at |
| 20 | + [dandi/schema](https://github.com/dandi/schema) that has been generated by the external process mentioned in point 2. |
| 21 | + |
| 22 | +```mermaid |
| 23 | +flowchart TD |
| 24 | + %% repositories as grouped nodes |
| 25 | + subgraph dandi_schema_repo["<a href='https://github.com/dandi/dandi-schema/'>dandi/dandi-schema</a>"] |
| 26 | + Pydantic["Pydantic Models"] |
| 27 | + end |
| 28 | +
|
| 29 | + subgraph schema_repo["<a href='https://github.com/dandi/schema/'>dandi/schema</a>"] |
| 30 | + JSONSchema["JSON Schema<br>serializations"] |
| 31 | +
|
| 32 | + end |
| 33 | +
|
| 34 | + subgraph dandi_cli_repo["<a href='https://github.com/dandi/dandi-cli'>dandi-cli</a>"] |
| 35 | + CLI["CLI & Library<br>validation logic<br/>(Python)"] |
| 36 | + end |
| 37 | +
|
| 38 | + subgraph dandi_archive_repo["<a href='https://github.com/dandi/dandi-archive/'>dandi-archive</a>"] |
| 39 | + Meditor["Web UI<br/>Metadata Editor<br/>(meditor; Vue)"] |
| 40 | + API["Archive API<br/>(Python; DJANGO)"] |
| 41 | + Storage[("DB (Postgresql)")] |
| 42 | + end |
| 43 | +
|
| 44 | + %% main flow |
| 45 | + Pydantic -->|"serialize into<br/>(CI)"| JSONSchema |
| 46 | + Pydantic -->|used to validate| CLI |
| 47 | + Pydantic -->|used to validate| API |
| 48 | +
|
| 49 | + JSONSchema -->|used to produce| Meditor |
| 50 | + JSONSchema -->|used to validate| Meditor |
| 51 | + Meditor -->|submits metadata| API |
| 52 | +
|
| 53 | + CLI -->|used to upload & submit metadata| API |
| 54 | +
|
| 55 | + API <-->|metadata JSON| Storage |
| 56 | +
|
| 57 | + %% styling |
| 58 | + classDef repo fill:#f9f9f9,stroke:#333,stroke-width:1px; |
| 59 | + classDef code fill:#e1f5fe,stroke:#0277bd,stroke-width:1px; |
| 60 | + classDef ui fill:#e8f5e9,stroke:#2e7d32,stroke-width:1px; |
| 61 | + classDef data fill:#fff3e0,stroke:#e65100,stroke-width:1px; |
| 62 | + JSONSchema@{ shape: docs } |
| 63 | +
|
| 64 | + class dandi_schema_repo,schema_repo,dandi_cli_repo,dandi_archive_repo repo; |
| 65 | + class Pydantic,CLI,API code; |
| 66 | + class JSONSchema,Storage data; |
| 67 | + class Meditor ui; |
| 68 | +``` |
| 69 | +> The diagram above depicts how metadata models are defined, represented, and used in the DANDI ecosystem before version 0.12.0 of dandi-schema. |
| 70 | +
|
| 71 | +## Solution to Overcome Limitations |
| 72 | + |
| 73 | +The solution of vendor-configurable metadata model addresses the limitations outlined above by implementing the following changes: |
| 74 | + |
| 75 | +1. Make the metadata models vendor-configurable in dandi-schema. |
| 76 | +2. Create an API endpoint at `/api/schemas/` in dandi-archive to distribute dynamically generated JSON Schema representations of the metadata models |
| 77 | + from the Pydantic models that define the metadata models at runtime. |
| 78 | +3. Update the `/api/info/` endpoint at dandi-archive |
| 79 | + 1. to point to the endpoint in point 2 for retrieving a JSON Schema representation of the metadata models |
| 80 | + instead of a static versioned JSON Schema representation stored at [dandi/schema](https://github.com/dandi/schema). |
| 81 | + 2. to include vendor-specific information. |
| 82 | +4. Remove any hardcoded vendor-specific information in dandi-archive, and use the vendor-specific configuration |
| 83 | + provided by dandi-schema. |
| 84 | +5. Have clients, such as the web UI (meditor), use the endpoints in point 2 and 3 to retrieve vendor-specific configurations |
| 85 | + and JSON Schema representations of the metadata models that match the metadata models used by the particular instance of dandi-archive. |
| 86 | + |
| 87 | + |
| 88 | +```mermaid |
| 89 | +flowchart TD |
