After using Nifi for some weeks now, I have an enhancement request to recommend for the UI that I believe will dramatically improve the usability.
Before I jump into the problems, let me say this about the UI. It's very intuitive, easy to learn and consistent. It's also very clean and attractive from an appearance standpoint. As described below, there are some areas that are becoming tedious with dozens of processors today, and that will become acute from a usability perspective if untreated. The Challenges Issue #1 - Processors take too much time to select and configure initially Overall, the Nifi UI is fantastic from an ease of use perspective; however, there is one area that's problematic and that will become increasingly challenging... adding new processor blocks and choosing the processor type. The primary issue stems from the lengthy list of processors to scroll through and pick from. The filter cloud is helpful, but with time even this mechanism is reaching its limits, as the number of processors continues to grow with the success of the project. There needs to be an easier, more productive way to simply drag and drop processors to the canvass. Issue #2 - Processor blocks all look the same instead of being more visually distinct and easily recognizable by function Our brains are wired for rapid pattern recognition of images, text takes more cycle of higher-level reasoning to interpret. Because processor blocks are shown, by default, with their I/O statistics and textual names, they all kind of look the same. This "runtime view" is great for troubleshooting or monitoring, but not as useful when building complex data flows. An "iconic view" would provide an easier way to visualize the structure and intent behind each graph and its flows, especially when developing the flows. Additionally, an icon representing each type of processor block would make it much faster and easier to recognize what that processor block does, versus having to read and interpret each one individually (especially for complex graphs). Processors that handle files could be represented by a "file" icon, Hadoop by a Hadoop icon, HTTP by a globe icon, etc. #3 - When dropping a new processor, open its Properties dialog automatically (to avoid right-click, then "Configure" and choose tab steps) Every time a new processor is dropped onto the canvass, we must go through the process to select its type. Then, the dialog closes and we're usually left with an incomplete processor with errors. We know that most processors require some initial Property configuration, so why not just proceed to that dialog after choosing the processor type, so can finish configuring it, then apply so we have a processor that's ready to integrate? Potential Solutions Visio has a great model for addressing #1 that I would propose as a starting point for resolving this issue - use of a "tool palette" that snaps into place on the left side of the canvass. Each group of tools (e.g., file-related processors, Hadoop processors, HTTP processors, etc.) would be grouped together within a toolbox area, with an icon representing each tool/processor with a brief description of each tool. As with Visio, the user would open up several commonly used toolboxes and then just drag and drop a tool from the toolbox directly onto the canvass, with no need to select the processor type (each processor is shown as a unique type in its toolbox). This approach is very familiar to Visio users and other tools that operate in a similar manner with object drag and drop. Scrolling through lengthy lists is time-consuming and becomes tedious when developing large graphs. Once processors have icons associated with them, several things become much easier: 1. The toolboxes are much easier to create, leveraging each processors inherent icon representation 2. The runtime view (current view) could simply have each processor's icon shown (either in the white space to left of "5 mins" or in the border area) 3. If a purely iconic view were added at some future point, then a clear "as built" drawing of the data flow would make the graphs even more self-documenting and obvious Lastly, when the generic processor is dragged onto the canvass (as it is today), and a processor type is selected, it would be very easy to proceed next to the Property dialog (if there are any mandatory properties that must be configured before first use), reducing the number of clicks required to get a processor up and running. I believe a usability study with target users would likely reveal the above (or similar) conclusions. In order for Nifi to scale with dozens or even hundreds more processors, it's clear that something has to give, as the current method of choosing processor type has about run its course from a usability standpoint IMHO. Hope that's helpful. Rick
