# README

DP Files API

Introduction

The Files API is part of the Static Files System. This API is responsible for storing the metadata and state of files.

It is used by the Upload Service to store the metadata of the file being uploaded and keep track of the state of the file during uploaded. During upload the state will be CREATED. Once the full file have been uploaded the upload service should inform this API the upload is complete and the files state will be moved to UPLOADED.

Any service interesting in the metadata or the state of a file can just the GET endpoints. A single files metadata can be retrieved by its path or all files in a collection can be retrieved by ID.

The Download Service uses this API to see whether a file exists and what state it is in before attempting to serve the file to consumers wishing to access the file.

The API has two end points to publish files. Files can be individually published by PATCHING the state to be PUBLISHED. It is also to publish all files in a collection in one call by PATCHING /collection/{collection_id}, this can be used to reduce the number of API calls required to publish a large collection. Currently, most calls to a publish file will come from the Zebedee Publisher

When a file is published this API sends a message via Kafka to the Static File Publisher that permanently moves the file and inform this API that the file is now moved via an HTTP call.

REST API

The api is fully documented in Swagger Docs

Note: When using PATCH calls to modify the file metadata you can either send a collection_id to set the collection_id on a file where it is not already sent or change the state of a file.

Metadata

Field	Notes
path	The identifier of a file that is stored. Globally unique, and forms part of the bucket/object name when stored
is_publishable	This field currently is ignored and has no affect, the file will be published if a publish update is sent!
collection_id	Optional during upload, must be set for the file to be published
title	Optional
size_in_bytes	The size of the file
type	mimetype of the file, e.g. "text/csv", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
licence	Freetext name of the licence under which the file is made available
licence_url	URL to the license
state	State of the file - CREATED, UPLOADED, PUBLISHED, MOVED
etag	Cyrptographic hash of the file content

Additional Metadata

Additional timestamp data about the file is stored in the database but not exposed via the API. Those fields are:

Field
created_at
last_modified
upload_completed_at
published_at
moved_at

File States

State	Description
CREATED	File upload has started and the metadata has been provide to this API
UPLOADED	File upload has been completed. The etag for the final file has been provided
PUBLISHED	The file has been published (it is available to the public, but is not yet permently moved)
MOVED	The file has been permanently moved and moved to the public bucket for storage. The public files etag has been provided



 Start     ┌──────────────┐ File      ┌──────────────┐ File       ┌───────────────┐ File       ┌───────────────┐
 Upload    │              │ Uploaded  │              │ Published  │               │ Moved      │               │
      ────►│   CREATED    ├──────────►│   UPLOADED   ├───────────►│   PUBLISHED   ├───────────►│     MOVED     │
           │              │           │              │            │               │            │               │
           └──────────────┘           └──────────────┘            └───────────────┘            └───────────────┘
             File is in a               File is ready               File is available           File is available
             unusable                   for review &                for public download         for public download
             state                      approval                    The stored version          directly from S3
             Can resume upoad           Can be pre-viewed           is moved on-demand          where it is stored

Getting started

Run make debug

Dependencies

No further dependencies other than those defined in go.mod

Configuration

Environment variable	Default	Description
BIND_ADDR	:26900	The host and port to bind to
GRACEFUL_SHUTDOWN_TIMEOUT	5s	The graceful shutdown timeout in seconds (`time.Duration` format)
HEALTHCHECK_INTERVAL	30s	Time between self-healthchecks (`time.Duration` format)
HEALTHCHECK_CRITICAL_TIMEOUT	90s	Time to wait until an unhealthy dependent propagates its state to make this app unhealthy (`time.Duration` format)
IS_PUBLISHING	false	Whether the service is running in the Publishing domain
PERMISSIONS_API_URL	http://localhost:25400	The hostname of the permissions API
IDENTITY_API_URL	http://localhost:25600	The hostname of the identity API
ZEBEDEE_URL	http://localhost:8082	The hostname of the zebedee API
KAFKA_ADDR	`kafka:9092`	A (comma delimited) list of kafka brokers (TLS-ready)
KAFKA_VERSION	`2.6.1`	The version of (TLS-ready) Kafka being used
KAFKA_MAX_BYTES	`200000`	The max message size for kafka producer
KAFKA_SEC_PROTO	unset	if set to `TLS`, kafka connections will use TLS ([ref-1])
KAFKA_SEC_CLIENT_KEY	unset	PEM for the client key ([ref-1])
KAFKA_SEC_CLIENT_CERT	unset	PEM for the client certificate ([ref-1])
KAFKA_SEC_CA_CERTS	unset	CA cert chain for the server cert ([ref-1])
KAFKA_SEC_SKIP_VERIFY	false	ignores server certificate issues if `true` ([ref-1])
STATIC_FILE_PUBLISHED_TOPIC	static-file-published-v2
MONGODB_BIND_ADDR	`localhost:27017`	Address of MongoDB
MONGODB_DATABASE	`files`	The mongodb database to store imports
MONGODB_COLLECTIONS	`metadata`	The (comma delimited) list of mongodb collections to store imports
MONGODB_USERNAME	unset	The mongodb username
MONGODB_PASSWORD	unset	The mongodb username
MONGODB_ENABLE_READ_CONCERN	false	Switch to use (or not) majority read concern
MONGODB_ENABLE_WRITE_CONCERN	true	Switch to use (or not) majority write concern
MONGODB_CONNECT_TIMEOUT	5s	The default timeout when connecting to mongodb
MONGODB_QUERY_TIMEOUT	15s	The default timeout for querying mongodb
MONGODB_IS_SSL	false	Switch to use (or not) TLS when connecting to mongodb
MONGODB_VERIFY_CERT
MONGODB_CERT_CHAIN
MONGODB_REAL_HOSTNAME