canonical: https://jentic.com/apis/azure.com/datalakestorefilesystemmanagementclient

# Microsoft Azure DataLakeStoreFileSystemManagementClient

Jentic publishes the only available OpenAPI specification for DataLakeStoreFileSystemManagementClient, keeping it validated and agent-ready. The API exposes the WebHDFS-compatible filesystem layer of an Azure Data Lake Store Gen1 account, focused on the extensions that matter for agent workflows: concurrent append, file expiry, and access checks. It is reached at the per-account endpoint and complements the standard WebHDFS verbs published by the underlying service.

## For AI agents

Append data concurrently, set file expiry, and check access on files in an Azure Data Lake Store Gen1 account using its WebHDFS-compatible endpoint.

## Scope

Does not provision Data Lake Store accounts, manage U-SQL jobs, or run analytics queries - use for the WebHDFS extension operations on a Data Lake Store Gen1 account only.

## Capabilities

- Append data to a Data Lake Store file using the concurrent append extension
- Set or clear an expiry time on a file in Data Lake Store
- Check whether the caller has a given access permission on a file path
- Reach the WebHDFS-compatible endpoint of a Data Lake Store Gen1 account
- Use Data Lake Store extensions that go beyond standard WebHDFS verbs

## Use cases

### Concurrent ingestion to a Data Lake file

Multiple writers (a fleet of edge nodes or a parallel ingestion pipeline) need to append events to the same Data Lake Store file without coordinating writes. The concurrent append endpoint accepts batches from each writer and orders them server-side, so an ingestion controller can drive parallel writes safely.

Example prompt: Append a 4 KB batch of newline-delimited JSON events to '/raw/events-2026-06-10.jsonl' in the target Data Lake Store account using the ConcurrentAppend extension

### Time-bound scratch files

Pipelines often write intermediate scratch files that should be cleaned up automatically. The file expiry endpoint lets the pipeline stamp a deletion time on a file at write time so the lake garbage-collects the artefact without an explicit delete step.

Example prompt: Set the expiry on '/scratch/job-1234/output.tsv' to 24 hours from now using the SetFileExpiry endpoint

### Pre-flight access check

Before submitting a long-running U-SQL job that reads a list of paths, the controller verifies the calling identity has the required permission on each path. The CheckAccess endpoint reports whether the caller has the requested access mode on a path so the job is rejected early instead of failing mid-run.

Example prompt: Call CheckAccess on '/protected/finance' with mode 'r--' and confirm the current identity has read permission

### Agent-driven safe write

An AI agent loading data into a partner's Data Lake Store first checks read access on the target folder, then concurrently appends the payload into a daily file, then stamps an expiry to enforce retention. Through Jentic, the agent chains these three operations using the same scoped credential without leaving the SDK.

Example prompt: Verify read access on '/inbound/partner-x', concurrently append the supplied payload to today's partner-x file, and set a 30-day expiry

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| POST | /WebHdfsExt/{path} | Concurrent append to a Data Lake Store file |
| PUT | /WebHdfsExt/{path} | Set the file expiry on a path |
| GET | /webhdfs/v1/{path} | Check access on a Data Lake Store path |

## Key resources

- **ConcurrentAppend** — Append data to a file from multiple writers without coordinating offsets
- **SetFileExpiry** — Set or clear an expiry time on a Data Lake Store file
- **CheckAccess** — Check whether the caller has the requested access mode on a path

## Why Jentic

- **Setup:** Wiring the Azure Data Lake Store filesystem layer by hand means resolving the per-account host from the {accountName}.{adlsFileSystemDnsSuffix} template, obtaining an Azure AD bearer token for the Data Lake Store resource, and setting the correct WebHDFS op flag on every request yourself. Through Jentic you install once, import Data Lake Store FileSystem Management from the API Directory, store the Azure credential once, and your agent calls it.
- **Permission scoping:** The filesystem API puts the file path in the URL (/WebHdfsExt/{path} and /webhdfs/v1/{path}), so a rule can pin your agent to specific path prefixes. You choose the operations it may call, so limit the agent to the ones it needs, such as ConcurrentAppend or CheckAccess, rather than adding the SetFileExpiry write when it only reads.
- **Credential handling:** Your Azure credential is stored once, encrypted, by your own Jentic One instance and injected as a scoped bearer token at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'concurrently append to a Data Lake Store file' or 'check access on a lake path', and Jentic returns the matching WebHDFS extension operation with its path parameter and required op flag so the agent calls it correctly.

## Related APIs

- **DataLakeStoreAccountManagementClient** — Manages the Data Lake Store account itself rather than its files
- **DataLakeAnalyticsCatalogManagementClient** — Browses U-SQL catalog metadata over Data Lake Store data
- **DataShareManagementClient** — Shares datasets across Azure subscriptions instead of writing to lake files

## FAQ

### Why is there no official OpenAPI spec for DataLakeStoreFileSystemManagementClient?

Microsoft Azure does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call DataLakeStoreFileSystemManagementClient via structured tooling. It is validated against the live API and kept up to date. Get started with Jentic One, the self-hosted execution layer.

### What authentication does the Data Lake Store Filesystem API use?

The Data Lake Store Gen1 filesystem endpoint is gated by Azure Active Directory bearer tokens issued for the Data Lake Store resource. Through Jentic, the AAD credential is held in the encrypted vault and a scoped token is supplied at execute time so the bearer token never appears in the agent's context.

### Can I append data to a single file from multiple writers with this API?

Yes. POST /WebHdfsExt/{path} with op=CONCURRENTAPPEND accepts payloads from concurrent writers and orders them server-side. This is the recommended pattern for parallel ingestion into a single Data Lake Store file without coordinating offsets between writers.

### What are the rate limits for the Data Lake Store Filesystem API?

Data Lake Store Gen1 throttles by ingress and egress throughput per account rather than by request count, and returns 503 with a Retry-After hint when an account exceeds its provisioned throughput. Size individual append payloads to the documented 4 MB chunk limit and back off on 503 responses.

### How do I set an expiry on a Data Lake Store file through Jentic?

Search Jentic for 'set file expiry data lake store', load the schema for PUT /WebHdfsExt/{path} with op=SETEXPIRY, then execute with expiryOption=Absolute or RelativeToNow and the desired expireTime. The pip install jentic Python SDK uses the async search, load, execute pattern.

### Is the Data Lake Store Filesystem API free?

There is no per-request charge for the filesystem extension calls themselves; you pay for storage and transactions in Data Lake Store Gen1 according to the standard Azure pricing for the service. Note that Gen1 has been retired in favour of ADLS Gen2 - new workloads should target Gen2 with its blob-compatible API.

### Can I limit what my agent is allowed to do with the Data Lake Store Filesystem API?

Yes. Because you run Jentic One yourself, your own rules decide which operations and credentials the agent may use, and this API puts the file path directly in the URL (/WebHdfsExt/{path} and /webhdfs/v1/{path}), so you can pin the agent to specific path prefixes. You also choose which operations it may call, so you can allow only ConcurrentAppend or CheckAccess and withhold the SetFileExpiry write when the agent only needs to read or append. The Azure credential is injected as a scoped bearer token at execution time and never enters the agent's prompt or logs.