Moments | Snapchat , built with Xamarin.Forms and Azure | Form library
kandi X-RAY | Moments Summary
kandi X-RAY | Moments Summary
Moments is a Snapchat clone built using Xamarin.Forms and Microsoft Azure. Text messaging is out-of-style! Everyone these days sends selfies, pictures of their food, and emojis instead. Duh. Moments allows you to send those selfies and pictures of your food to those that love you. You can even draw funny pictures on them! That's not even the best part! Moments is completely open-source, so you can create your own SnapChat clone using Xamarin and Azure in just a few minutes. But seriously. Moments is awesome! If you've ever wondered how to use custom renderers in Xamarin.Forms, upload blobs from your Xamarin apps using Azure Storage, or how to maximize shared code with Plugins for Xamarin, Moments can show you how. If you think this is awesome, please share a link to this repository on Twitter, LinkedIn, whatever. It would be much appreciated! :).
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Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of Moments
Moments Key Features
Moments Examples and Code Snippets
Lines of Code : 75License : Non-SPDX (Apache License 2.0)
Copydef weighted_moments(x, axes, frequency_weights, name=None, keep_dims=None,
keepdims=None):
"""Returns the frequency-weighted mean and variance of `x`.
Args:
x: A tensor.
axes: 1-d tensor of int32 values; these are t def moments(
x,
axes,
shift=None, # pylint: disable=unused-argument
name=None,
keep_dims=None,
keepdims=None):
"""Calculate the mean and variance of `x`.
The mean and variance are calculated by aggregating the contents o def moments_v2(
x,
axes,
shift=None,
keepdims=False,
name=None):
"""Calculates the mean and variance of `x`.
The mean and variance are calculated by aggregating the contents of `x`
across `axes`. If `x` is 1-D and `axes = Community Discussions
Trending Discussions on Moments
QUESTION
I have a website that drags an element over to a drop zone. The problem is when you drop an element, a lot stuff in the back end has to update. Due to this, the cursor position won't update until to move the cursor.
This JSFiddle sort of reproduces the problem
When you drag the line over to the bottom div and don't move the cursor, it still thinks the cursor location is in the original spot before it dragging, so the hover still displays red. Once you move the cursor it updates.
This is the code:
HTML:
...ANSWER
Answered 2022-Feb-18 at 08:47I think you better use dragend or dragleave event listener.
not :hover.
See the difference as you try it.
dragend will work the way you want it to.
However, if you drag the li to a place other than div2, it returns and then the red color disappears.
QUESTION
Just today, whenever I run terraform apply, I see an error something like this: Can't configure a value for "lifecycle_rule": its value will be decided automatically based on the result of applying this configuration.
It was working yesterday.
Following is the command I run: terraform init && terraform apply
Following is the list of initialized provider plugins:
...ANSWER
Answered 2022-Feb-15 at 13:49Terraform AWS Provider is upgraded to version 4.0.0 which is published on 10 February 2022.
Major changes in the release include:
- Version 4.0.0 of the AWS Provider introduces significant changes to the aws_s3_bucket resource.
- Version 4.0.0 of the AWS Provider will be the last major version to support EC2-Classic resources as AWS plans to fully retire EC2-Classic Networking. See the AWS News Blog for additional details.
- Version 4.0.0 and 4.x.x versions of the AWS Provider will be the last versions compatible with Terraform 0.12-0.15.
The reason for this change by Terraform is as follows: To help distribute the management of S3 bucket settings via independent resources, various arguments and attributes in the aws_s3_bucket resource have become read-only. Configurations dependent on these arguments should be updated to use the corresponding aws_s3_bucket_* resource. Once updated, new aws_s3_bucket_* resources should be imported into Terraform state.
So, I updated my code accordingly by following the guide here: Terraform AWS Provider Version 4 Upgrade Guide | S3 Bucket Refactor
The new working code looks like this:
QUESTION
ANSWER
Answered 2022-Feb-13 at 08:47This problem may arise as a result of the internet connection. The simple way to resolve this problem is to reload the Overleaf editor by refreshing your browser.