| 90 | + %% repositories as grouped nodes |
| 91 | + subgraph dandi_schema_repo["<a href='https://github.com/dandi/dandi-schema/'>dandi/dandi-schema</a>"] |
| 92 | + Pydantic["Pydantic Models"] |
| 93 | + end |
| 94 | +
|
| 95 | + subgraph schema_repo["<a href='https://github.com/dandi/schema/'>dandi/schema</a>"] |
| 96 | + JSONSchema["JSON Schema<br>serializations"] |
| 97 | +
|
| 98 | + end |
| 99 | +
|
| 100 | + subgraph dandi_archive_repo["<a href='https://github.com/dandi/dandi-archive/'>dandi-archive</a>"] |
| 101 | + Meditor["Web UI<br/>Metadata Editor<br/>(meditor; Vue)"] |
| 102 | + API["Archive API<br/>(Python; DJANGO)"] |
| 103 | + SchemaEndpoint["Schema API Endpoint<br/>(JSONSchema)"] |
| 104 | + Storage[("DB (Postgresql)")] |
| 105 | + end |
| 106 | +
|
| 107 | + subgraph dandi_cli_repo["<a href='https://github.com/dandi/dandi-cli'>dandi-cli</a>"] |
| 108 | + CLI["CLI & Library<br>validation logic<br/>(Python)"] |
| 109 | + end |
| 110 | +
|
| 111 | + %% main flow |
| 112 | + Pydantic -->|"serialize into<br/>(CI)"| JSONSchema |
| 113 | + Pydantic -->|used to validate| CLI |
| 114 | + Pydantic -->|used to validate| API |
| 115 | +
|
| 116 | + API -->|serialize at runtime| SchemaEndpoint |
| 117 | + SchemaEndpoint -->|used to produce| Meditor |
| 118 | + SchemaEndpoint -->|used to validate| Meditor |
| 119 | +
|
| 120 | + Meditor -->|submits metadata| API |
| 121 | + CLI -->|used to upload & submit metadata| API |
| 122 | + API <-->|metadata JSON| Storage |
| 123 | +
|
| 124 | + %% styling |
| 125 | + classDef repo fill:#f9f9f9,stroke:#333,stroke-width:1px; |
| 126 | + classDef code fill:#e1f5fe,stroke:#0277bd,stroke-width:1px; |
| 127 | + classDef ui fill:#e8f5e9,stroke:#2e7d32,stroke-width:1px; |
| 128 | + classDef data fill:#fff3e0,stroke:#e65100,stroke-width:1px; |
| 129 | + JSONSchema@{ shape: docs } |
| 130 | +
|
| 131 | + class dandi_schema_repo,dandi_cli_repo,dandi_archive_repo repo; |
| 132 | + class Pydantic,CLI,API,SchemaEndpoint code; |
| 133 | + class JSONSchema,Storage data; |
| 134 | + class Meditor ui; |
| 135 | +``` |
| 136 | +> The diagram above depicts how metadata models are defined, represented, and used in the DANDI ecosystem starting with version 0.12.0 of dandi-schema. |
| 137 | +
|
| 138 | + |
| 139 | +### Benefits |
| 140 | + |
| 141 | +This implementation provides several benefits: |
| 142 | + |
| 143 | +1. **Runtime Consistency**: The schema used by the frontend will always match the one used by the backend, including any vendor-specific configurations. |
| 144 | +2. **Simplified Deployment**: No need to manually update JSON Schema files or manage the [dandi-schema](https://github.com/dandi/dandi-schema) repository for storing |
| 145 | + JSON Schema representations of the metadata models. |
| 146 | +3. **Future-Proofing**: The implementation allows for future support of multiple schema versions if needed. |
| 147 | +4. **Reduced Dependencies**: Removes the dependency on external GitHub URLs for schema definitions. |
| 148 | + |
| 149 | +### Immediate Steps and Longer-Term Opportunities |
| 150 | + |
| 151 | +The immediate implementation supports distributing, through an API endpoint, the JSON Schema representations of only the vendor-configurable metadata models currently being used |
| 152 | +by the particular instance of dandi-archive. However, the API endpoint has been structured to allow support for multiple versions of JSON Schema representations in the future if needed. |
| 153 | + |
| 154 | +Additionally, the JSON-LD context.json could also be similarly generated and served by the backend if needed in the future. |
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