repository·master·Indexed 41 days ago
https://github.com/akarneliuk/pygnmiA pure Python implementation of a gNMI client used to interact with network functions via gRPC. It supports standard gNMI RPCs including Capabilities, Get, Set, and Subscribe, and is tested against NOS such as Arista EOS, Nokia SR OS, Cisco IOS XR, Juniper JUNOS, Nokia SRLinux, and Cisco NX-OS. The library provides the gNMIclient class for session management, a telemetryParser for converting Protobuf messages to Python dictionaries, and a pygnmicli command-line tool.
The library supports several path naming conventions, automatically converting them to the canonical format /origin:element1/element2.... Supported formats include:
yang-module:container/container[key=value]/yang-module:container/container[key=value]/yang-module:/container/container[key=value]/container/container[key=value]You can also omit the YANG module name if the vendor implementation requires it: /element1/element2....
For building telemetry collectors, it is highly recommended to use the subscribe2() method instead of the older subscribe() method. subscribe2() is actively developed, thoroughly tested, and supports all telemetry modes (STREAM, ONCE, POLL) by simply providing a corresponding dictionary as input. It also includes automatic use of telemetryParser and proper qos support.
# Example concept: subscribe2() is the preferred method for telemetry
# client.subscribe2(input_dict)To interact with network functions using gNMI, use the gNMIclient class from pygnmi.client. The client is designed to be used as a context manager. You can perform operations like get by providing a list of paths.
Supported RPCs include:
Supported operation modes:
# Modules
from pygnmi.client import gNMIclient
# Variables
host = ('169.254.255.64', '57400')
# Body
if __name__ == '__main__':
with gNMIclient(target=host, username='admin', password='admin', insecure=True) as gc:
result = gc.get(path=['openconfig-interfaces:interfaces', 'openconfig-acl:acl'])
print(result)When working with gNMIclient, consider the following for session management:
with GNMICLient(...) as client: to ensure the session is properly closed.client.close() explicitly.gnmi_timeout key in the gNMIclient constructor.The gNMIclient supports several authentication and security configurations:
token argument: gNMIclient(token=TOKEN).username and password arguments.skip_verify argument to bypass certificate verification. For this to work, the certificate must contain at least one subject alternative name (DNS, IP, etc.).GRPC_SSL_CIPHER_SUITES to HIGH for specific requirements (e.g., Nokia SR OS).# Token-based authentication
client = GNMICLient(target='1.1.1.1', token='YOUR_TOKEN')
# Skip TLS verification
client = GNMICLient(target='1.1.1.1', skip_verify=True)The telemetryParser converts gNMI Protobuf messages into a Python dictionary. The resulting structure typically follows this pattern:
update: A dictionary containing:prefix: The resource path string (e.g., /interfaces/interface[name=eth0]).timestamp: The timestamp of the update.update: A list of individual path/value updates.path: The specific path to the value.val: The actual value (parsed into Python types like int, str, dict for JSON, etc.).delete: (Optional) A list of paths that were deleted.sync_response: (Optional) Metadata indicating the end of a synchronization period.The encoding parameter can be specified in get(), set(), and subscribe2() methods.
If encoding is not explicitly provided by the user, pygnmi automatically detects supported encodings by calling capabilities() during the connect() phase. It prioritizes json first, followed by json_ietf.
pyGNMI supports the following standard gNMI RPC operations:
CapabilitiesGetSetSubscribepyGNMI has been tested against the following Network Operating Systems:
Broadcom SONiC is currently in testing.
The pygnmicli tool allows interacting with gNMI devices via the CLI. Key features include:
-e or --encoding to specify the encoding (overrides default).--token for token-based authentication.--history flag.--no-qos-marking flag.prefix to commands.The gNMIclient class is the primary interface for interacting with network devices via gNMI. You can initialize it with connection details such as target, credentials, and security settings.
Key Parameters:
target: A tuple (host, port) or a string for Unix domain sockets.username / password: Credentials for authentication.insecure: Set to True to use an insecure gRPC channel.path_cert, path_key, path_root: Paths to SSL/TLS certificates for secure connections.skip_verify: If True, the client attempts to automatically resolve certificate mismatches by extracting Common Names (CN) or Subject Alternative Names (SANs) from the device certificate.gnmi_timeout: Connection timeout in seconds.token: An optional access token for bearer authentication.from pygnmi.client import gNMIclient
client = gNMIclient(
target=('192.168.1.1', 50051),
username='admin',
password='password',
path_cert='client.crt',
path_key='client.key',
path_root='ca.crt'
)If you encounter transient failures (specifically StatusCode.FAILED_PRECONDITION, often due to lock contention or system startup), use set_with_retry(). This method attempts the set() operation once, and if it fails with the specified error, it waits for a retry_delay (default 3s) and tries one more time.
# Retries once after a FAILED_PRECONDITION error
client.set_with_retry(update=my_updates, retry_delay=5)