My users want to store my app's settings in a version control system.
(The app targets developers and designers, and allows per-folder settings. Users often ask me to store those settings inside the folder itself, so that they can commit them to VCS.)
The settings are modified from the app's UI and are thus saved programmatically, but I want the resulting file to be human-readable. My first choice would be a pretty-printed JSON, except that it's a funny thing to merge (think those forbidden trailing commas).
That got me thinking: what is the most diff/merge-friendy human-readable text format I can possibly use?
I know many version control systems support external merge tools, but I don't want to burden the users with additional setup. My goal is to minimize accidental conflicts while keeping a reasonable, readable format and without any additional effort from the user.
The data I store is basically a list of rules, and each rule has a number of user-configurable properties. Like this:
rules:
- type: compile
source: *.less
destination: *.css
compiler: LESS 1.x
- type: compile
source: *.coffee
destination: *.js
compiler: CoffeeScript 1.3
sourceMaps: true
A line-based YAML looks like a reasonably good choice. An OpenSSH-style config format may work even better.
So two questions:
Has someone tried to solve this problem before and maybe did a write up of their experience?
Anything off the top of your head that I should consider when formatting the output file?
E.g. will it help to add 2-3 empty lines between the rules to defeat the diff context and minimize conflicts in case two users both add a new rule at the end (a pretty typical case)?
Related
In the Snakemake documentation, the includes directive can incorporate all of the rules of another workflow into the main workflow and apparently can show up in snakemake --dag -n | dot -Tsvg > dag.svg. Sub-workflows, on the other hand, can be executed prior to the main workflow should you develop rules which depend on their output.
My question is: how are these two really different? Right now, I am working on a workflow, and it seems like I can get by on just using includes and putting the name of the output in rule all of the main workflow. I could probably even place the output in the input of a main-workflow rule, making the includes workflow execute prior to that rule. Additionally, I can't visualize a DAG which includes the sub-workflow, for whatever reason. What do sub-workflows offer that the includes directive can't do?
The include doesn't "incorporate another workflow". It just adds the rules from another file, like if you add them with copy/paste (with a minor difference that include doesn't affect your target rule). The subworkflow has an isolated set of rules that work together to produce the final target file of this subworkflow. So it is well structured and isolated from both main workflow and other subworkflows.
Anyway, my personal experience shows that there are some bugs in Snakemake that make using subworkflows quite difficult. Including the file is pretty straightforward and easy.
I've never used subworkflows, but here's a case where it may be more convenient to use them rather than the include directives. (In theory, I think you don't need include and subworkflow as you could write everything in a massive Snakefile, the point is more about convenience.)
Imagine you are writing a workflow that depends on result files from a published work (or from a previous project of yours). The authors did not make public the files you need but they provide a snakemake workflow to produce them. Their snakemake workflow may be quite complex and the files you need may be just intermediate steps. So instead of making sense of the all workflow and parsing it into your own include directives, you use subworkflow to generate the required file(s). E.g.:
subworkflow jones_etal:
workdir:
"./jones_etal"
snakefile:
"./jones_etal/Snakefile"
rule all:
input:
'my_results.txt',
rule one:
input:
jones_etal('from_jones.txt'),
output:
'my_results.txt',
...
What does this file hold and how important is it to keep it "correct"?
I've seen people write scripts to just merge any change dealing with it and I've heard others merging it manually every time.
What is the correct way to handle it and why?
The project.pbxproj contains all of the metadata about your project that Xcode uses to build it; the settings, the file references, configuration, targeted platforms, etc...
I.e. it is a critically important.
There really isn't a great answer for this. Typically, teams will avoid conflict by limiting edits to the project to one team member at a time.
The Xcode team has put a lot of effort into making the file merge-friendly. In managing several large projects via svn, I've generally found that the merges are automatic and painless.
Until they aren't. And when they aren't, revert, merge changes by hand (i.e. make the changes in the project that conflicted), and move on.
Try my script xUnique.
