diagrams/docs/node.md

id	title
node	Nodes

Node is a second object representing a node or system component.

Basic

Node is an abstract concept that represents a single system component object.

A node object consists of three parts: provider, resource type and name. You may already have seen each part in the previous example.

from diagrams import Diagram
from diagrams.aws.compute import EC2

with Diagram("Simple Diagram"):
    EC2("web")

In above example, the EC2 is a node of compute resource type which provided by aws provider.

You can use other node objects in a similar manner like:

# aws resources
from diagrams.aws.compute import ECS, Lambda
from diagrams.aws.database import RDS, ElastiCache
from diagrams.aws.network import ELB, Route53, VPC
...

# azure resources
from diagrams.azure.compute import FunctionApps
from diagrams.azure.storage import BlobStorage
...

# gcp resources
from diagrams.gcp.compute import AppEngine, GKE
from diagrams.gcp.ml import AutoML 
...

# k8s resources
from diagrams.k8s.compute import Pod, StatefulSet
from diagrams.k8s.network import Service
from diagrams.k8s.storage import PV, PVC, StorageClass

Data Flow

You can represent data flow by connecting the nodes with these operators: >>, << and -.

• »: Connect nodes in left to right direction.
• «: Connect nodes in right to left direction.
• -: Connect nodes in no direction. Undirected.

from diagrams import Diagram
from diagrams.aws.compute import EC2
from diagrams.aws.database import RDS
from diagrams.aws.network import ELB
from diagrams.aws.storage import S3

with Diagram("Web Services", show=False):
    ELB("lb") >> EC2("web") >> RDS("userdb") >> S3("store")
    ELB("lb") >> EC2("web") >> RDS("userdb") << EC2("stat")
    (ELB("lb") >> EC2("web")) - EC2("web") >> RDS("userdb")

Be careful when using the - and any shift operators together, which could cause unexpected results due to operator precedence.

The order of rendered diagrams is the reverse of the declaration order.

You can change the data flow direction with direction parameter. Default is LR.

(TB, BT, LR and RL) are allowed.

from diagrams import Diagram
from diagrams.aws.compute import EC2
from diagrams.aws.database import RDS
from diagrams.aws.network import ELB

with Diagram("Workers", show=False, direction="TB"):
    lb = ELB("lb")
    db = RDS("events")
    lb >> EC2("worker1") >> db
    lb >> EC2("worker2") >> db
    lb >> EC2("worker3") >> db
    lb >> EC2("worker4") >> db
    lb >> EC2("worker5") >> db

Group Data Flow

Above worker example has too many redundant flows. In this case, you can group nodes into a list so that all nodes are connected to other nodes at once.

from diagrams import Diagram
from diagrams.aws.compute import EC2
from diagrams.aws.database import RDS
from diagrams.aws.network import ELB

with Diagram("Grouped Workers", show=False, direction="TB"):
    ELB("lb") >> [EC2("worker1"),
                  EC2("worker2"),
                  EC2("worker3"),
                  EC2("worker4"),
                  EC2("worker5")] >> RDS("events")

You can’t connect two lists directly because shift/arithmetic operations between lists are not allowed in Python.