Notes

I am one of those people who function better by writing things down. One day, I realized that most of my notes don’t have to be private, so here they are - my second brain. Be warned that, if you stumble upon something here that doesn’t make sense to you, it isn’t meant to!

Move Git repository to an older commit

There are two ways of doing this and they both work with Git submodules. git reset --hard <commit-ID> Obviously risky as it will overwrite all local changes in the working directory. Works better when you only depend on Git submodules but don’t make any code changes to them (such as Hugo themes). Or: git checkout <commit-ID>

Today I learnt

Pytorch: x += 1 and x = x + 1 are not equivalent in Pytorch! The former is in-place and the latter is not, so be careful. More explanation is available here: x = x + 1 is not in-place, because it takes the objects pointed to by x, creates a new Variable, adds 1 to x putting the result in the new Variable, and overwrites the object referenced by x to point to the new var. There are no in-place modifications, you only change Python references (you can check that id(x) is different before and after that line). ...

First kid

We are expecting our first baby soon, sometime in mid November! When I learnt about this, it took awhile for the feeling to sink in. I am obviously super-excited and looking forward to when the kiddo arrives. I am also intimidated by the unknowns: I’ve heard some rumors but will only understand them when the time comes.

Get error rate for an AWS Step Function state machine through CloudWatch

Step Function emits the following execution metrics for each state machine: ExecutionsSucceeded. ExecutionsAborted. ExecutionsFailed. ExecutionsTimedOut. We can get the overall error rate for a given state machine by doing the following: aws cloudwatch get-metric-data \ --region us-east-1 \ --start-time 2020-06-01T00:00:00Z \ --end-time 2020-08-01T01:00:00Z \ --scan-by TimestampAscending \ --metric-data-queries ' [ { "Id": "executionsAborted1", "MetricStat": { "Metric": { "Namespace": "AWS/States", "MetricName": "ExecutionsAborted", "Dimensions": [ { "Name": "StateMachineArn", "Value": "<state-machine-ARN>" } ] }, "Period": 300, "Stat": "Sum" }, "ReturnData": false }, { "Id": "executionsFailed1", "MetricStat": { "Metric": { "Namespace": "AWS/States", "MetricName": "ExecutionsFailed", "Dimensions": [ { "Name": "StateMachineArn", "Value": "<state-machine-ARN>" } ] }, "Period": 300, "Stat": "Sum" }, "ReturnData": false }, { "Id": "executionsSucceeded1", "MetricStat": { "Metric": { "Namespace": "AWS/States", "MetricName": "ExecutionsSucceeded", "Dimensions": [ { "Name": "StateMachineArn", "Value": "<state-machine-ARN>" } ] }, "Period": 300, "Stat": "Sum" }, "ReturnData": false }, { "Id": "executionsTimedOut1", "MetricStat": { "Metric": { "Namespace": "AWS/States", "MetricName": "ExecutionsTimedOut", "Dimensions": [ { "Name": "StateMachineArn", "Value": "<state-machine-ARN>" } ] }, "Period": 300, "Stat": "Sum" }, "ReturnData": false }, { "Id": "errorRate", "Expression": "1 - (executionsSucceeded1)/(executionsSucceeded1 + executionsTimedOut1 + executionsFailed1 + executionsAborted1)" } ] '

Get error rate for AWS API Gateway through CloudWatch

Top-level error rate: aws cloudwatch get-metric-data \ --region us-east-1 \ --start-time 2020-08-01T00:00:00Z \ --end-time 2020-08-02T00:00:00Z \ --scan-by TimestampAscending \ --metric-data-queries ' [ { "Id": "m1", "MetricStat": { "Metric": { "Namespace": "AWS/ApiGateway", "MetricName": "5XXError", "Dimensions": [ { "Name": "ApiName", "Value": "<service-name>" }, { "Name": "Stage", "Value": "<stage-name>" } ] }, "Period": 300, "Stat": "Average" } } ] ' Or, for API-level, just add relevant dimensions: ...

List Metrics from AWS CloudWatch

List error-metrics for an AWS API Gateway service: aws cloudwatch list-metrics \ --region us-east-1 \ --namespace AWS/ApiGateway \ --metric-name 5XXError \ --dimensions ' [ { "Name": "ApiName", "Value": "<service-name>" } ] ' Or all metrics for AWS Step Functions: aws cloudwatch list-metrics \ --region us-east-1 \ --namespace AWS/States

Manage AWS KMS Grants

Create aws kms create-grant \ --region us-east-1 \ --key-id <key-ARN> \ --grantee-principal <grantee-principal-role-ARN> \ --operations Encrypt Decrypt GenerateDataKey \ --constraints EncryptionContextSubset={'foo'='bar'} Note: The list of valid --operations can be found here. If you don’t want to supply encryption context, just omit the --constraints parameter. List aws kms list-grants \ --region us-east-1 \ --key-id <key-ARN> Retire aws kms retire-grant \ --region us-east-1 \ --grant-id <grant-id> \ --key-id <key-ARN>

Env variable to set default AWS region

export AWS_DEFAULT_REGION=us-west-2

Limit coffee intake

How many times do I have to get burnt before I understand not to drink too much coffee. And, no, it won’t be different this one time either because I didn’t sleep well so am tired today or because I am drinking the second cup before noon. (On the latter, I don’t know why things are so bad for me. It’s probably has to do with the way I make coffee, with an Aeropress, which leaves a higher concentration of caffeine in the body.) ...

Child-care search in Seattle

To ask Cancelation policy. Do they support monthly freezes? Any subsidies for Microsoft or Amazon employees? If we gave some date today, how flexible are they with us changing it later on? Bright horizons Infant program: 6 weeks to 1 year old. Belltown: $150 non-refundable fee. Can put 3 location preferences but you have to pay the highest amount out of the 3. $3090 per month until July 2021. Only full time. M-F. 7 am to 5:30 pm currently. However much time is needed. Jan 2020 had a lengthy waitlist. SLU: Same. Interbay: Same. Kiddie Academy Queen Anne. Full-time only. M-F, 7 am to 6:30 pm. Can’t leave for 10+ hours. 4-6 weeks to 1 year. Jan-Feb very popular. ~20 or so families on the wait-pool, only have 16 spaces but not all available. ~4 available. $2760 per month. Month-to-month with 4 week notice. Once enrolled, your spot is available until the child graduates at 4-5 years. Prices change based on child’s age. For e.g., next is $2610. Enrollment: $150 wait-pool/registration fee. Virtual tour: They check temperature before taking the child in today. Parents aren’t currently allowed to visit their children. 2 infant class. Teacher to children ratio: 1:4. Max 8 children in one class. 1:7 to 1:5 and 11-14 respectively for toddlers. Mothers currently not allowed to come feed. Food is labeled and stored in refrigerator. Food for infants required every day. Once older (7+ months), they offer meals which are included in the tuition. Infant program: Crib per infant. Sheets changed daily. Infant daily report over email/app. Daily notes (such as naps, meals, etc.). Parents provide all diapers, meals, extra clothes etc. for infants. Fresh, organic and sometimes cross-cultural food. Later on, Spanish language, yoga, music etc. If parents want to influence, discuss with teacher. Bi-weekly plans. Toddler program: Family style dining. Designated meal, out and nap time. No freeze or vacation credit: continue paying or leave. No subsidies for us. The sooner you join the wait pool, the higher your chance of getting a spot whenever you you want and whenever one comes up.