What it does:
convert project.pbxproj to JSON format
Iterate all objects in JSON and give every UUID an absolute path, and create a new UUID using MD5 hex digest of the path
All elements in this json object is actually connected as a tree
We give a path attribute to every node of the tree using its unique attribute; this path is the absolute path to the root node,
Apply MD5 hex digest to the path for the node
Replace all old UUIDs with the MD5 hex digest and also remove unused UUIDs that are not in the current node tree and UUIDs in wrong format
Sort the project file inlcuding children, files, PBXFileReference and PBXBuildFile list and remove all duplicated entries in these lists
see sort_pbxproj method in xUnique.py if you want to know the implementation;
It's ported from my modified sort-Xcode-project-file, with some differences in ordering PBXFileReference and PBXBuildFile
With different options, you can use xUnique with more flexibility
Can anyone share his experience on workflow for R peject development under ESS? I tried several times to learn emacs but I have not get it yet. I can understand ESS as an editor, but is there a project view in ESS? what's the efficient ways to set up/view R project directory, coding, and testing, and how's ESS has an edge to facilitate the whole process?
Do you use ESS as a good R editor only or tend to emulate a R IDE environment within ESS?
Thanks for any advices.
It sounds like you're asking two separate questions.
One question concerns workflow and the other concerns using ESS.
As I use StatET and Eclipse, I'll just share my experience regarding the workflow aspect of your question.
As with Vincent I also follow something like the workflow set out by Josh Reich here (also see Hadley's useful comments):
Workflow for statistical analysis and report writing
Although it can vary between projects, I tend to have a couple of main R files
import.R: this imports data files and does any necessary cleaning and manipulation
analyse.R: This generates the output that I need for any final report
main.R: This calls import.R and analyse.R
The aim is for import.R and analyse.R to represent the complete and final workflow for producing the final results of any analyses.
In terms of a directory structure for an analysis project, I'll often also have the following folders
data: for storing any raw data files
meta: for storing meta data, such as variable labels, scoring systems for tests, recoding information, etc.
output: for storing any graphics, tables, or text generated by my analyses that I might want to incorporate into an external program
temp: When exploring the data and brainstorming analyses, I like to type code into files instead of using the console. I tend to label these temp1.R, temp2.R, temp3.R. I store these in a temp folder. That way I have a permanent record that's easily accessible. If the analyses become final they get incorporated into one of the main R files (i.e., import.R or analysis.R)
functions: If I think that a function will be needed across a couple of projects, I often place it one function per file or a set of related functions in a file in a folder called functions. This makes it relatively easy to reuse functions across projects, when the formal requirements of package development are more than needed.
library: If I want to create some general functions that I think will be project specific, I'll place them in this folder
save: A folder to store any saved R objects
StatET and Eclipse make it easy to interact with such a file system.
Of course, given all the R gurus that use ESS and Emacs, I'm sure it also handles interactions with the file system well.
I'm not exactly sure what you expect as an answer on this one. I, for one, have stolen (and adapted) a system that was suggested here a little while ago (by Josh Reich):
Create a folder for every project, and split up your work in a bunch of different .R files:
Load.R for getting your raw data into R;
Prep.R for cleaning the data, recoding variables, etc.;
Func.R for coding any custom functions you will need for evaluation; and
Eval.R for running your final stuff.
If that doesn't fit your style, just change it.
Then, you can either have a master file to call each of the parts one after each other (good for reproducibility), or save at different stages and have the individual scripts load the appropriate data (good if some of the prep work is very computationally/time intensive).
**
On a different note, the trick that is posted at the link really helped me get into ESS. It turns Shift-Enter into a one-stop-ESS-shop: http://www.kieranhealy.org/blog/archives/2009/10/12/make-shift-enter-do-a-lot-in-ess/
Others have given you some good ideas about how to setup your directory/file structure for a project.
You also asked about "project views," in which case you might want to look into the Emacs Code Browser (ECB).
You can find some screen shots of it in action on its site, here:
http://ecb.sourceforge.net/screenshots/index.html
Problem
Your organization has many separate applications, some of which interact with each other (to form "systems"). You need to deploy these applications to separate environments to facilitate staged testing (for example, DEV, QA, UAT, PROD). A given application needs to be configured slightly differently in each environment (each environment has a separate database, for example). You want this re-configuration to be handled by some sort of automated mechanism so that your release managers don't have to manually configure each application every time it is deployed to a different environment.
Desired Features
I would like to design an organization-wide configuration solution with the following properties (ideally):
Supports "one click" deployments (only the environment needs to be specified, and no manual re-configuration during/after deployment should be necessary).
There should be a single "system of record" where a shared environment-dependent property is specified (such as a database connection string that is shared by many applications).
Supports re-configuration of deployed applications (in the event that an environment-specific property needs to change), ideally without requiring a re-deployment of the application.
Allows an application to be run on the same machine, but in different environments (run a PROD instance and a DEV instance simultaneously).
