Tilde character in file path in a shell must expand to the absolute path of the home directory

[amej]

Proposal

** Tilde symbol in a file path needs to expand to absolute path of home directory of the user as per the *nix **

Bug Report

What did you do?
As per instructions given in https://prometheus.io/docs/introduction/first_steps/; start prometheus by executing
./prometheus --config.file=~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml

What did you expect to see?
In the ~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml ; I expected the ~asathe to expand to home directory of asathe ( in my case; it is /home/pnq/asathe )
What did you see instead? Under which circumstances?
prometheus reported
level=error ts=2018-06-08T13:41:36.291212386Z caller=main.go:597 err="Error loading config couldn't load configuration (--config.file=~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml): open ~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml: no such file or directory"

Environment

• System information:

Linux 4.14.16-300.fc27.x86_64 x86_64 ```

• Prometheus version:

./prometheus --version
prometheus, version 2.3.0 (branch: HEAD, revision: 290d71791a507a5057b9a099c9d48703d86dc941)
  build user:       root@d539e167976a
  build date:       20180607-08:46:54
  go version:       go1.10.2

• Prometheus configuration file:

[asathe@localhost prometheus-2.3.0.linux-amd64]$ cat prometheus.yml 
# my global config
global:
  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
  # scrape_timeout is set to the global default (10s).

# Alertmanager configuration
alerting:
  alertmanagers:
  - static_configs:
    - targets:
      # - alertmanager:9093

# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
rule_files:
  # - "first_rules.yml"
  # - "second_rules.yml"

# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
  - job_name: 'prometheus'

    # metrics_path defaults to '/metrics'
    # scheme defaults to 'http'.

    static_configs:
    - targets: ['localhost:9090']
[asathe@localhost prometheus-2.3.0.linux-amd64]$ 

• Logs:

[root@localhost prometheus-2.3.0.linux-amd64]# ./prometheus --config.file=~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml 
level=info ts=2018-06-08T13:41:36.242555868Z caller=main.go:222 msg="Starting Prometheus" version="(version=2.3.0, branch=HEAD, revision=290d71791a507a5057b9a099c9d48703d86dc941)"
level=info ts=2018-06-08T13:41:36.242694699Z caller=main.go:223 build_context="(go=go1.10.2, user=root@d539e167976a, date=20180607-08:46:54)"
level=info ts=2018-06-08T13:41:36.2427562Z caller=main.go:224 host_details="(Linux 4.14.16-300.fc27.x86_64 #1 SMP Wed Jan 31 19:24:27 UTC 2018 x86_64 localhost.localdomain (none))"
level=info ts=2018-06-08T13:41:36.242800958Z caller=main.go:225 fd_limits="(soft=1024, hard=4096)"
level=info ts=2018-06-08T13:41:36.24340709Z caller=main.go:514 msg="Starting TSDB ..."
level=info ts=2018-06-08T13:41:36.249070562Z caller=web.go:426 component=web msg="Start listening for connections" address=0.0.0.0:9090
level=info ts=2018-06-08T13:41:36.272393842Z caller=main.go:524 msg="TSDB started"
level=info ts=2018-06-08T13:41:36.275782327Z caller=main.go:603 msg="Loading configuration file" filename=~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml
level=info ts=2018-06-08T13:41:36.27587218Z caller=main.go:402 msg="Stopping scrape discovery manager..."
level=info ts=2018-06-08T13:41:36.275922809Z caller=main.go:416 msg="Stopping notify discovery manager..."
level=info ts=2018-06-08T13:41:36.275960298Z caller=main.go:438 msg="Stopping scrape manager..."
level=info ts=2018-06-08T13:41:36.276101975Z caller=main.go:412 msg="Notify discovery manager stopped"
level=info ts=2018-06-08T13:41:36.287078035Z caller=manager.go:464 component="rule manager" msg="Stopping rule manager..."
level=info ts=2018-06-08T13:41:36.287120767Z caller=manager.go:470 component="rule manager" msg="Rule manager stopped"
level=info ts=2018-06-08T13:41:36.287138091Z caller=notifier.go:512 component=notifier msg="Stopping notification manager..."
level=info ts=2018-06-08T13:41:36.290181893Z caller=main.go:398 msg="Scrape discovery manager stopped"
level=info ts=2018-06-08T13:41:36.29078386Z caller=main.go:432 msg="Scrape manager stopped"
level=info ts=2018-06-08T13:41:36.290835358Z caller=main.go:588 msg="Notifier manager stopped"
level=error ts=2018-06-08T13:41:36.291212386Z caller=main.go:597 err="Error loading config couldn't load configuration (--config.file=~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml): open ~asathe/prometheus-2.3.0.linux-amd64/prometheus.yml: no such file or directory"
level=info ts=2018-06-08T13:41:36.291274804Z caller=main.go:599 msg="See you next time!"

[brian-brazil]

Tilde expansion is the responsibility of your shell on Unix. Which shell are you using?

If your shell doesn't support it, $HOME always works.

[amej]

Tilde expansion is the responsibility of your shell on Unix. Which shell are you using?

root@localhost ~]# file ~
/root: directory
[root@localhost ~]# file ~asathe/
/home/asathe/: directory
[root@localhost ~]# echo $HOME
/root
[root@localhost ~]# echo $SHELL
/bin/bash
[root@localhost ~]# rpm -q bash
bash-4.4.12-13.fc27.x86_64
[root@localhost ~]# 


[asathe@localhost node_exporter-0.16.0.linux-amd64]$ j=~asathe
[asathe@localhost node_exporter-0.16.0.linux-amd64]$ echo $j
/home/asathe

It is not mentioned in the documents, but the './prometheus --configfile= ..' needs to be executed as root user. In my scenario; I extracted prometheus into normal user's directory '~asathe/prometheus'.
I switched non-login/login-shell to root to execute prometheus binary. But; after switching the variable $HOME would store the home directory of root user. Hence; the only option is to use the tilde symbol.
Thus; this is still an issue.

In the scenario; 'prometheus' directory is present inside the home directory root user; $HOME gets expanded to its value ( /root ) in the following command:
./prometheus --config.file=$HOME/prometheus-2.3.0.linux-amd64/prometheus.yml

[brian-brazil]

I switched non-login/login-shell to root to execute prometheus binary.

It sounds like you've been using sudo or similar and your environment has gotten a bit messed up. I'd suggest logging in normally as your usual non-root user and starting from scratch from there.

[krasi-georgiev]

I just tried and ~ doesn't expand for me either.

ls ~/src/github.com/prometheus/prometheus/debug/simple.yml
-rw-r--r--. 1 krasi 437 Jun  7 14:09 /home/krasi/src/github.com/prometheus/prometheus/debug/simple.yml

go run main.go  uname_default.go fdlimits_default.go  --config.file=~/src/github.com/prometheus/prometheus/debug/simple.yml
....
...
open ~/src/github.com/prometheus/prometheus/debug/simple.yml: no such file or directory

[krasi-georgiev]

@amej do you think you can try to find the cause and open a PR?

[krasi-georgiev]

on a second thought @amej do you have any immediate use for that? unless it is trivial change and someone really needs this maybe not worth adding any extra code for this.

I usually use relative paths like ./prometheus --config.file=../../debug/simple.yml

[krasi-georgiev]

don't think we have an immediate need for this so will revisit if needed.

feel free to reopen if you have a good use case that requires this.

[lock]

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