In Cassandra Query Language (CQL), there is a handy command called source which allows user to execute the cql command stored in an external file.
SOURCE
Executes a file containing CQL statements. Gives the output for each
statement in turn, if any, or any errors that occur along the way.
Errors do NOT abort execution of the CQL source file.
Usage:
SOURCE '<file>';
But I am wondering if it is possible to allow this external file to take additional input arguments.
For example, suppose I would like to develop the following cql file with two input arguments:
create keyspace $1 with
strategy_class='SimpleStrategy' and
strategy_options:replication_factor=$2;
and would like to execute this cql in cqlsh by something like:
source 'cql-filename' hello_world 3
I developed the above example cql, stored it in a file called create-keyspace.cql, and tried some possible commands that I can come up with, but none of them works.
cqlsh> source 'create-keyspace.cql'
create-keyspace.cql:2:Invalid syntax at char 17
create-keyspace.cql:2: create keyspace $1 with strategy_class='SimpleStrategy' and strategy_options:replication_factor=$2;
create-keyspace.cql:2: ^
cqlsh> source 'create-keyspace.cql' hello_world 3
Improper source command.
cqlsh> source 'create-keyspace.cql hello_world 3'
Could not open 'create-keyspace.cql hello_world 3': [Errno 2] No such file or directory: 'create-keyspace.cql hello_world 3'
Can I know whether CQl has this type of supports? If yes, then how should I do it properly?
cqlsh is not really intended to be a scripting environment. It sounds like you'd be better served by using the Python CQL driver: https://github.com/datastax/python-driver
cqlsh only supports one parameter, the file containing CQL statements:
http://docs.datastax.com/en/cql/3.1/cql/cql_reference/source_r.html
It's a python-based command-line client. You can see its source code by looking for a file named cqlsh.py on the official Cassandra repo:
http://git-wip-us.apache.org/repos/asf/cassandra.git
And doing a search for SOURCE inside that file to see how it's handled.
Related
I would like to execute a gradle luqibase plugin diffChangelog task with my custom arguments from command line.
I DO NOT want to add/modify any of the project files, no modifications of build.gradle, no gradle.properties or such i just want to run a task and pass its parameters from command line and i am so far unable to do so i would like to distribute my script that executes this task in one bash file.
I have a problem even figuring out how to pass parameters to a gradle task, moreover even the format of the arguments is confusing - there are documentation snippets pointing that i should use camelCase or hyphenated version also zero/one/two hyphens are possible in the beginning . Additionally can either use -P or -D to pass arguments to gradle so far none of it seem to work it looks like the arguments are not being passed at all.
I would like to execute something like:
./gradlew diffChangelog --url=AA --username=BB --password=CC --reference-username=DD --reference-password=EE --reference-url=FF --changelog-gile=GG
Of course proper values will be provided by inline.
Is there a concise way to do so? So far googling up for the solution results in multiple complex explanations requiring modification of existing files and then passing arguments, is there really no way of just running a gradle task with arguments or am i missing something?
Update:
The error i am alyways getting is:
liquibase.exception.CommandValidationException: Invalid argument '--reference-url': missing required argument
You should check what end of line you have. This can sometimes be resolved by changing the end of line from from windows eol to linux.
Reference:
Unexpected error running Liquibase: Unexpected value [...] (options must start with a '--') && howTo? diff w/ properties file
I'm doing one project for puppet, however currently stuck in one logic.
Thus, want to know can we fetch variable from .yaml, .json or plain text file in puppet manifest file.
For example,
My puppet manifest want to create user but the variable exist in the .yaml or any configuration file, hence need to fetch the varibale from the outside file. The puppet manifest also can do looping if it exist multiple users in .yaml file.
I read about hiera but let say we are not using hiera is there any possible way.
There are a number of ways you can do this using a combination of built-in and stdlib functions, at least for YAML and JSON.
Using the built-in file function and the parseyaml or parsejson stdlib functions:
Create a file at mymodule/files/myfile.yaml:
▶ cat files/myfile.yaml
---
foo: bar
Then in your manifests read it into a string and parse it:
$myhash = parseyaml(file('mymodule/myfile.yaml'))
notice($myhash)
That will output:
Notice: Scope(Class[mymodule]): {foo => bar}
Or, using the loadyaml or loadjson stdlib functions:
$myhash = loadyaml('/etc/puppet/data/myfile.yaml')
notice($myhash)
The problem with that approach is that you need to know the path to file on the Puppet master. Or, you could use a Puppet 6 deferred function and read the data from a file on the agent node.
(Whether or not you should do this is another matter entirely - hint: answer is you almost certainly should be using Hiera - but that isn't the question you asked.)
Usually I get command outputs in variables like this:
res = `find . -name my_script.sh`. Then I can parse the output for what I am interested in.
