PHP-ETL - Cook Books
Split/Fork the chain
In our next example
- One file containing all the customers
- A second file containing unsubscribed customers
- A third file with subscribed customers.
To achieve this we will use the split operation. This operation creates multiple new chains linked to the first chain. The result of these new chains are not attached to the main chain. So if we do any filtering in one of these branches as they are called, the filtering will not be visible on the main branch.
For our example, the main branch will be used to write all customers, this is very similar to what we did in the first example. But before writing the files we will add a split operation to create 2 new branches. 1 branch will filter to get subscribed customers and write them. The second branch will filter to get un subscribed customers and write them.
branch-out:
operation: split
options:
branches:
-
filter-unsubscribed:
operation: filter
options:
rule: [{get : {field: 'IsSubscribed'}}]
negate: false
write-new-file:
operation: csv-write
options:
file: "subscribed.csv"
-
filter-subscribed:
operation: filter
options:
rule: [{get : {field: 'IsSubscribed'}}]
negate: true
write-new-file:
operation: csv-write
options:
file: "unsubscribed.csv"
Complete Code
chain:
read-file:
operation: csv-read
options: [] # The default delimeter,&
branch-out:
operation: split
options:
branches:
-
filter-subscribed:
operation: filter
options:
rule: [{get : {field: 'IsSubscribed'}}]
negate: false
write-new-file:
operation: csv-write
options:
file: "subscribed.csv"
-
filter-unsubscribed:
operation: filter
options:
rule: [{get : {field: 'IsSubscribed'}}]
negate: true
write-new-file:
operation: csv-write
options:
file: "unsubscribed.csv"
write-new-file:
operation: csv-write
options:
file: "output.csv"
flowchart TB
S1[Read CSV] -->|Subscribed| S2{Split Step}
S1 -->|UnSubscribed| S2
S2 -->|Susbscribed| S2A1(Filter Subscribed)
S2 -->|UnSubscribed| S2A1
S2 -->|Susbscribed| S2B1(Filter UnSubscribed)
S2 -->|UnSubscribed| S2B1
subgraph SubFlow
S2A1 -->|Susbscribed| S2A2(Write Subscribed)
S2B1 -->|UnSubscribed| S2B2(Write UnSubscribed)
end
S2 --->|Susbscribed| S3(Write Both)
S2 --->|UnSubscribed| S3