I'm trying to get a setting from a configuration file (preferably something simple like .ini or JSON, not XML). If the file or setting does not exist, I want to be able to fall back to retrieving an environment variable.
I'd prefer to use an existing library for working with JSON/INI and not parsing the file myself. However, most libraries I've found won't work if a file doesn't exist.
How would I access a configuration value from a file that may or may not exist in F#?
You can use File.Exists to test whether or not the file exists:
open System.IO
let getConfig file =
if File.Exists file
then "config from file"
else "config from somewhere else"
OpenExeConfiguration (despite it's name) can open an arbitrary config file.
There's also the ASP.NET vNext Configuration stuff, outlined in this article which is quite flexible - no idea how separable (or relevant to your actual use case) it is [aside from the fact that you could conditionally include the config file into the config manager depending on whether it exists a la Mark's answer].
In addition to type providers, FSharp.Data provides some basic parsers, including JSON. This allows you to do a runtime check using File.Exists and then parse using your preferred utility.
I took the following approach in FAKE:
if File.Exists "local.json" then
let localVarProps = JsonValue.Parse(File.ReadAllText"local.json").Properties
for key, jsonValue in localVarProps do
setEnvironVar key (jsonValue.AsString())
Related
In Data Integration module, I have created a mapping to load data from Csv file to Oracle table. I want to give a file pattern as the file name will have date in it. When I try to provide file pattern in the Source object, it is throwing the below error.
If someone can assist on letting me know how to load file with a file pattern, it will be very helpful.
Please let me know if you need any further details.
Try using a File Listener as the source for this mapping. In File Listener settings you can provide the pattern - and in turn, File Listener will trigger the mapping with the file found.
I use flume-1.8.0.
On the document, it says that I cannot set the directory pattern.
(Regular expression (and not file system patterns) can be used for filename only.)
But I have to set the directory pattern to get log from other system which controlled by other team.
Is there some solution to set directory path like /dir/201801/0101.log, /dir/201802/0001.log, ... ?
Use something like this for the file groups with file patterns i.e use the Regex ASCII pattern see https://en.wikipedia.org/wiki/Regular_expression for more details
a1.sources.r1.filegroups.f2 = /path/to/files/with/pattern/databundle_cnt_[0-9]{4}-[0-9]{2}-[0-9]{2}.csv
In your case I will advise
a1.sources.r1.filegroups.f2 = /dir/[0-9]{6}/[0-9]{4}.log
I have a script which saves some files at a given location. It works fine but when I send this code to someone else, he has to change the paths in the code. It's not comfortable for someone who does not know what is in that code and for me to explain every time where and how the code should be changed.
I want to get this path in a variable which will be taken from the configuration file. So it will be easier for everyone to change just this config file and nothing in my code. But I have never done this before and could not find any information on how I can do this in the internet.
PS: I do not have any code and I ask about an ultimate solution but it is really difficult to find something good in the internet about dxl, especially since I'm new with that. Maybe someone of you already does that or has an idea how it could be done?
DXL has a perm to read the complete context of a file into a variable: string readFile (string) (or Buffer readFile (string))
you can split the output by \n and then use regular expressions to find all lines that match the pattern
^\s*([^;#].*)\s*=\s*(.*)\s*$
(i.e. key = value - where comment lines start with ; or #)
But in DOORS I prefer using DOORS modules as configuration modules. Object Heading can be the key, Object Text can be the value.
Hardcode the full name of the configuration module into your DXL file and the user can modify the behaviour of the application.
The advantage over a file is that you need not make assumptions on where the config file is to be stored on the file system.
It really depends on your situation. You are going to need to be a little more specific about what you mean by "they need to change the paths in the code". What are these paths to? Are they DOORS module paths, are they paths to local/network files, or are the something else entirely?
Like user3329561 said, you COULD use a DOORS module as a configuration file. I wouldn't recommend it though, simply because that is not what DOORS modules were designed for. DOORS is fully capable of reading system files in one line at a time as well as all at once, but I can't recommend that option either until I know what types of paths you want to load and why.
I suspect that there is a better solution for your problem that will present itself once more information is provided.
I had the same problem, I needed to specify the path of my configuration file used in my dxl script.
I solved this issue passing the directory path as a parameter to DOORS.exe as follow:
"...\DOORS\9.3\bin\doors.exe" -dxl "string myVar = \"Hello Word\"
then in my dxl script, the variable myVar is a global variable.
I'm planning to do a program with Lua that will first of all read specific files
and get information from those files. So my first question is whats the "my documents" path name? I have searched a lot of places, but I'm unable to find anything. My second question is how can I use the first four letters of a file name to see which one is the newest made?
Finding the files in "my documents" then find the newest created file and read it.
The reading part shouldn't be a problem, but navigating to "my documents" and finding the newest created file in a folder.
For your first question, depends how robust you want your script to be. You could use Lua's builtin os.getenv() to get a variety of environment vars related to user, such as USERNAME, USERPROFILE, HOMEDRIVE, HOMEPATH. Example:
username = os.getenv('USERNAME')
dir = 'C:\\users\\' .. username .. '\\Documents'
For the second question, there is no builtin mechanism in Windows to have the file creation or modification timestamp as part of the filename. You could read the creation or modification timestamp, via a C extension you create or using an existing Lua library like lfs. Or you could read the contents of a folder and parse the filenames if they were named according to the pattern you mention. Again there is nothing built into Lua to do this, you would either use os.execute() or lfs or, again, your own C extension module, or combinations of these.
When my Grails application starts, I build up a data structure from a CSV file downloaded from a remote URL. If the file is not accessible, I'd like to fall back to a local copy. Currently processing the file in the service layer, initiated using a Quartz job.
What is the best practice, using Groovy, for reading a local resource in Grails?
Where should I stash the file?
How do I safely and properly read the file?
General-case answers will be very acceptable.
I think the best way to deal with this is to store the file's location in an externalized configuration file.
So, you'd determine a standardized location (such as /etc/myappname/CSVFileConfig.groovy), or pass the config file path in using an environment variable or something similar. See Externalized Configuration for examples.
Then you can simply add the actual path to the local file to that extenal config, like so:
// CSVFileConfig.groovy
my.custom.csv.path = ...
Finally, access it using normal config operations:
// in your Quartz job
def path = grailsApplication.config.my?.custom?.csv?.path
if(!path) {
// no file to load
} else {
// load file
}
As far as reading the file, what are your primary concerns? If you are using a CSV library, such as OpenCSV (used in most of the Grails libraries for CSV parsing), it will handle the opening and parsing of the file.
For security issues beyond that, I'm not sure how to handle them in a generic way. It will depend on your specific scenario. I think the one coming from a URL has a higher risk factor.