How can I get the output of a command executed by a machine_execute resource ?
machine_execute 'Check IPA status' do
command 'ipactl status'
machine 'IPA_Admin_server'
end
You can't, Chef resources don't generally have outputs. In some cases the support an output API (like the AWS provisioning driver's aws_object helpers) but for something like this you would need to get the low-level Machine object and call its execute method. Take a look at how the resource is implemented for an example. You might also want to skip Provisioning's transport layer and use Train as we are probably going to try and centralize on that library.
I'm trying to learn how to use Common-Lisp's asdf, and I have the following code:
(asdf:defsystem example
:serial t
:components ((:file "first")
(:file "second")))
However, I keep getting the error:
Condition of type: SIMPLE-ERROR
Invalid relative pathname #P"first.lisp" for component ("example" "first")
I'm launching the repl in the same directory as these two Lisp files, but I don't understand why there is an error. What am I missing? I'm using ECL on Windows
ASDF uses *load-pathname* or *load-truename* to resolve the full paths to the system's components. If you enter the (asdf:defsystem ...) form on the REPL, these variables are not set.
Write the defsystem form into a file, then load it like (load "example.asd").
As part of a little project, I'm writing a shell in Ada. As such, when I was investigating the system calls, I learned that there are three ways to do it.
The POSIX system calls, which are probably the least reliable.
Passing the arguments along to C's system(), which I didn't really want to do, since this was about writing the emulator in Ada and not C.
Using GNAT's runtime libraries.
I chose to go for the last option, considering this to be the most "Ada-like" of the choices. I found a code snippet on RosettaCode here. I copied and pasted it and compiled it after changing the "cmd.exe" to "ls" and removing the second argument definition. However, nothing happens when I run the executable. The shell just goes right back to the prompt. I have tested this on two different computers, one running Fedora 21, the other Debian Jessie. Here's what I've done to test it:
Seen if lacking an arguments string caused it
Checked if any of the file descriptors in GNAT's libraries are mis-named
Redirected both stderr and stdin to stdout just to see if GNAT was dumping them to the wrong FD anyway.
Looked thoroughly through the System.OS_lib library file, and there seems to be no reason.
Googled it, but GNAT's own page on the GCC website is very poorly documented.
For now I'm using the C.Interface system in the preparation of my shell, but I'm dissatisfied with this. I'm new to Ada and have only been tinkering with it for a month or so now, so if there's some kind of Ada wisdom here that would help I'm not in on it.
UPDATE: I have tried running it with absolute path, both to /usr/bin and /bin locations, and it doesn't work. Interestingly, the result code returned by the operating system is 1, but I don't know what that means. A quick search suggests that it's for "all general errors", and another site suggests that it's for "incorrect functions".
I had to tweak the RosettaCode example a little to run /bin/ls on Debian Linux, but it does run as expected...
with Ada.Text_IO; use Ada.Text_IO;
with Gnat.OS_Lib; use Gnat.OS_Lib;
procedure Execute_Synchronously is
Result : Integer;
Arguments : Argument_List :=
( 1=> new String'("-al")
);
begin
Spawn
( Program_Name => "/bin/ls",
Args => Arguments,
Output_File_Descriptor => Standout,
Return_Code => Result
);
for Index in Arguments'Range loop
Free (Arguments (Index));
end loop;
end Execute_Synchronously;
Changes :
my Gnat (FSF Gnat 4.92 from Debian Jessie) warned about System.OS_Lib, recommending Gnat.OS_Lib instead. (Which simply renames System.OS_Lib .... why???
System.OS_Lib comments:
-- Note: this package is in the System hierarchy so that it can be directly
-- be used by other predefined packages. User access to this package is via
-- a renaming of this package in GNAT.OS_Lib (file g-os_lib.ads).
Program name including path.
Arguments. The first time I ran it, it displayed the details of "ls" itself, because it was given its own name as the first argument, so I deleted that to see the current directory instead.
Notes :
the best information ot the available subprograms and their arguments is usually in the package specs themselves in the "adainclude" folder : this is /usr/lib/gcc/x86_64-linux-gnu/4.9/adainclude on my Debian installation, locate system.ads will find yours. The specific files are: s-os_lib.ads for System.OS_Lib which exports Spawn and Standout, and a-textio.ads for Ada.Text_IO.
Standout is not the preferred way of accessing Standard Output : it's a file descriptor (integer), the preferred way would be the Standard_Output function from Ada.Text_IO which returns a File. However there doesn't seem to be an overload for Spawn which takes a File (nor would I expect one in this low level library) so the lower level file descriptor is used here.
Absent a shell, you'll need to search the PATH yourself or specify a full path for the desired executable:
Spawn (
Program_Name => "/bin/ls",
…
);
I have tried running it with absolute path…neither /usr/bin nor /bin locations work.
Use which to determine the full path to the executable:
$ which ls
/bin/ls