Possible Solutions
I see two basic directions in which a solution could go:
Make all applications "environment aware". You would pass the environment name (DEV, QA, etc) at the command line to the app, and then the app is "smart" enough to figure out the environment-specific configuration values at run-time. The app could fetch the values from flat files deployed along with the app, or from a central configuration service.
Applications are not "smart" as they are in #1, and simply fetch configuration by property name from config files deployed with the app. The values of these properties are injected into the config files at deploy-time by the install program/script. That install script takes the environment name and fetches all relevant configuration values from a central configuration service.
Question
How would/have you achieved a configuration solution that solves these problems and supports these desired features? Am I on target with the two possible solutions? Do you have a preference between those solutions? Also, please feel free to tell me that I'm thinking about the problem all wrong. Any feedback would be greatly appreciated.
We've all run into these kinds of things, particularly in large organizations. I think it's most important to manage your own expectations first, and also ask whether it's really necessary to tell every system and subsystem on a given box to "change to DEV mode" or "change to PROD mode". My personal recommendation is as follows:
Make individual boxes responsible for a different stage - i.e. "this is a DEV box", and "this is a PROD box".
Collect as much of the configuration that differs from box to box in one location, even if it requires soft links or scripts that collect the information to then print out.
A. This way, you can easily "dump this box's configuration" in two places and see what differs, for example after a new deployment.
B. You can also make configuration changes separate from software changes, at least to some degree, which is a good way to root out bugs that happen at release time.
Then have everything base its configuration on something/somewhere that is not baked-in or hard-coded - just make sure to collect and document it in that one location. It almost doesn't matter what the mechanism is, which is a good thing, because some systems just don't want to be forced to use some mechanisms or others.
Sorry if this is too general an answer - the question was very general. I've worked in several large software-based organizations before, and this seemed to be the best approach. Using a standalone server as "one unit of deployment" is the most realistic scenario (though sometimes its expensive), since applications affect each other, and no matter how careful you are, you destabilize a whole system when you move any given gear or cog.
The alternative gets very complex very quickly. You need to start rewriting the applications that you have control over in order to have them accept a "DEV" switch, and you end up adding layers of kludge to the ones you don't have control over. Usually, the ones you don't have control over at least base their properties on something defined on a system-wide level, unless they are "calling the mothership for instructions".
It's easier to redirect people to a remote location and have them "use DEV" vs "use PROD" than it is to "make this machine run like DEV" vs "make this machine run like PROD". And if you're mixing things up, like having a DEV task run together on the same box as a PROD task, then that's not a realistic scenario anyways: I guarantee that eventually you will be granting illegal DEV-only access to somebody on PROD, and you'll have a DEV task wipe out a PROD database.
Hope this helps. Let me know if you'd like to discuss more specifics involved.
I personally prefer solution 2 (the app should know itself, by its configuration, what environment it is running in). With solution 1 (pass the environment name as a startup parameter) the danger of using the wrong environment specifier is much too high. Accessing the TEST database from PROD code and vice versa may cause mayhem, if the two installed code bases are not of the same version, as is often the case.
My current project uses solution 1, but I don't like that. A previous project I worked on used a variation of solution 2: The build process generated one setup file for every environment, making sure that they contained the same code base but appropriate configuration paramters. That worked like a charm, but I know it contradicts the paradigm that the "exact same build files must be deployed everywhere".
I think I have asked a related, self-answered, question, before I read this one : How to organize code so that we can move and update it without having to edit the location of the configuration file? . So, on that basis, I provide an answer here. I don't like the idea of "smart" application (solution 1 here) for such a simple task as finding environment settings. It seems a complicated framework for something that should be simple. The idea of an install script (solution 2 here) is powerful, but it is useful to allow the user to change the content of the config file, but would it allow to change the location of this config file? What is this "central configuration service", where is it located? My answer is that I would go with option 2, if the goal is to set the content of the configuration file, but I feel that the issue of the location of this configuration file remains unanswered here.
If you're using JSON to store/transmit configuration (or can use JSON in your pre-deploy process to output to some other format) you can annotate key/property names for environment/context-specific values with arbitrary or environment-specific suffixes, and then dynamically prefer/discriminate them at build/deploy/run/render -time, while leaving un-annotated properties alone.
We have used this to avoid duplicating entire configuration files (with the associated problems well known) AND to reduce repetition. The technique is also perfect for internationalization (i18n) -- even within the same file, if desired.
