Kettle jobs and transformations are full of visual indicators to help us easily and quickly understand why and when the flows follow this path, if the task or step is running, whether it's terminating successfully or not, or other such similar things. Taking care of these indications helps us a lot in understanding if everything has gone, or will go, according to what we intended.
Let's see some examples. While designing a transformation in Spoon, you can see that the connections between the steps (called hops) assume different colors or representation in different situations. The following screenshot shows a Data Validator step with a set of inputs and two outputs:
We can note two interesting things here:
We can summarize the meaning behind the various hop colors as shown in the following table:
Color |
Meaning |
---|---|
Green |
The hop distributes rows; if multiple hops are leaving a step, rows of data will be distributed evenly to all the target steps |
Red |
The hop copies rows; if multiple hops are leaving a step, all rows of data will be copied to all the target steps |
Yellow |
The hop provides information for the step and distributes rows |
Gray |
The hop is disabled |
Black |
The hop has a named target step |
Blue |
Candidate hop using middle button and drag |
Red (bold dotted line) |
The hop is used for carrying rows that caused errors in the source step(s) |
Other kinds of icons can be found while designing transformations in other situations. Let's see another example where a Filter step is going to be used:
As you can see, the Filter step named Filter rows with different countries has two different output hops with two different icons indicated by the two red bold letters A and B:
Similar concepts apply to a job's hops. Let's have a look at the following example:
Because the jobs are process orchestrators in this case, a job hop is just an element of flow control. Hops link to job entries, and based on the results of the previous job entry, they determine what happens next. Icons help us to indicate the conditions under which that particular hop is followed:
Again, hops in jobs assume different colors depending on the properties and the state of the job at that particular point: