Add missing example requirements

[pirgeo]

Description

Adds missing requirements.txt for one example (https://github.com/open-telemetry/opentelemetry-python/tree/main/docs/examples/metrics/instruments).

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

pip install -r requirements.txt
python example.py                      # this is already part of the docs

Does This PR Require a Contrib Repo Change?

• [ ] Yes. - Link to PR:
• [x] No.

Checklist:

• [x] Followed the style guidelines of this project
• [ ] ~Changelogs have been updated~
• [ ] ~Unit tests have been added~
• [ ] ~Documentation has been updated~

[pirgeo]

I tried to align with the other examples, which all have requirements.txt files. I don't have a preference for either, so I am happy to change it to simply adding it to the readme.

[xrmx]

I tried to align with the other examples, which all have requirements.txt files. I don't have a preference for either, so I am happy to change it to simply adding it to the readme.

Given the status of these requirements I think I have a stronger opinion now :sweat_smile: But let's see what maintainers think.

[lzchen]

I tried to align with the other examples, which all have requirements.txt files. I don't have a preference for either, so I am happy to change it to simply adding it to the readme.

Given the status of these requirements I think I have a stronger opinion now 😅 But let's see what maintainers think.

+1 for this, less maintenence the better :)

[ocelotl]

I suggest we keep the requirements.txt file, just remove the pinned versions.

[pirgeo]

I updated it to use >= instead of ==. Please let me know if you think this works, otherwise I'll just drop the versions completely!

[lzchen]

@ocelotl

I suggest we keep the requirements.txt file, just remove the pinned versions.

We don't requirements.txt file for the examples. Do we really want to start adding them for each example? This seems like more maintenance overhead.

[pirgeo]

I was looking at the other examples in that folder (https://github.com/open-telemetry/opentelemetry-python/tree/main/docs/examples/metrics/views, https://github.com/open-telemetry/opentelemetry-python/tree/main/docs/examples/metrics/reader, https://github.com/open-telemetry/opentelemetry-python/tree/main/docs/examples/metrics/prometheus-grafana) which all have a requirements.txt. Only this example (at least in the https://github.com/open-telemetry/opentelemetry-python/tree/main/docs/examples/metrics folder) doesn't have one. I am fine with not adding it, but having the requirements.txt definitely makes it easier to set up and try out the examples, since you don't have to guess which packages to install first. This might be especially helpful if you haven't worked with OTel before and these examples are your first touchpoint with the project.

[lzchen]

@pirgeo

Oh apologies, was referring to the other folders. If every other example in metrics has requirements.txt i don't mind adding this.

[pirgeo]

Changed it to use ~= as per @lzchen's suggestion.

[lzchen]

@pirgeo

Needs another rebase. Might want to change the permissions of the pr to allow maintainer edits so we can rebase for you next time :)

[pirgeo]

Ah, the organization fork does not have that automatically. I enabled the maintainer modification access now and rebased it