Example, snippet of pre-processed JSON config:
var config = {
'ver': '1.0',
'help': {
'BLURB': 'This pre-production environment is not supported. Contact Development Team with questions.',
'PHONE': '808-867-5309',
'EMAIL': 'coder.jen#lostnumber.com'
},
'help#www.productionwebsite.com': {
'BLURB': 'Please contact Customer Service Center',
'BLURB#fr': 'S\'il vous plaît communiquer avec notre Centre de service à la clientèle',
'BLURB#de': 'Bitte kontaktieren Sie unseren Kundendienst!!1!',
'PHONE': '1-800-CUS-TOMR',
'EMAIL': 'customer.service#productionwebsite.com'
},
}
... and post-processed (in this case, at render time) given dynamic, browser-environment-known location.hostname='www.productionwebsite.com' and navigator.language of 'de'):
prefer(config,['www.productionwebsite.com','de']); // prefer(obj,string|Array<string>)
JSON.stringify(config); // {
'ver': '1.0',
'help': {
'BLURB': 'Bitte kontaktieren Sie unseren Kundendienst!!1!',
'PHONE': '1-800-CUS-TOMR',
'EMAIL': 'customer.service#productionwebsite.com'
}
}
If a non-annotated ('base') property has no competing annotated property, it is left alone (presumably global across environments) otherwise its value is replaced by an annotated value, if the suffix matches one of the inputs to the preference/discrimination function. Annotated properties that do not match are dropped entirely.
You can mix and match this behaviour to annotate configuration to achieve distinctions of global, default, specific that are (assuming you're sensible) readable with zero/minimal duplication.
The single, recursive prefer() function (as we're calling it, lacking the need or desire to make an entire project/framework out of it) we've developed so far (see jsFiddle, with inline docs) goes a bit further than this simple example, and (explained in greater detail here) handles deeply-nested configuration objects, as well as preferential ordering and (if you need to stay flat) combination of suffixes.
The function relies on JS ability to reference object properties as strings, dynamically, and tolerate # and & delimiters in property names which are not valid in dot-notation syntax but consequently (help) prevent developers from breaking this technique by accidentally referring to pre-processed/annotated attributes in code (unless they, non-conventionally don't prefer to use dot-notation.)
We have yet to have this break anything for us, nor have we been schooled on any fundamental flaws of this technique, beyond irresponsible/unintended usage or investment/fondness for existing frameworks/techniques that pre-exist. We have also not profiled it for performance (we only tend to run this once per build/session, etc.) so in your own usage, YMMV.
Most configurations transmitted client-side of course would not want to contain sensitive pre-production values, so one could (should!) use the same function to generate a production-only version (with no annotations) in pre-deploy, while still enjoying a SINGLE configuration file upstream in your process.
Further, if you're doing this for i18n, you may not want the entire wad going over the wire, so could process it server-side (cached or live, etc.) or pre-process it in build/deploy by splitting into separate files, but STILL enjoying a single source of truth as early in your workflow as possible.
We have not explored implementing the same function in Java (or C#, PERL, etc.) assuming it's even possible (with some exotic reflection maybe?) but a build environment that includes NodeJS could farm that step out easily.
Well if it suits your needs and you have no problem of storing the connection strings in the source control repository, you could create files like:
appsettings.dev.json
appsettings.qa.json
appsettings.staging.json
And choose the right one in the deployment script and rename it to the actual appsettings.json, which is then read by your app.
I'm trying to come up with a way to make it easy to switch out our "mock" data services and our live ones. Basically, we'll have live servers with real web services, but for whatever reason, a developer may want to load data from static files (file urls).
I figured I would solve this problem by creating categories that override the methods that fetch the data, thus leaving original code untouched (it has no concept of the "mock" data). I don't want to litter my code with #ifdef.
I can put an #ifdef at the very beginning of each file that has categories in it, and I can set a custom flag in the configuration settings, but I'd rather just have a way to include or exclude the files depending on the configuration. Is that possible? How do you solve this problem?
See http://lists.apple.com/archives/xcode-users/2009/Jun/msg00153.html
The trick is to define EXCLUDED_SOURCE_FILE_NAMES in the configuration you want to exclude the files from, and set the value of that custom build setting to a list of the file names (or a pattern that matches those, and only those, file names).
I would recommend creating two targets one of which has the mock categories included and another one which does not.
When you want to test, just build the target containing the mock categories. Everything else can remain identical.
If you would like to add a file but do not wont to compile it. Go to (for all your targets) project>build phases>compile source and take out the file that you do not want to compile.