QUESTION
I am trying to solve a BVP problem (Cosserat rod ODE) with gekko. The goal is to find the initial conditions nsol and msol (which correspond to the internal forces and moments of the rod) that minimize the cost function (the position of the final point of the rod), when integrating, the cosserat equations gives us P, R, nsol, msol, which correspond to the position, orientation, internal forces and moment in a section of the rod.
but I keep getting this error:
Exception: @error: Equation Definition Equation without an equality (=) or inequality (>,<) false STOPPING...
I am a beginner with gekko and although I have seen multiple threads with the same error, the source of the error seems to be different everytime. Could anyone please point me in the right direction ? Thank you very much
...ANSWER
Answered 2021-Dec-22 at 13:36One way to troubleshoot these types of errors is to inspect the gk0_model.apm model file in the run directory m.path. I modified the code to open the folder with m.open_folder() and the apm file:
QUESTION
Is there a way to create a distribution curve given the 1st through 4th moments (mean, variance or standard deviation, skewness, and kurtosis)? Here is a small table of the descriptive statistics. The fifth variable has stronger positive skew and larger kurtosis than the rest, and leads me to believe a non-normal distribution may need to be used.
...ANSWER
Answered 2021-Dec-16 at 03:10Use the PearsonDS package, the pearson0 family creates "normal" distributions matching specified moments, but other options are available.
QUESTION
I created a documentdb cluster by terraform. When I run terraform plan, it tried to destroy the cluster and rebuild it, but I didn't change the value file.
below is the main content of terraform script,
...ANSWER
Answered 2021-Dec-15 at 04:45Changing kms key for your DocumentDB requires replacement. There is not much you can do about that.
You are correctly referring to default kms (kms_key_id = data.aws_kms_alias.rds.arn). But since you had different kms key before, a replacement is required. If so, make sure you backup your db before that.
QUESTION
I've been working through a Terraform (+ CI/CD) workshop which was taught in an earlier version of Terraform, but I decided to it in 1.0.11 with AWS provider 3.65.0.... just to see what sort of the difference would be. I've hit a blocker when dealing with ACM to get the certificate, and I need some advice on how to proceed.
The error I'm getting is during the plan stage:
...ANSWER
Answered 2021-Dec-08 at 00:16TL;DR: This fixes your example from my testing:
QUESTION
I want to use Youtube API on my project where user can search for videos and it displays search results as the user is typing. I am only familiar with python and django. So, I am using a tutorial to do the JS part to add ajax. Everything in my code is exactly as shown in the tutorial but mine is not working.
So my javascript for ajax is:
...ANSWER
Answered 2021-Nov-29 at 19:47I was using Crispy Forms on that page for my forms and it was stopping the code from running. I dont know why but once I removed crispy forms the code worked fine. Instead of crispy forms I am using widget tweaks now.
QUESTION
I've encountered some strange behaviour of delphi XE3 compiler (i compile for x86 architecture).
Imagine i have class with one field - custom record with several field of simple types:
...ANSWER
Answered 2021-Nov-08 at 15:06This is a bug that is still present in Delphi 11 (thanks to LU RD for confirming that). You should submit a bug report to Quality Portal.
In the meantime, I think that you can work around it by making the assignment in TPage rather than TParagraph. Like this:
QUESTION
First of all, I've tried all recommendations from C# DNS-related SO threads and other internet articles - messing with ServicePointManager/ServicePoint settings, setting automatic request connection close via HTTP headers, changing connection lease times - nothing helped. It seems like all those settings are intended for fixing DNS issues in long-running processes (like web services). It even makes sense if a process would have it's own DNS cache to minimize DNS queries or OS DNS cache reading. But it's not my case.
The problemOur production infrastructure uses HA (high availability) DNS for swapping server nodes during maintenance or functional problems. And it's built in a way that in some places we have multiple CNAME-records which in fact point to the same HA A-record like that:
- eu.site1.myprodserver.com (CNAME) > eu.ha.myprodserver.com (A)
- eu.site2.myprodserver.com (CNAME) > eu.ha.myprodserver.com (A)
The TTL of all these records is 60 seconds. So when the European node is in trouble or maintenance, the A-record switches to the IP address of some other node.
Then we have a monitoring utility which is executed once in 5 minutes and uses both site1 and site2. For it to work properly both names must point to the same DC, because data sync between DCs doesn't happen that fast. Since both CNAMEs are in fact linked to the same A-record with short TTL at a first glance it seems like nothing can go wrong. But it turns out it can.
The utility is written in C# for .NET Framework 4.7.2 and uses HttpClient class for performing requests to both sites. Yeah, it's him again.
We have noticed that when a server node switch occurs the utility often starts acting as if site1 and site2 were in different DCs. The pattern of its behavior in such moments is strictly determined, so it's not like it gets confused somewhere in the middle of the process - it incorrecly resolves one or both of these addresses from the very start.
I've made another much simpler utility which just sends one GET-request to site1 and then started intentionally switching nodes on and off and running this utility to see which DC would serve its request. And the results were very frustrating.
Despite the Windows DNS cache already being updated (checked via ipconfig and Get-DnsClientCache cmdlet) and despite the overall records' TTL of 60 seconds the HttpClient keeps sending requests to the old IP address sometimes for another 15-20 minutes. Even when I've completely shut down the "outdated" application server - the utility kept trying to connect to it, so even connection failures don't wake it up.
It becomes even more frustrating if you start running ipconfig /flushdns in between utility runs. Sometimes after flushdns the utility realizes that the IP has changed. But as soon as you make another flushdns (or this is even not needed - I haven't 100% clearly figured this out) and run the utility again - it goes back to the old address! Unbelievable!
And add even more frustration. If you resolve the IP address from within the same utility using Dns.GetHostEntry method (which uses cache as per this comment) right before calling HttpClient, the resolve result would be correct... But the HttpClient would anyway make a connection to an IP address of seemengly his own independent choice. So HttpClient somehow does not seem to rely on built-in .NET Framework DNS resolving.
So the questions are:
- Where does a newly created .NET Framework process take those cached DNS results from?
- Even if there is some kind of a mystical global .NET-specific DNS cache, then why does it absolutely ignore TTL?
- How is it possible at all that it reverts to the outdated old IP address after it has already once "understood" that the address has changed?
P.S. I have worked this all around by implementing a custom HttpClientHandler which performs DNS queries on each hostname's first usage thus it's independent from external DNS caches (except for caching at intermediate DNS servers which also affects things to some extent). But that was a little tricky in terms of TLS certificates validation and the final solution does not seem to be production ready - but we use it for monitoring only so for us it's OK. If anyone is interested in this, I'll show the class code which somewhat resembles this answer's example.
Update 2021-10-08The utility works from behind a corporate proxy. In fact there are multiple proxies for load balancing. So I am now also in process of verifying this:
- If the DNS resolving is performed by the proxies and they don't respect the TTL or if they cache (keep alive) TCP connections by hostnames - this would explain the whole problem
- If it's possible that different proxies handle HTTP requests on different runs of the utility - this would answer the most frustrating question #3
The answer to "Does .NET Framework has an OS-independent global DNS cache?" is NO. HttpClient class or .NET Framework in general had nothing to do with all of this. Posted my investigation results as an accepted answer.
...ANSWER
Answered 2021-Oct-14 at 21:32HttpClient, please forgive me! It was not your fault!
Well, this investigation was huge. And I'll have to split the answer into two parts since there turned out to be two unconnected problems.
1. The proxy server problemAs I said, the utility was being tested from behind a corporate proxy. In case if you haven't known (like I haven't till the latest days) when using a proxy server it's not your machine performing DNS queries - it's the proxy server doing this for you.
I've made some measurements to understand for how long does the utility keep connecting to the wrong DC after the DNS record switch. And the answer was the fantastic exact 30 minutes. This experiment has also clearly shown that local Windows DNS cache has nothing to do with it: those 30 minutes were starting exactly at the point when the proxy server was waking up (was finally starting to send HTTP requests to the right DC).
The exact number of 30 minutes has helped one of our administrators to finally figure out that the proxy servers have a configuration parameter of minimal DNS TTL which is set to 1800 seconds by default. So the proxies have their own DNS cache. These are hardware Cisco proxies and the admin has also noted that this parameter is "hidden quite deeply" and is not even mentioned in the user manual.
As soon as the minimal proxies' DNS TTL was changed from 1800 seconds to 1 second (yeah, admins have no mercy) the issue stopped reproducing on my machine.
But what about "forgetting" the just-understood correct IP address and falling back to the old one?Well. As I also said there are several proxies. There is a single corporate proxy DNS name, but if you run nslookup for it - it shows multiple IPs behind it. Each time the proxy server's IP address is resolved (for example when local cache expires) - there's quite a bit of a chance that you'll jump onto another proxy server.
And that's exactly what ipconfig /flushdns has been doing to me. As soon as I started playing around with proxy servers using their direct IP addresses instead of their common DNS name I found that different proxies may easily route identical requests to different DCs. That's because some of them have those 30-minutes-cached DNS records while others have to perform resolving.
Unfortunately, after the proxies theory has been proven, another news came in: the production monitoring servers are placed outside of the corporate network and they do not use any proxy servers. So here we go...
2. The short TTL and public DNS servers problemThe monitoring servers are configured to use 8.8.8.8 and 8.8.4.4 Google's DNS servers. Resolve responses for our short-lived DNS records from these servers are somewhat weird:
- The returned TTL of CNAME records swings at around 1 hour mark. It gradually decreases for several minutes and then jumps back to 3600 seconds - and so on.
- The returned TTL of the root A-record is almost always exactly 60 seconds. I was occasionally receiving various numbers less than 60 but there was no any obvious humanly-percievable logic. So it seems like these IP addresses in fact point to balancers that distribute requests between multiple similar DNS servers which are not synced with each other (and each of them has its own cache).
Windows is not stupid and according to my experiments it doesn't care about CNAME's TTL and only cares about the root A-record TTL, so its client cache even for CNAME records is never assigned a TTL higher than 60 seconds.
But due to the inconsistency (or in some sense over-consistency?) of the A-record TTL which Google's servers return (unpredictable 0-60 seconds) the Windows local cache gets confused. There were two facts which demonstrated it:
- Multiple calls to
Resolve-DnsNamefor site1 and site2 over several minutes with random pauses between them have eventually led toGet-ClientDnsCacheshowing the local cache TTLs of the two site names diverged on up to 15 seconds. This is a big enough difference to sometimes mess the things up. And that's just my short experiment, so I'm quite sure that it might actually get bigger. - Executing
Invoke-WebRequestto each of the sites one right after another once in every 3-5 seconds while switching the DNS records has let me twicely face a situation when the requests went to different DCs.
Conclusion?The latter experiment had one strange detail I can't explain. Calling
Get-DnsClientCacheafterInvoke-WebRequestshows no records appear in the local cache for the just-requested site names. But anyway the problem clearly has been reproduced.
It would take time to see whether my workaround with real-time DNS resolving would bring any improvement. Unfortunately, I don't believe it will - the DNS servers used at production (which would eventually be used by the monitoring utility for real-time IP resolving) are public Google DNS which are not reliable in my case.
And one thing which is worse than an intermittently failing monitoring utility is that real-world users are also relying on public DNS servers and they definitely do face problems during our maintenance works or significant failures.
So have we learned anything out of all this?
- Maybe a short DNS TTL is generally a bad practice?
- Maybe we should install additional routers, assign them static IPs, attach the DNS names to them and then route traffic internally between our DCs to finally stop relying on DNS records changing?
- Or maybe public DNS servers are doing a bad job?
- Or maybe the technological singularity is closer than we think?
I have no idea. But its quite possible that "yes" is the right answer to all of these questions.
However there is one thing we surely have learned: network hardware manufacturers shall write their documentation better.
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