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How to query metadata via the Neptune API#

With the Neptune API, you can query and fetch your logged metadata to the local machine.

You can download metadata logged in your project in bulk, or extract data from individual objects.

This page outlines some common ways to access typical metadata. For the full list of ways to interact with metadata fields, see Field types reference.

Downloading runs table as DataFrame#

To download the runs table of a project as a pandas DataFrame, initialize the project with init_project() and use the fetch_runs_table() method:

import neptune

project = neptune.init_project(
    project="workspace-name/project-name", # (1)!

# Get dashboard with runs contributed by "jackie" and tagged "cycleLR"
runs_table_df = project.fetch_runs_table(owner="sophia", tag="cycleLR").to_pandas()

  1. The full project name. For example, "ml-team/classification".

    To copy it, navigate to the project settings in the top-right () and select Edit project details.


The same applies to models stored in the model registry. Fetch them with fetch_models_table()

The returned runs_table_df is a pandas DataFrame, where

  • each row represents a run.
  • each column represents a metadata field, such as metrics, text logs, and parameters.

To include only certain fields as columns in the table, you can specify the names of namespaces or fields with the columns parameter:

# Fetch table of runs, including only the "f1_score" and "sys/running_time"
# fields as columns
>>> filtered_runs_table = project.fetch_runs_table(
...     columns=["f1_score", "sys/running_time"]
... )
>>> filtered_runs_df = filtered_runs_table.to_pandas()
>>> print(filtered_runs_df)
    sys/id  sys/running_time  f1_score
0    CLS-8             5.436      0.95
1    CLS-7            12.342      0.92
2    CLS-6           318.538      0.80
3    CLS-5             9.560      0.80


Querying metadata from object#

To query metadata from a given run or other object, you fetch or download the metadata in a similar fashion as you logged it.

The methods correspond in the following way:

Logging method Querying method Field type to use on
= or assign() fetch() Any single value field except (File)
add() fetch() Tags (StringSet)
append() (prev. log()) fetch_last(), fetch_values() FloatSeries, StringSeries
append(File()) download_last(), download() FileSeries
track_files() fetch_hash(), fetch_files_list(), download() Artifact
upload(), upload_files() download() File, FileSet

For the full list, see API referenceField types.

Initializing existing object#

Start by initializing Neptune with the ID of the object:

import neptune

run = neptune.init_run(with_id="CLS-8", mode="read-only")
How do I find the ID?

The Neptune ID is a unique identifier for the object. In the table view, it's displayed in the leftmost column.

The ID is stored in the system namespace (sys/id). If the object is active, you can obtain its ID with neptune_object["sys/id"].fetch(). For example:

>>> run = neptune.init_run(project="ml-team/classification")
>>> run["sys/id"].fetch()

Setting the mode to "read only" ensures that no data is added or changed.

Querying single value#

Use the fetch() method to query any single-valued metadata of the object:

params = run["parameters"].fetch()
batch_size = run["parameters/batch_size"].fetch()
f1_score = run["f1_score"].fetch()

The same method works for fields in the system namespace:

username = run["sys/owner"].fetch()  # string
last_updated = run["sys/modification_time"].fetch()  # datetime
my_run_id = run["sys/id"].fetch()  # run ID

Fetching artifact metadata#

See Download artifact metadata.

Querying tags#

You can access the tags of an object by using fetch() on the sys/tags field:

run_tags = run["sys/tags"].fetch()

if "exploration" in run_tags:

Querying values from series field#

For value series logged with the append() (previously log()) method, you can query either the last value or the full list of values.

# Accessing last value of FloatSeries
final_loss = run["train/loss"].fetch_last()

# Accessing last value of StringSeries
last_stderr_line = run["monitoring/6519428b/stderr"].fetch_last()

Retrieve all the values and their indexes as a pandas DataFrame with fetch_values():

loss_df = run["train/loss"].fetch_values()

# Don't include timestamp
loss_df = run["train/loss"].fetch_values(include_timestamp=False)

Similarly, from FileSeries fields, you can download the last file to the disk with download_last() or download all files with download():

# Download last file in the FileSeries

# Download all files in the FileSeries

Downloading files#

Use download() to query uploaded files:

# Download example_image to the current directory

# Download model to the specified directory

You can also download files from artifact fields:

# Download all files from the artifact, optionally specifying a download destination

For details, see Download artifact metadata.

Query nested namespaces or fields#

To query namespaces or fields that are nested under another namespace, you can access the object structure with get_structure().


To get the monitoring sub-namespaces, which are generated automatically by Neptune for each process: