I need check a file not exist before i start my service in Systemd. I see two case in [Unit]:
ConditionPathExists=!/tmp/abc
and
ConditionPathExists=|!/tmp/abc
are they the same? Can anybody help me explain if they are different?
Sometime you specify multiple files like:
ConditionPathExists=!/tmp/abc
ConditionPathExists=!/tmp/abe
Now if any of the condition isn't satisfied, it doesn't start service. It's like and operations.
Now if you use:
ConditionPathExists=|!/tmp/abc
ConditionPathExists=|!/tmp/abe
If any of these conditions is satisfied, it will run the service.
Condition checks can be prefixed with a pipe symbol (|) in which case
a condition becomes a triggering condition. If at least one triggering
condition is defined for a unit, then the unit will be executed if at
least one of the triggering conditions apply and all of the
non-triggering conditions
It's like OR operations
Related
I currently have a Logic App that has an empty false path since the Logic App. The only reason I use a condition is because the LogicApp should stop when the condition is false. Is there a better alternative to stop a Logic App when a certain condition/statement is reached?
You can use Terminate action:
This action stops the run for a workflow instance, cancels any actions in progress, skips any remaining actions, and returns the specified status. For example, you can use the Terminate action when your logic app must exit completely from an error state. This action doesn't affect already completed actions and can't appear inside Foreach and Until loops, including sequential loops.
You can refer to my logic app:
This is my test result, it seems there is no problem：
Because "reasons", we know that when we use azureml-sdk's HyperDriveStep we expect a number of HyperDrive runs to fail -- normally around 20%. How can we handle this without failing the entire HyperDriveStep (and then all downstream steps)? Below is an example of the pipeline.
I thought there would be an HyperDriveRunConfig param to allow for this, but it doesn't seem to exist. Perhaps this is controlled on the Pipeline itself with the continue_on_step_failure param?
The workaround we're considering is to catch the failed run within our train.py script and manually log the primary_metric as zero.
thanks for your question.
I'm assuming that HyperDriveStep is one of the steps in your Pipeline and that you want the remaining Pipeline steps to continue, when HyperDriveStep fails, is that correct?
Enabling continue_on_step_failure, should allow the rest of the pipeline steps to continue, when any single steps fails.
Additionally, the HyperDrive run consists of multiple child runs, controlled by the HyperDriveConfig. If the first 3 child runs explored by HyperDrive fail (e.g. with user script errors), the system automatically cancels the entire HyperDrive run, in order to avoid further wasting resources.
Are you looking to continue other Pipeline steps when the HyperDriveStep fails? or are you looking to continue other child runs within the HyperDrive run, when the first 3 child runs fail?
Thanks!
I have a function.
Which for example goes like this:
Function start:
...
if statement{
set variable
}
if second if{}
contintue
This code I try to put into a UML, Activity diagram.
I wondered if my forking is done right, or do I need to use a forking symbol. So I have a split where it eventually gets into the if statement ( difference in totals). But after the if (or even if the if is not even executed) the next if statement will be executed (regardless of first if result).
If you want to have conditional paths you need to use decision nodes. Imagine a virtual token to represent the execution flow. When you are at an action that has multiple (unguarded) control flows leaving it, each will take a token (the UML spec calls that implicit fork) an execution will continue in parallel. So either you add guards to each of the outgoing control flows or you use a decision node. Though you should (or better must) use guards here too you have only a single token that will leave the decision node. Without proper guards it will be undecided which of the outgoing flows will take the token.
Implicit fork:
Only one token continues:
One token for sure and eventually a 2nd in parallel:
(I'm not 100% sure if that's really true. It's a notation I'd never use.)
Only one token continues, but not defined which (due to no guards):
We are trying to create an algorithm/heuristic that will schedule a delivery at a certain time period, but there is definitely a race condition here, whereby two conflicting scheduled items could be written to the DB, because the write is not really atomic.
The only way to truly prevent race conditions is to create some atomic insert operation, TMK.
The server receives a request to schedule something for a certain time period, and the server has to check if that time period is still available before it writes the data to the DB. But in that time the server could get a similar request and end up writing conflicting data.
How to circumvent this? Is there some way to create some script in the DB itself that hooks into the write operation to make the whole thing atomic? By putting a locking mechanism on that script? What makes the whole thing non-atomic is the read and the wire time between the server and the DB.
Whenever I run into race condition I think of one immediate solution QUEUE.
Step 1) What you can do is that instead of adding data to a database directly you can add it to queue without checking anything.
Step 2) A separate reader will read from the queue check DB for any conflict and take necessary action.
This is one of the ways to solve this If you implement any better solution please do share it.
Hope that helps
//STE1 IF RC EQ 1 THEN
....
//ENDIF
the return code is giving me FLUSH and all the other job is not executing becaue of this
can anyone help me on this.
is it because i havent given ELSE?
If you have conditions for running steps, either COND or IF, and the condition determines that a step is not run, then there is no "Return Code" from the step. The step is not run, it is FLUSHed, so there is no RC.
If the rest of the steps in your JOB are expecting to run on a RC=0, then you will have to change something.
Consult the JCL Reference, you have other options, like EVEN, ONLY, but these may not suit (haven't a clue, as don't know exactly what you are trying).
//STEPA
...
//STEPB
...
//STEPC
If STEPB depends on STEPA, so will not run with a zero RC from STEPA, you need to decide what is needed for STEPC. You have three situations: STEPB not run; runs with zero RC; runs with non-zero RC. What should STEPC do in each case.
If STEPC has no conditional processing, then it will just run whatever happens to STEPB (except an abend, and no EVEN).
If STEPC needs to run conditionally, you have to decide what it is about STEPA and STEPB which tells you how to run it.
If your JOB is big, and the conditions are complex, consider splitting it into separate JOBs and letting the Scheduler take care of it.
If your JCL is destined for Production, there should be JCL Standards to follow, and if you are unclear how to do something, you should consult those responsible for the Production JCL, they will tell you how they want it, and whether you even need be concerned about it (as they may well just re-write from scratch anyway).
When a particular step in a JOB is skipped due to COND parameter or any other reason, what will be the retuen code that will displayed in the spool